4L80E shift Harness and TP defintions $0E
05-28-2011, 06:35 PM
#1
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
4L80E shift Harness and TP defintions $0E
I've done a conversion of a 502 w/Edelbrock MPFI based on '95 ECM 7427. I had the harness made by Howell. They also included a trans harness, so I could convert to a 4L80E. The 4L80E is in, it will drive down the road, but will not shift. Just runs in first gear. It seam like it is reading the speed sensor. The mph works on the aldl, but some of the other data is erroneous. Seams like every $0E defintion I have found, has some stuff that doesn't make sense. It all works fine for the engine, but the trans stuff is all over the place. Like it tells me I'm in gear 65. Input shaft speed is over 6000 RPM at idle. I get errors on the shift command flags. Does anyone have access to a correct trans definition for TP 5? The one on the TP site don't work and everything else I have found is messed up. Makes it difficult to troubleshoot.
Secondly, all the wiring diagrams I have seen are pretty vague when it comes the trans wiring. There is a module on the outside of the trans that tells what gear the shift lever is in. I have no harness for this module and no wiring diagram of where that harness is supposed to tie in. I think the ECM is thinking the vehicle is in park, but I have no idea how to tell it otherwise.
Secondly, all the wiring diagrams I have seen are pretty vague when it comes the trans wiring. There is a module on the outside of the trans that tells what gear the shift lever is in. I have no harness for this module and no wiring diagram of where that harness is supposed to tie in. I think the ECM is thinking the vehicle is in park, but I have no idea how to tell it otherwise.
05-29-2011, 04:11 PM
#2
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
The PCM uses the internal 'manifold pressure switch' assembly to determine gear position, the external switch is park/neutral safety and backup lamps.
You're likely not in first gear - fail-safe gear position is second gear, you can check this by seeing if no power is applied to the shift solenoids.
Have you double checked Howell's harness against the correct factory wiring?
You're likely not in first gear - fail-safe gear position is second gear, you can check this by seeing if no power is applied to the shift solenoids.
Have you double checked Howell's harness against the correct factory wiring?
Last edited by 71403; 05-29-2011 at 04:17 PM.
05-29-2011, 09:15 PM
#3
Supreme Member
Join Date: Oct 2002
Location: Idaho
Posts: 1,096
Likes: 0
Received 0 Likes
on
0 Posts
Re: 4L80E shift Harness and TP defintions $0E
Here's a link to the definition files your looking for. I have the trans wiring diagrams I will upload there as well. HTH!
05-30-2011, 02:12 AM
#4
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Did the link not post?
I've not checked the wiring against a factory drawing. I didn't think about them misswiring. I did check the range pins. The "park" pin is high when in park. All other conditions, all pins are low. I don't know what conditions the other pins should show anything. Is there a chart? I do know it is in first gear. Since my first post, I took it out again, at ~35 mph, it shifted into second. One of the adx files does seem to show the solenoids correctly, when put in drive, one solenoid fires. I do know the Vss is working, I saw the pulses on a scope.
I've not checked the wiring against a factory drawing. I didn't think about them misswiring. I did check the range pins. The "park" pin is high when in park. All other conditions, all pins are low. I don't know what conditions the other pins should show anything. Is there a chart? I do know it is in first gear. Since my first post, I took it out again, at ~35 mph, it shifted into second. One of the adx files does seem to show the solenoids correctly, when put in drive, one solenoid fires. I do know the Vss is working, I saw the pulses on a scope.
05-30-2011, 02:28 AM
#5
Supreme Member
Join Date: Oct 2002
Location: Idaho
Posts: 1,096
Likes: 0
Received 0 Likes
on
0 Posts
Re: 4L80E shift Harness and TP defintions $0E
I may have forgot to paste it... here's a direct to definitions. You'll have to go to the wiring diagram albulm for the others.
http://eagle-mark.com/pictures/thumbnails.php?album=6
http://eagle-mark.com/pictures/thumbnails.php?album=6
05-30-2011, 03:00 AM
#6
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I had found that page earlier, but unfortunately there are no adx files for $0E. Well there is a file there, but it is only 5 lines long.
BTW:When going to TunerPro definition page, there are ADX files there, but they will not load. It keeps giving an error that there Names must start with an alphabetical character. No matter what I do, I can not get rid of the error.
BTW:When going to TunerPro definition page, there are ADX files there, but they will not load. It keeps giving an error that there Names must start with an alphabetical character. No matter what I do, I can not get rid of the error.
