BMmonteSS

Well I've got the thing running pretty decent now. BLM's are all between 125 and 128. It idles good once it warms up, need to mess with the choke settings. Part throttle is amazing. It's the reason why I switched to TBI. I can burn them clear through first and Lay 5 feet of rubber into second at 3/4 throttle.

Here's the problem....after 3/4 throttle it all goes down hill. It runs fine under 4 grand but it starts breaking up after that, and really lays over after 5 grand. I started out with a carb and had the cpu doing the timing stuff. I got the timing curve all mapped out and the car really liked it, gained a half of mpg and a lot of part throttle response. Threw the 454 tbi on there and it took me a while to get it running decent but i finally got it, the top end miss started with the tb.

I've strapped a FPG to the windshield and it stays rock solid at 15 psi clear to 6000 rpm. I can move the wot throttle afr around and see the O2 moving with it. I've tried it with the O2 reading every where from .600 volts to 1.001 volts and higher, even though the carb had it runnin at around .850-.930. I'm 99% sure it's not a fuel issue.

Here's a list of replaced or checked items
FP------15psi all the time
new coil
checked module at parts store-----machine says it's good
wires----1500 ohm's on 2 foot wire....double checked with new wire and it's dead on.
new plugs
new O2
disabled knock retard
retarded and advanced timing

Does any one have a clue as to what could be the problem? I'm open for sugestions, comments........ or directions to a cliff to push this thing off of.

Dewey316

what are you o2 mv's at? when going WOT, also, what is your timing above 4k.

do you get any knock at all, wether knock retard is disabled or not, you should check your knock counts. it probably isn't a fueling ussue, i would agree, i am betting you either have way to much timing, or way to little.

also, refresh my memory on what your combo is. if you could post a screenshot of your timing and or a graph of your timing, that would really help.

BMmonteSS

I'll try to post my timing curves and VE curves tonight if I can get a chance, heck if you wanna look at my bin I'll e-mail it or put it up here for you to look at.

Right now i'm runnin between .890 and 9.60 mv at wot. It starts at 1.001 volt at 3000 and slowly leans out to .890 by 5500. I've tried it all over the place, leaner and richer and even much richer. Like I said where I have it now is in the ball park to where it was with the carb. It even acts lean and rich when the O2 says it's rich and acts lean when the O2 says it's lean. It still just misses and pops the same with both settings.

Timing is set at 33 degrees totall. I was chasing some false knock around for a while thats why disabled the retard and have the safe timing setting. I had ran as much as 38 deg total with the carb but it relly didn't do anything for the butt dyno after 35 deg. The exhaust leak that was causing the false knock finaly got big enough to quit tripping the knock sensor so now I have no knock at all. I sometimes get a burst or two from the missing but It doesn't always come up

Dewey316

you can e-mail me your bin if you like

dewey_316@hotmail.com

i won't be able to look at it until i get home from work tonight though.

also, when you are dataloging WOT, what are you MAP readings above 4k?

BMmonteSS

I won't be able to send it till tonight so that works out. i'm not exactly sure what the map is but I get the O2 voltages in the 95 block and sometimes a little lower if it's missing real bad. By the way thanks a alot, I'm really getting fed up with this, any help or suggestions will make my life alot easier. :hail: I'll try to get a good data log and save my blm and O2 tables on my way home from school, should be able to get some good data 50 mile trip with lots of hills and divided highway

Dewey316

i'm really interested to see if you are pulling vaccume at WOT above 4k myself.

RBob

iTrader: (1)

How much HP are you expecting the engine to make and which injectors are you using?

Once the engine starts to break up ignore the O2 sensor, it is lying to you.

RBob.

BMmonteSS

So far my 1/4 and 1/8 mile time with the carb have been
Hagerstown
1/4 14.1
mph 96

1/8 9.1
mph 75

Charleston WV (with new exhaust)
1/8 8.97
mph 77

My guess with my 3650 pound car with me in it is around 300-330 with a good bit of torque considering the mass of the vehicle. I really don't think the the TB is too small. The injectors i'm using are out of the 454 tbi but the colors were rusted over so i'm not sure which ones they are. I know the O2 isn't acurate but could the miss be hiding the leaness? I mean it starts peg rich down low and just gradually comes down to .900 or so volts. If for some reason I wasn't getting enough fuel wouldn't the O2 be lean up till the point where it starts missing and then go rich? The only thing in the code that bothers me is that I have the bpw constant set at 126, shouldn't it be set much lower like 94-100? Thats what my calculations say it should be but I can't get my VE table set right without it being set up here. Well I'll be heading home from school soon so i'll post my data log of the problem and my logged blm and O2 tables. Once again your guys rock

va454ss

iTrader: (1)

Don't trust the narrow band at WOT!