Trending Topics
05-30-2011, 12:51 PM
#8
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Cool and thanks. I have now verified that those switches are working correctly. The only weird thing is the speedo on the aldl is way low- maybe half what it should be. Not sure why, I programed the DRAC, so it should be OK. I was given 3 different DRACs, I've tried all of them, the other 2 I did not change the programing. Even so, with the speedo reading 20 mph and no load, it still does not up shift. SOL goes active and then just stays on. Does this just mean I'm SOL eh? - OK bad play on acronyms.
I really can't think of any other reason why this thing won't shift. I even started out with a fresh clean OEM BIN, changed the fuel, spark, injector sizes to match my current BIN and tried that - it still will not shift. If I can't think of anything else, I may have to punt and buy and external controller. I hate to spend the money on something redundant, but I have no idea what else it could be.
I really can't think of any other reason why this thing won't shift. I even started out with a fresh clean OEM BIN, changed the fuel, spark, injector sizes to match my current BIN and tried that - it still will not shift. If I can't think of anything else, I may have to punt and buy and external controller. I hate to spend the money on something redundant, but I have no idea what else it could be.
05-30-2011, 06:36 PM
#9
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
Can you try a standard scan tool to rule out a problem in the .ads file you're using? Got to get the PCM seeing the right vehicle speed otherwise you're tail chasing.
What vehicle is this in?
Stock shift points may not be what's needed for your combo. I've seen some cals that just don't like to shift without some level of TPS input.
What vehicle is this in?
Stock shift points may not be what's needed for your combo. I've seen some cals that just don't like to shift without some level of TPS input.
05-30-2011, 08:34 PM
#10
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
TPS is OK. The fuel injection system has been running for over 2 years. All the engine stuff has been working ok on the ALDL, its just a few of the trans items seem weird. This is in a 13,000 lbs vehicle. While I have test driven it a couple of times, I am also testing with the wheels of the ground running in my driveway. I'm beginning to wonder if Howell did something to the ECM to make it run without the trans initially. They stated the trans should be fully functional, they just eliminated the trans error codes. I have gone back and re-enabled them, based on the OEM prom, so I should still be getting error codes.
Does this ECM have a internal jumper for manual transmission? I'm wondering if they did more than just change the code.
Does this ECM have a internal jumper for manual transmission? I'm wondering if they did more than just change the code.
05-30-2011, 09:50 PM
#12
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
manual / auto is handled in the calibration, no internal PCM hardware changes.
Is the app the Revcon in your signature block? Asking because wondering what your actual speedo mechanism is since you say it's correct but the ALDL is off. IIRC factory Revcon has a mechanical speedo.
Didn't mean a bad TPS - I meant that running the vehicle on stands with no road load I've seen 80e calibrations that don't like to shift because the TPS stays at/near 0.
+1 on get a OEM GM calibration, not Howell mystery meat.
As a test, if your ALDL VSS is 50% of your speedo drop the shift tables by 50% and see what it does.
Is the app the Revcon in your signature block? Asking because wondering what your actual speedo mechanism is since you say it's correct but the ALDL is off. IIRC factory Revcon has a mechanical speedo.
Didn't mean a bad TPS - I meant that running the vehicle on stands with no road load I've seen 80e calibrations that don't like to shift because the TPS stays at/near 0.
+1 on get a OEM GM calibration, not Howell mystery meat.
As a test, if your ALDL VSS is 50% of your speedo drop the shift tables by 50% and see what it does.
Last edited by 71403; 05-30-2011 at 09:56 PM.
05-31-2011, 12:26 AM
#13
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
I really can't think of any other reason why this thing won't shift. I even started out with a fresh clean OEM BIN, changed the fuel, spark, injector sizes to match my current BIN and tried that - it still will not shift. If I can't think of anything else, I may have to punt and buy and external controller. I hate to spend the money on something redundant, but I have no idea what else it could be.
Sounds like something is screwy in the wiring.
Last edited by dimented24x7; 05-31-2011 at 12:34 AM.
05-31-2011, 12:31 AM
#14
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
Cool and thanks. I have now verified that those switches are working correctly. The only weird thing is the speedo on the aldl is way low- maybe half what it should be. Not sure why, I programed the DRAC, so it should be OK. I was given 3 different DRACs, I've tried all of them, the other 2 I did not change the programing. Even so, with the speedo reading 20 mph and no load, it still does not up shift. SOL goes active and then just stays on. Does this just mean I'm SOL eh? - OK bad play on acronyms.