My truck is experiencing the same thing, but the plugs indicate lean.

I believe you need more fuel.

BMmonteSS

Ok got some data for you guys to look at.
But I don't know how to do a screen shot of what i'm lookin at so I'm gonna send out packets of my bin along with my data logs. Who's interested?????

Dewey316 you have mail!!!!

Dewey316

CTR + Printscreen, or ALT + Printscreen (cant' remeber which is which)

then open paint/photoshop/whatever program you like

and paste.


i'll check my mail here and look at the logs, i can look at the bin later tonight

BMmonteSS

Here's my 3rd gear log. It's a roll from about 60 to 105 the mph figures are 10 mph fast.

Dewey316

had you started to break up on that log? at what RPM did it start to have the problems?

although every 'looks' failry normal.

BTW, what cam are you running?

BMmonteSS

Yeah it broke up as usuall a little at first right at 4 and got real heavy right before I let off. Sorry the log is so short I had my friend runnin the lap top while I drove.The only thing I can see is the map reading wavers just a bit.

I'm running a comp cam's extreme 4x4 cam
216 .462
228 .480
111 lobe sep

It idles around 45 to 50 kpa and is really quite docile. It really needs the 2000 stall that I have though, it didn't like the stock one, it would just bog and then spin about 20 feet out.

My bin is a frakenstein of bins. I'm using anything that has to do with injectors out of a 454 bin and I'm using the filter and lag constants out of a 4.3bin. I'm not completely sure what bin this started out as since I was kinda thrashing when I got it runnin, I'm pretty sure it's a 305 truck bin, but almost everything has been changed to either the 454, 4.3 or my own settings. Let me know what you find, I'm gonna try to work on a completely new bin tomarrow after i get through my Thermodynamics test, how ironic I'm can't get my dang engine to run right and I'm learning all about it in thermo.

RBob

iTrader: (1)

Previous response was lost, don't you just hate that? Slightly different this time. . .

Anyway, I am going to say that you are lean. The injectors are either 75 #hr or 80.5 #hr at 13 psi. So even at 15 psi it isn't enough fuel. The biggest drawback is that you don't have injector PW's in the data log. This data is good to have so that it is easy to tell that the injectors are full out.

As it is I think is would be best to bump the fuel pressure to 20 psi. Then set the BPC accordingly (90-100, or so). If the injectors are 80.5#hr then they are good for 274 HP at 85% DC (at 13 psi). Those injectors at 20 psi are good for 340 HP at 85% DC (.5 BSFC). This is a safe area to start out with. Can always lower the FP once the tune is roughed in. You should be able to get the injector PW out the ALDL. Something to look into.

After these changes get the idle and low speed stuff roughed in. Then it will be easier to drive the car.

RBob.

vwdave

Questions on reading the spreadsheet.

INT - Whats that and how does it affect tune?
Rich Lean - Where is that number supposed to be?
Volts - Alternator voltage or something?
BLM - Whats that and how does it affect tune?

BMmonteSS

the more I think about it the more I think it really is just lean. It is the only logical explanation as to why my bpw constant is as high as it is. I really don't understand why the crappy O2 is lying to me but it has to be.

I have made my fpr adjustable but i'm pretty close to maxing it out, is it possible to get 20 psi with the stock spring?

Also the blm's on that pass don't lock at 128. Is that normal or is that somthing that aldl doesn't pick up on?

Ohh yeah almost forgot I really wanna get my pw in the aldl stream do you know the locations in the bin that need changed in order to get it to do that. I couldn't really follow you in your timing only paper....which by the way is awsome and really helped me understand how the whole timing thing works. Also I assume I can use ppII's software to edit the hex to do this correct?

VWdave

BlM is the long term fuel correction. Also kinda known as the coarse fuel correction.

INT is the short term fuel correction also known as the fine adjustment.

Volts are the battery volts.

I'm not completly sure what the rich lean counter does but I think it's kinda like a lookup the ecm uses for calculation somthing. It's not that important.

vwdave

Thanks.

*Feels a little more L33T with tuning now*

Dewey316

Yeah, i'm guessing lean also.

i went ahead and attached the graphs of your fuel maps. notice that right a 4k, you fuel actualy goes DOWN (using the 3200 cell on VE table 1 + the VE 2 for that RPM)

i would suggest either going RBobs route, or maybe initialy (easy test) is to give it some more fuel in the VE2 table over 4k.

Dewey316

VE2

vwdave

VE = Volumetric Efficiency?

*I'm trying to learn more, so please excuse the stupid questions*

RBob

iTrader: (1)

vwdave: yes: VE = Volumetric Efficiency?

BMmonteSS: which ECM are you using?

The BLM doesn't lock at 128 in PE mode. The code checks to see if it is less then 128 and if it is does not use it. If it is greater or equal to 128 it is then used in the PW calc (adds fuel).

RBob.

BMmonteSS

Yeah my VE curves aren't pretty. The lower half where I have gotten some good logs is pretty close but above that it's kinda messy. I have tried a rich bin not too long ago I basically maxed the VE curve out at 100 % above 36 and dropped the PE afr to 11-1 and it did the same thing. The O2 pegged on that one pretty much locked at 1 volt. If in deed it is still lean the only way I can fatham that it is, is if my injectors are going erratic and going so lean that the O2 is taking a fit.

Rbob: I'm running a 747 ecm with a big cap dissy. Also does the 747's PE afr table only go to 3600? The more I mess with this the more I wish I would have found a 746 or just went with a 730 and tried to get it to run the TBI stuff

Well here's the plan I'm gonna find a way to get the FP up to 20 psi. I would like to run as much pressure as possible and still be able to idle any way. Then I'll try to get this thing as rich as possible and see if my miss goes away and turns into a nice thick bog. That way I can sneak up on what it really needs without popping a hole in the piston.

I can't stop looking at that blasted NB O2.... I know what the motor liked with the carb on there and the O2 wasn't pegged out. I Just need to unplug the little bugger and magically come up with the cash for a WB.

By the way how does everything else look in my bin? Am I generally going in the right direction?

translation for vwdave
NB = Narrow Band O2 sensor aka what the general uses
WB = Wide Band O2 tells you exactly what your motor is doing no guessing
PE AFR = your air fuel ratio in power enrichment mode
hole in the piston = not good

Dewey316

lol, i didn't get a chance to really dive into it last night (and i was a little drunk when i did look at it ) but i'll check it out more, i'm still going to give your spark tables the once over.

BMmonteSS

lol, hey maybe thats my problem I've been sober while tuning on this thing. I always wrote my best english papers trashed so maybe I should start tuning trashed No wait that won't work.

Any way....That would be great. My timing curves have a good bit of time in them, I had about two months worth of tuning on them before I swaped in the tb. I have the warm bias set to 0 and the cold bias is setup to yeild 0 when it's warmed up so whats on the main spark curve is what is at the crank plus like 1 deg of PE spark. I picked up a half of mpg with that spark curve over what my mechanical disy gave me. Well that curve with about 3 degress added in globally. I set it up safe when I went false knock hunting.

Dewey316

would be very nice to get logs with the PW in them, as it is now, you pegged the o2 in a couple of the logs i looked at, what has me wondering is that you fuel actualy goes downhill from 4k which is where you start breaking up.

if you go above 4k without having your foot all the way to the floor, does it still break up at the same point, or does it get a little further up in the RPMs before breaking up?

vwdave

Thx, but I know all of that, thats why I didn't bother asking.

Is it alright if I AIM or MSN you so I can try to learn more?

Dewey316

feel free to give me a try, in the evenings i am on as

AOL: JUAN Dewey 3 16
MSN: dewey_316@hotmail.com

if the only chance you have is during the day, i can get ya on AOL from work (can't give that screenname out) but if you give me yours, when i have some time i'll msg you.

Ronny

iTrader: (1)

would not a trip to dyno with A/F ratios show you a lot? I run a 9 LBs FP on a 350 cid with 90# fuel injectors and was around 12.2 /1 at 5500 prms. why the need to go to 20 lbs FP? with a BPW of over 100(in his case) if i read that right, would not the injectors think they are small and put out even more fuel? my BPW is set at 94 for me. my HP i assume is 280?

BMmonteSS

dyno with a wb O2 is about an 5 hour drive from me.... well I really don't know how far away it is but it's not in my state. I was thinking the same thing about the bpw, it shouldn't be at 126 and still be lean on the top with bbc injectors at 15 pounds. I'm starting to think these injectors are either 350 injectors or are just not flowing what they are supposed to. The spray pattern looks good but who knows. I just ordered a fpr spring from top down so thats my next step. I may put the ls1 brake setup on hold and get a WB for christmas. I would really like to get this figured out before then.

Any one care to comment on how to get your pw in the aldl stream, also having the timing in there would be helpful as well.

vwdave: my IM is BMmonteSS and my email is BMmonteSS@aol.com feel free to e-mail or IM me anytime you would like. I hope you didn't take my last comment the wrong way I was just poking a little fun. I'm no expert but I would consider my skills luke warm so I'm sure I could help you get on your way.