05-31-2011, 07:21 AM
#15
Moderator
iTrader: (1)
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,432
Likes: 0
Received 225 Likes
on
211 Posts
Car: check
Engine: check
Transmission: check
Re: 4L80E shift Harness and TP defintions $0E
Check that the DRAC, first letter of the code is a 'C' or a 'Q'. An 'A' coded DRAC doesn't have the 40 PPR output.
RBob.
RBob.
05-31-2011, 08:55 AM
#16
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Just checked and there is no 40 ppr output, it just goes to high when the ignition is turned on. Per RBob, I will have to go back and check the first letter of the code. Where would this be, on the card? The plastic housing does not have anything on it.
05-31-2011, 10:52 AM
#17
Moderator
iTrader: (1)
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,432
Likes: 0
Received 225 Likes
on
211 Posts
Car: check
Engine: check
Transmission: check
Re: 4L80E shift Harness and TP defintions $0E
On a 'Q' and a 'C' series the PCB number is: 16132857A
RBob.
05-31-2011, 12:33 PM
#18
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Have not had a chance to get home an check, but a quick search and stumbled on this info:
http://www.tbichips.com/drac/
Does this mean I should have a VSSB, or would the DRAC still be OK, as long as it is the right part number?
http://www.tbichips.com/drac/
Does this mean I should have a VSSB, or would the DRAC still be OK, as long as it is the right part number?
05-31-2011, 02:01 PM
#19
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Just checked, 2 of thr DRACs I have end in 2570, one is 16161145A. None of that really means much, as each of these cards have NO traces going to pin 13. So my even though the harness is OK, the circuit board is open.
So it sounds like off to the bone yard to find a DRAC or VSSB. Is it critical which I get? Seems like a need a DRACstick solution.
So it sounds like off to the bone yard to find a DRAC or VSSB. Is it critical which I get? Seems like a need a DRACstick solution.
Last edited by Daveinet; 05-31-2011 at 02:08 PM.
05-31-2011, 02:14 PM
#20
Moderator
iTrader: (1)
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,432
Likes: 0
Received 225 Likes
on
211 Posts
Car: check
Engine: check
Transmission: check
Re: 4L80E shift Harness and TP defintions $0E
I don't know what if any difference there is between the C and Q series DRACs. In my testing of some of them I found that they have the same outputs. Note the one picture from the link you posted shows the code QDU, that is a Q series unit and will have the 40 PPR output.
RBob.
RBob.
06-01-2011, 02:53 PM
#21
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Third gear is a very pretty sight! Running in free air, so the shift was a little late, but probably all within the range of adjustment. VSSB from a '96. I've not calibrated it yet, just wanted to plug it in over lunch and see if we it shifted or if it was time to punt. $5 bucks from the U-pull it yard. I grabbed 2 just incase. Tonight I will calibrate up the VSSB and take it out for a spin. More later, on limited lunch break. Thanks for HUGE help.
One question. Does anyone know why the VSSB has 2 sets of jumpers - meaning which one goes to what function? The VSSB that I pulled from a '96 G20 van, the jumpers are not mirror image as suggested in the TBIchips pages.
One question. Does anyone know why the VSSB has 2 sets of jumpers - meaning which one goes to what function? The VSSB that I pulled from a '96 G20 van, the jumpers are not mirror image as suggested in the TBIchips pages.
Last edited by Daveinet; 06-01-2011 at 05:28 PM.
06-01-2011, 08:25 PM
#22
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
After my first drive, I've concluded my shift tables were programed by Obama. They are in super econo mode. Actually the speedo reading is off by 50% against the GPS. Not sure why that is. I calculated the tire circumference and gearing. It came out within a very reasonable range, actually it was within one number of the VSSB table, compared to a G20 van. RPM at 60 is ~2200. It doesn't make sense why it is so far off.
You know, one other thing that does not make sense to me, is why the shift tables are related to speed, rather than engine RPM. At full throttle I would like to shift at 5200 RPM, I don't care what speed that is.
I have to add something else. Something is very backwards. Since my speedo is reading half what it should be, my shifting should be way late, but instead, it is way early. On the other hand, since the shifting is way early, I would have assumed the Torque converter should have engaged early as well, but it would not engage at all, or at least up to 60 mph. So there is some conflict somewhere. This is a 2000 year trans running on a '95 computer. Could that be an issue?
You know, one other thing that does not make sense to me, is why the shift tables are related to speed, rather than engine RPM. At full throttle I would like to shift at 5200 RPM, I don't care what speed that is.