RBob

iTrader: (1)

For all the '747 junkies out there a bunch of tables have the RPM scaling as follows:

400
600
800
1200
1600
2000
2400
3200
4000

Nine RPM values for a 9 line table. The tables include:

TPS vs RPM THRESH FOR WOT TBL @ $D47D
WOT FUEL @ $D486
RETARD ATTACK RATE vs RPM @ $D18D
MAX KNK RETARD LIMITS IN PWR ENR vs RPM @ $D17F
RETARD RECOVERY RATE vs RPM @ $D196

Then to get the sync PW on the ALDL line make these changes at the addresses shown:

Addr: Value:
$D4E7 $00
$D4E8 $AB
$D4E9 $00
$D4EA $AC

This puts the PW into the PROMID field of the scan tool. Take whatever value is displayed and multiply it by .01526 and add in the injector bias value (from $D2DA) and the end result is the PW in milli-seconds. So if the PROMID is 232 and the injector bias is .397 msec, then 232 * .01526 + 0.397 = 3.94 milli-seconds.

Have fun,

RBob.

Dewey316

RBob :hail: you are the man.

i know your the master at this stuff... so i'm going to ask.

do you know anyway to display total spark advance on the 8746?

RBob

iTrader: (1)

Same as above, different locations and different math.

Addr: Value:
$D414 $00
$D415 $61
$D416 $00
$D417 $62

The math will be the displayed PROMID value * .352 + the initial timing as set in the bin.

So a PROMID of 91 and 6 deg of initial = 91 * .352 + 6 = 38.0 deg SA.

If you want the PW then use $AA and $AB instead of the $61 & $62. The math will be as it is for the '747 above.

RBob.

BMmonteSS

wow thanks Rbob, I'll get that changed and hopefully get some logs tomarrow and see what she tells me.

I'm going for the lap top as we speak to take a look at those tables and see if any of those just happen to have some setting go funky at 4 grand.

vwdave

YOU SUCK!!!

j/k

Nah, its cool, I have pretty thick skin. Thanks for your help so far guys.

BMmonteSS

Ok, update time.....Well I'm using a asdz based bin now and my part throttle is a little cleaner. Swapped over all pertinent stuff,VE,spark, injector const, ect. Still have the high end miss, tried maxing out the VE talble about 3200 and set the PE AFR to 11.5 to 1 and she still misses.

I got my PW to spit out the aldl and it showed an increase with the richer bin. I went from aroun a 6.5 msec to a 7.9 msec PW. After reading through the hack I think I found where it says that any PW bigger than 11.9 is held over for the next fireing. So that means I'm nowhere near maxing these babies out.

Wierd thing though is the O2's didn't all peg a 1 volt. They stayed pretty close to where they had been before. I actually looked at the data log this time and not at the O2 table that winaldl puts together for you. So maybe my damn injectors are just giving up the gohst. I watched behind me today too and she blows grey smoke when I'm WOT so it has to be rich. I'm confused and tired of messing with it. Think I might throw the carb back on and see if it does it with it too. I'm startin to lean towards collapsing lifters or some kind of mechanical problem.

RBob

iTrader: (1)

At 7.9 msec you are static at 3800 RPM or greater. . .

RBob.

Dewey316

that would sure explain alot. i think you found your answer BMmonteSS

Ronny

iTrader: (1)

static is the injector is at 100% and maxed out?

RBob

iTrader: (1)

Static is at 100% or greater. The '747/'8063/'8746 ECMs fire an injector every time a plug fires. There are two injectors. They alternate on plugs firings.

Before I go too much further this is in synchronous mode. Sync mode is sync'd to plug firings. This is the most common mode. I have seen a few cals that are always in async mode, but never an f-body cal.

So for each revolution (V8) there are four plug firings. It takes two revolutions to fire all eight cylinders/plugs. Alternating injectors, that means each injector fires twice on each engine revolution.

At 4,000 RPM (revolutions per minute), divide by 60 for revolutions per second: 4000 / 60 = 66.67 revolutions per second. Invert this value for the time of each revolution (or frequency thereof): 1 / 66.67 = 0.015 seconds. Or, 15 milli-seconds (msec) per revolution.

With each injector firing twice each revolution we need to divide the amount of time in half: 15 msec / 2 = 7.5 msec.

This 7.5 msec is the amount of time an injector has before it is fired again (at 4,000 RPM). The higher the engine speed, the less time there is for an injector to deliver the required amount of fuel.

This is why it is important to keep an eye on the injector PW. Once the PW value exceeeds that given amount of time, no more fuel can be added. The darn injector is on ALL of the time.

At this point the only thing that can be done is to increase the delivery of fuel. Bigger injectors and/or higher fuel pressure is required.

As another data point at 6,000 RPM a TBI injector is static once it hits 5.0 msec of on time. For best results TBI injectors shouldn't be open for more then 85% duty cycle. At 6K RPM this is 4.25 msec's.

RBob.

BMmonteSS

Holy mother of pearl maybe I shouldn't have pushed off that cliff.

Man that's reasuring. Now to make sure I calculated that correctly. The injector adder is in Usec not msec but it looked like in the hack that you just take the 396 and use it as .396. Am I correct on that?

Here's a quickie snap shot of that log with the previous converson done to the PW

dimented24x7

iTrader: (2)

RBob, what does the $61 and $62 hex refer to? Ram locations?

RBob

iTrader: (1)

Yes to the adder (injector bias) time. Just add it to the calculated PW as .396 milli-seconds. This value does vary according to the calibration and injector combination. I have seen it span from 275 usec to 500 usec.

RBob.

RBob

iTrader: (1)

Yes, RAM locations. The SA values are variables, as they are changing on a regular basis. These along with 254 other variables are stored in RAM, TPS, MAP, SA, MPH, coolant, iat, knock counts, AE PWs, INT, BLM cells, etc.

RBob.

BMmonteSS

This is really getting exciting to me. At least now I know whats wrong and know which way to go to fix it. I hate having a problem and not knowing exactly whats wrong.

I have a high pressure spring on order from top down and I hope it'll be here before the weekend so I can give it a whirl. I'm really starting to think that I have a set of 350 injectors now that I know what the pulse width is doing. That would also explain my bpw injector constant problem too (126). Heck if I set it back to the stock 135 I woud have plenty of room i my VE tables then. Jprevost is running some crazy mph with stock 350 injectors at 20 psi so i'm hopefull that I will be able to do the same.

Correct me if I'm wrong but If I crank the pressure up and back down the BPW till my BLM's are in the ball park that should lower my PW on the high end shouldn't it?

Also another question is the list of ram locations for all those sensors some where in the 747 hac or can I find it else where? And if it's not just floating around out there what are the locations and numbers needed to out put SA on the 747?

Rbob: The amount of information you have shared with me is mind boggling. I just can't say how much I appreciate this. In return for this I'm going to start a new thread and summerize everything that I have learned so that some one who is doing the same thing I'm doing will be able to look it up in a search with no problem and save you a ton of time rehashing stuff thats already been said. I could do it up in word and have some of you guys go over it and cretique it......see that is not how you spell cretique and thats exactly why I would want you to look it over. This could make a good sticky. Maybe a 454 tbi swap post that is devoted solely to the programming changes required to swap the bigger tbi on too, I don't see much info on that side of the swap.

RBob

iTrader: (1)

For the SA on the '747 use $66 & $67 as the PROMID values. The math will be the displayed PROMID value * .352 + the initial timing as set in the bin.

So a PROMID of 91 and 6 deg of initial = 91 * .352 + 6 = 38.0 deg SA.


While you are replacing the regulator spring get the numbers off of the injectors. With that we'll be able to tell you which ones they are. The number that matters will look similar to this:

GM5234255*RPD

The other 4 digit number is only a date code and not needed.

Yes, a lower BPC will lower the PW with no other changes. The correct BPC value is a balance between the VE table and the required PW.

RBob.

RBob

iTrader: (1)

This is great idea. If you consolidated much of the TBI info into one document is would be helpful to others. Take everything that can be found: injector flow rates, TB flow rates, fuel pressure of the stock pump, then some info on WinALDL, info as to ALDL/SA/PW info and prom changes.

Basically a do-all for TBI in one spot. I think that the lack of this is a reason why so many folks give up on TBI. Let me know if you need any help or have any questions.

RBob.

dimented24x7

iTrader: (2)

*sniff* do i smell a tech article?

BMmonteSS

I'll get to work on summerizing every thing that I have gathered here on this post as well as others. The only problem is deer season just came started in my part of the woods so that'll be delayed till the later half of this week. That'll give me time to get my new FPR installed and make sure that fixes the problem. If you guys have any good threads you think that should be linked or has some good info regarding tbi's and ecspecialy the 454 tbi let me know.

Ronny

iTrader: (1)

give up on TBI? i thought TBI tuning was easier than the others? Guess all i know is TBI! that other stuff looks like Greek???