I have to add something else. Something is very backwards. Since my speedo is reading half what it should be, my shifting should be way late, but instead, it is way early. On the other hand, since the shifting is way early, I would have assumed the Torque converter should have engaged early as well, but it would not engage at all, or at least up to 60 mph. So there is some conflict somewhere. This is a 2000 year trans running on a '95 computer. Could that be an issue?
Last edited by Daveinet; 06-01-2011 at 10:16 PM.
06-02-2011, 12:41 AM
#23
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
You know, one other thing that does not make sense to me, is why the shift tables are related to speed, rather than engine RPM. At full throttle I would like to shift at 5200 RPM, I don't care what speed that is.
WOT shiftpoints will be determined by the kickdown values, I'm not familiar with them in $0E.
some conflict somewhere. This is a 2000 year trans running on a '95 computer. Could that be an issue?
Last edited by 71403; 06-02-2011 at 12:51 AM.
06-02-2011, 03:20 AM
#24
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
Not sure why that is. I calculated the tire circumference and gearing. It came out within a very reasonable range, actually it was within one number of the VSSB table, compared to a G20 van. RPM at 60 is ~2200. It doesn't make sense why it is so far off.
You know, one other thing that does not make sense to me, is why the shift tables are related to speed, rather than engine RPM. At full throttle I would like to shift at 5200 RPM, I don't care what speed that is.
You know, one other thing that does not make sense to me, is why the shift tables are related to speed, rather than engine RPM. At full throttle I would like to shift at 5200 RPM, I don't care what speed that is.
As far as the shift tables. The part throttle ones are in MPH. The WOT (kickdown mode) upshift ones are in terms of RPMs. The WOT downshift ones are in MPH because the PCM doesnt calculate the RPMs that the engine will be turning after the downshift. So, theyre in MPH. Heres the tables from the $0D. The $0E ones are similar or the same.
Code:
; ;~~~~~~~~~~~~~~~~~~~~~ ;-Kickdown TPS params ;~~~~~~~~~~~~~~~~~~~~~ ; L5D1B FCB 242 ;95% TPS, threshold to enable kickdown L5D1C FCB 230 ;90.2% TPS, threshold to disable kickdown ; ; ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ;-Kickdown cold MPH upshift modifier vs. gear # ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ; ; MPH mod. = (val-128)/2 ;Gear shift ; L5D3F FCB 124 ;1 -> 2 L5D40 FCB 122 ;2 -> 3 L5D41 FCB 128 ;3 -> 4 ; ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ;-Kickdown cold MPH downshift modifier vs. gear # ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ; ; MPH mod. = (val-128)/2 ;Gear shift ; L5D42 FCB 124 ;2 -> 1 L5D43 FCB 122 ;3 -> 2 L5D44 FCB 128 ;4 -> 3 ; ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ;-Kickdown mode standard/cruise cont'l transmission upshift RPM vs. gear shift ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ; ; RPM = val/8 ;Gear shift ; L5D45 FDB 32000 ;1 -> 2 L5D47 FDB 32000 ;2 -> 3 L5D49 FDB 65535 ;3 -> 4 ; ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ;-Kickdown mode hot transmission upshift RPM vs. gear shift ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ; ; RPM = val/8 ;Gear shift ; L5D4B FDB 30400 ;1 -> 2 L5D4D FDB 30400 ;2 -> 3 L5D4F FDB 65535 ;3 -> 4 ; ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ;-Kickdown cold upshift RPM modifier vs. gear shift ;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ; ; signed RPM = val / 8 ;Gear shift ; L5D51 FDB 63936 ;1 -> 2 L5D53 FDB 63936 ;2 -> 3 L5D55 FDB 63936 ;3 -> 4
06-02-2011, 07:36 AM
#25
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
It does seem counter-intuitive but that's the way they did it. Attached is a spreadsheet that can help visualize the shift points, I used it for WOT tuning but you can change the RPM values eg the 2200rpm entry to visualize other points.
Your sig mentions a "1.11 transfer case" - are you taking that into account or is that a 4wd low range?
WOT shiftpoints will be determined by the kickdown values, I'm not familiar with them in $0E.
I really don't understand the conflict between shifting early, but yet will not go into TCC lock up. You would think it should also go into lockup early, but it won't lock up at all. Also weird that the ALDL speed reads low, but it shifts early. Maybe unless I have the wrong signal to the 4WD input on the ECM.
06-02-2011, 02:38 PM
#26
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Under constants, is there some global changes I can make to fix everything? Specifically looking at RPM/VSS ratio, MPH filter coefficient, overdrive ratio, (which happens to match RPM/VSS ratio. What are these?
PS, I'm in shear panic mode as I am supposed to leave town Saturday morning, and only have a few hours tonight to work on it and maybe just a little time Friday.
PS, I'm in shear panic mode as I am supposed to leave town Saturday morning, and only have a few hours tonight to work on it and maybe just a little time Friday.
Last edited by Daveinet; 06-02-2011 at 07:12 PM.
06-02-2011, 09:19 PM
#27
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
The vehcile is front wheel drive. This is achieved by using a large transfercase/chaincase to run the driveshaft forward. There is a 1.11 step up in the chaincase. and it is accounted for. Speaking of which, the ECM has an input for 4WD. I assume this should be grounded all the time, is that corrrect? Ungrounded, shift points are way late - meaning shifting out of first at 30 mph (GPS)
Manual says the "normal" voltage found on 4WD pin both KOEO and KOER is B+. If "normal" is not 4low I would assume the pin should be ungrounded in your app.
PS, I'm in shear panic mode as I am supposed to leave town Saturday morning, and only have a few hours tonight to work on it and maybe just a little time Friday.
06-02-2011, 09:22 PM
#28
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I doubled the VSS/RPM ratio and also matched the Overdrive ratio. Shift points are dead on. Downshifts nicely, up shifts like it should compared to throttle position. Although it shifts a little hard anytime it shift. WOT the engine really dies when it shifts. It shifts at 4200 rpm, but the engine will easily turn 5200. I assume the computer is dropping back the engine during the shift. I can live with that.
HOWEVER, I still do not have TCC. I'm well within the range of where the TCC should be on, but it will not lock up. I'm scared to take it on a 1000 mile trip without lock up, as I would fear burning up the trans. It turns ~2200 RPM at 60, but I'm afraid of too much slip. Any thoughts or ideas what is going on with the Torque converter would be greatly appreciated.
HOWEVER, I still do not have TCC. I'm well within the range of where the TCC should be on, but it will not lock up. I'm scared to take it on a 1000 mile trip without lock up, as I would fear burning up the trans. It turns ~2200 RPM at 60, but I'm afraid of too much slip. Any thoughts or ideas what is going on with the Torque converter would be greatly appreciated.
06-02-2011, 09:31 PM
#29
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
Want to post your gear ratios & tire size for a VSSB ratio sanity check?
Tire size is 245/75/16 or 684 revs per mile according to TireRack, for a Transforce H/T. Diff ratio is 3.53 * 1.11 transfercase or 3.92 total. (1010000) I did also try the other DRAC, which was already set to the correct ratio, it made no difference.
Last edited by Daveinet; 06-02-2011 at 09:39 PM.
06-02-2011, 10:22 PM
#30
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
Something in that ratio math doesn't seem right. Think you're saying case is 11% underdrive, IOW the case ratio is .38?
30.5" tire dia * Pi = 95.8" circumference
(63360 * 3.92 * 40) / (95.8 * 128000) = .810878
Closest setting would be 0.808594 (1010011)
30.5" tire dia * Pi = 95.8" circumference
(63360 * 3.92 * 40) / (95.8 * 128000) = .810878
Closest setting would be 0.808594 (1010011)
Last edited by 71403; 06-02-2011 at 10:25 PM.
06-02-2011, 11:04 PM
#31
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I had .8379. The difference between my math and your math is that I used the tires rolling size, rather than the unloaded size. The Revs per mile is a measure of the wheel under load, which technically is more accurate.
Of course the fact of the matter is, either one is pretty close, and would not be off by a factor of 2, which is what my ALDL was telling me. Also the fact that I have doubled the number and it shifts right, confirms that somehow the info it is getting is off by a factor of 2. This trans was built by a rebuilder friend of a friend. I just have to wonder is the reluctor ring is wrong. This trans was originally out of a diesel. Since diesels turn so much slower, could it have been spec with a higher pulse count?
Should my input RPM match the engine RPM, or is that post torque converter? If the input RPM is high, does that prevent the TC from locking?
Of course the fact of the matter is, either one is pretty close, and would not be off by a factor of 2, which is what my ALDL was telling me. Also the fact that I have doubled the number and it shifts right, confirms that somehow the info it is getting is off by a factor of 2. This trans was built by a rebuilder friend of a friend. I just have to wonder is the reluctor ring is wrong. This trans was originally out of a diesel. Since diesels turn so much slower, could it have been spec with a higher pulse count?
Should my input RPM match the engine RPM, or is that post torque converter? If the input RPM is high, does that prevent the TC from locking?
06-03-2011, 12:13 AM
#32
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
Never had a problem using a 80E diesel trans on a gas app, always a direct swap minus converter.
Ratio error codes will usually inhibit TCC, some will force 2nd gear only too. Again I'm not familiar with $0E specifics.
Attached a DRAC/PCM diagram for reference. (C12 is clearly labeled wrong)
Ratio error codes will usually inhibit TCC, some will force 2nd gear only too. Again I'm not familiar with $0E specifics.
Attached a DRAC/PCM diagram for reference. (C12 is clearly labeled wrong)
06-03-2011, 01:24 AM
#33
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
As far as the MPH calculations go, the formula used IN THE PCM to determine what the ratio of MPH to the transmission output shaft speed should be is:
This formula converts the RPMs reported at the output shaft to MPH. This constant is a double byte, and is located at 0x5D1E in the $0E calibration.
There is also a value used to convert for the xfer case reduction in the calibration. When the 4WD low input is active, the PCM applies the multiplier so it can correctly calculate the MPH with the xfer case reduction included. This is also a double byte constant, and is located at 0x5D1C. To convert the raw value to a ratio, you divide it by 16384.
These are the two main things that will effect the MPH used for the shiftpoint calculations. Check your XDF to make sure what you have for your $0E matches. If you enter these in correctly, and hook up your 4WD input properly, the shiftpoints should remain more or less constant based on RPMs at P/T.
These only effect the MPH used in the transmission algo, not the one used in the engine/ALDL datastream. That one is static, and relies on a 2000 PPM signal, unlike the MPH used in the trans routines. If that one is 1/2 of what it should be, then it means that the VSS input is recieving only 1000 PPM.
Code:
8 x num. gear ratio x 12 x 5280
Raw Value = --------------------------------------- x 65536
512 x 60 x tire rad in in. x 2 x pi There is also a value used to convert for the xfer case reduction in the calibration. When the 4WD low input is active, the PCM applies the multiplier so it can correctly calculate the MPH with the xfer case reduction included. This is also a double byte constant, and is located at 0x5D1C. To convert the raw value to a ratio, you divide it by 16384.
These are the two main things that will effect the MPH used for the shiftpoint calculations. Check your XDF to make sure what you have for your $0E matches. If you enter these in correctly, and hook up your 4WD input properly, the shiftpoints should remain more or less constant based on RPMs at P/T.
These only effect the MPH used in the transmission algo, not the one used in the engine/ALDL datastream. That one is static, and relies on a 2000 PPM signal, unlike the MPH used in the trans routines. If that one is 1/2 of what it should be, then it means that the VSS input is recieving only 1000 PPM.
06-03-2011, 01:36 AM
#34
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
Since your using a chain-drive with constant reduction at all times, the 4WD input should be left inactive, or whatever is called for in the factory manual when the 4WD is not engaged. Your constant for calculating the MPH at 0x5D1E should be 44219 in the binary, based on the info you gave. Try updating it, and see how it shifts then.
Also, is your turbine input shaft speed sensor hooked up? If thats not present, you wont have any lockup.
Also, is your turbine input shaft speed sensor hooked up? If thats not present, you wont have any lockup.
06-03-2011, 08:37 PM
#35
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I finally changed the input speed calibration. Went one way, and it went into limp mode. The other way, it did not fix the TCC, but it did make my shifts a lot smoother.
How does this ECM determine if it has a 4L80E or a 700R4? IS this done in the MemCal? Is it possible that my memcal is the wrong one and not compatible with the 80E trans? How would I know what memcal is in this thing?
How does this ECM determine if it has a 4L80E or a 700R4? IS this done in the MemCal? Is it possible that my memcal is the wrong one and not compatible with the 80E trans? How would I know what memcal is in this thing?
Last edited by Daveinet; 06-04-2011 at 08:51 AM.
06-03-2011, 09:52 PM
#36
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
I think its more determined by how its calibrated. The big difference with the 4L80-E is the TCC management. The smaller things are the shift sol. states, force motor calibration, etc.
06-04-2011, 04:18 PM
#37
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
OK, I can only come to the conclusion that the reluctor rings inside the trans are wrong. I don't know how or why, but that is the only conclusion I can come to. I get a "negative slips prevent TCC from engaging". I've tried to understand how to set the input speed calibration, but I don't understand the calculation. The info I have does not make sense. I've also not been able to figure out how to monitor the input shaft speed in $0E.
06-04-2011, 04:33 PM
#38
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
Have you scoped the sensors?
The rear reluctor ring is a service part.
The rear reluctor ring is a service part.
06-04-2011, 09:04 PM
#39
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
OK, I can only come to the conclusion that the reluctor rings inside the trans are wrong. I don't know how or why, but that is the only conclusion I can come to. I get a "negative slips prevent TCC from engaging". I've tried to understand how to set the input speed calibration, but I don't understand the calculation. The info I have does not make sense. I've also not been able to figure out how to monitor the input shaft speed in $0E.
06-04-2011, 10:12 PM
#40
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I have seen the TIS on a scope, it looks pretty good. I think the error is because I changed the VSS calibration to make it shift correctly. I would like to match the input calibration to the same amount as I fudged the VSS, which is why I was trying to understand the meaning of the input shaft calibration.
I'm surprised the rear reluctor ring a is a service part. It is inside the back of the trans (not in the tailshaft.)
I'm surprised the rear reluctor ring a is a service part. It is inside the back of the trans (not in the tailshaft.)
06-04-2011, 11:16 PM
#41
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
The reluctor ring is pressed onto the output shaft in the place of, I think, where the worm drive was for the governor.
06-05-2011, 12:16 AM
#42
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,119
Received 428 Likes
on
368 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: 4L80E shift Harness and TP defintions $0E
I doubled the VSS/RPM ratio and also matched the Overdrive ratio. Shift points are dead on. Downshifts nicely, up shifts like it should compared to throttle position. Although it shifts a little hard anytime it shift. WOT the engine really dies when it shifts. It shifts at 4200 rpm, but the engine will easily turn 5200. I assume the computer is dropping back the engine during the shift. I can live with that.
HOWEVER, I still do not have TCC. I'm well within the range of where the TCC should be on, but it will not lock up. I'm scared to take it on a 1000 mile trip without lock up, as I would fear burning up the trans. It turns ~2200 RPM at 60, but I'm afraid of too much slip. Any thoughts or ideas what is going on with the Torque converter would be greatly appreciated.
HOWEVER, I still do not have TCC. I'm well within the range of where the TCC should be on, but it will not lock up. I'm scared to take it on a 1000 mile trip without lock up, as I would fear burning up the trans. It turns ~2200 RPM at 60, but I'm afraid of too much slip. Any thoughts or ideas what is going on with the Torque converter would be greatly appreciated.
As for the TCC locking, do you have the TCC Brake input into the PCM wired to +12VDC?? 4L80E TCC lockup solenoid is also on a different PCM terminal than the 4L60E.
06-05-2011, 01:06 AM
#43
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I read this at 12:30 am in the morning, laying in bed. What you said makes so much sense, I set the computer down, ran outside in my PJs, and looked at the DRAC wiring. Yep, it is backwards. It kept bugging me that my speedo was reading half what it should have been and yet my shifting was way premature. It fits your conclusion exactly. Even though I can't fix it and test it till tomorrow morning, I will sleep much better tonight. Thank you so much, you can not believe the load that has just come off my shoulders. I missed my Memorial Day trip and was supposed to leave Today for a 1 week vacation. I was fretting this pretty bad, as there were a lot of other people counting on me being on vacation.
06-05-2011, 06:41 PM
#44
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I've lost the battle completely! Swapped the wires and verified the correct wiring from schematics. The ALDL speedo output says that I'm doing 255 mph when I'm only doing 8 mph GPS. AS I speed up, the read out goes down and moves around and then climbs again. I have no clue what is going on. I tried a different DRAC, a different ECM. It all acts the same.
OK, here is what is weird. Running at idle vehicle raised in the air, vehicle speed is like 2 HZ, trans speed is ~100 hz. C10, which is unused is ~130 HZ. I don't see any output that is double the other output.
OK, here is what is weird. Running at idle vehicle raised in the air, vehicle speed is like 2 HZ, trans speed is ~100 hz. C10, which is unused is ~130 HZ. I don't see any output that is double the other output.
Last edited by Daveinet; 06-05-2011 at 07:26 PM.
06-05-2011, 09:21 PM
#45
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,119
Received 428 Likes
on
368 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: 4L80E shift Harness and TP defintions $0E
I've lost the battle completely! Swapped the wires and verified the correct wiring from schematics. The ALDL speedo output says that I'm doing 255 mph when I'm only doing 8 mph GPS. AS I speed up, the read out goes down and moves around and then climbs again. I have no clue what is going on. I tried a different DRAC, a different ECM. It all acts the same.
OK, here is what is weird. Running at idle vehicle raised in the air, vehicle speed is like 2 HZ, trans speed is ~100 hz. C10, which is unused is ~130 HZ. I don't see any output that is double the other output.
OK, here is what is weird. Running at idle vehicle raised in the air, vehicle speed is like 2 HZ, trans speed is ~100 hz. C10, which is unused is ~130 HZ. I don't see any output that is double the other output.
http://mattw.dyndns.org/4L80E/
As does this one
http://www.tbichips.com/drac/
06-05-2011, 10:08 PM
#46
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
I thought the wires were swapped, they were not. I started putting a scope on the ECM, rather than the DRAC and figured late at night I was seeing what I wanted to see.
I found DRAC C4 has double the output, frequency, so I connected the vehicle speed to that. That made the speedo work. It shifts a bit early, but not terribly so, but still no lockup. I did try running off C10, but then it would not shift at all.
I found DRAC C4 has double the output, frequency, so I connected the vehicle speed to that. That made the speedo work. It shifts a bit early, but not terribly so, but still no lockup. I did try running off C10, but then it would not shift at all.
06-05-2011, 10:48 PM
#47
Junior Member
Join Date: May 2007
Location: 7th circle of stop-n-go traffic hell
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Engine: X
Transmission: MT1
Re: 4L80E shift Harness and TP defintions $0E
Don't recall C4 being used in any factory app. But just checked and C4 is internally connected to C15 on the early style DRAC
C11 is the output to the PCM VSS input
C13 is the output to the PCM TOSS input
C15 is the output to the dash speedo
There's also a higher (128 ppr?) output to the RWAL on C10
06-07-2011, 06:35 PM
#48
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,119
Received 428 Likes
on
368 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: 4L80E shift Harness and TP defintions $0E
I thought the wires were swapped, they were not. I started putting a scope on the ECM, rather than the DRAC and figured late at night I was seeing what I wanted to see.
I found DRAC C4 has double the output, frequency, so I connected the vehicle speed to that. That made the speedo work. It shifts a bit early, but not terribly so, but still no lockup. I did try running off C10, but then it would not shift at all.
I found DRAC C4 has double the output, frequency, so I connected the vehicle speed to that. That made the speedo work. It shifts a bit early, but not terribly so, but still no lockup. I did try running off C10, but then it would not shift at all.
06-07-2011, 09:03 PM
#49
Supreme Member
iTrader: (2)
Join Date: Jan 2002
Location: Moorestown, NJ
Posts: 9,962
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Re: 4L80E shift Harness and TP defintions $0E
You should have your brake switch hooked to E13, and as said above, it should have +12V when the brake pedal is not depressed. If you just have +12 volts there, youll have to make some changes to the TCC logic to make sure its unlocked below 1000 RPM or so, or the TCC can drag the engine down while your braking. The pin for the PWM TCC signal is E11 on the 4L80-E apps. Pin E10 is the standard TCC on/off output.
06-07-2011, 10:45 PM
#50
Member
Thread Starter
Join Date: Sep 2008
Location: Jail
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: Revcon Motorhome ECM:16197427 BJKW
Engine: 502 HT W/MPFI, Thorleys, Magnaflows
Transmission: 4L80E
Axle/Gears: 3.53 + Transfercase 1.11
Re: 4L80E shift Harness and TP defintions $0E
The brake switch has relay on it, because of the LED tail lights. As it turns out, after a bunch more reading, I found the coil resistance is somewhere between 10 and 15 ohms. I found where someone had viewed the PWM and found that at cruise, it ran at 50% duty cycle. SO I hot wired it to ground through variable resister. (actually it was an old speaker volume control) Throwing a meter on it, I ran it down to about 6.5 volts. Added a push button switch and a latching relay through the brake switch, so it would drop out anytime the brake was hit. That worked very well, except once after driving in heavy freeway traffic, I forgot to push the button to lock it for a 10 miles. So 500 miles later, all is well. It got me to my destination. I've decided to punt, since there are too many unknowns and lack of over all success. I ordered a EZ-TCU trans controller. Since I'm in OH, I ordered it from Summit, it will be here in a day (before I go back to IL).