In response to a brilliant suggestion, I'll start my own thread.

New to this board and would appreciate any help anyone might be able to provide.

Here's my deal: Swapped a 4.3L vin Z from a '93 Astro Van into an '82 Jeep Scrambler. Completely re-built the engine, bored 30 over otherwise stock. ECM is 16196395 BJLA and running all factory sensors. Transmission is a T-18 4-speed. Timing set at 0 degrees w/STC disconnected. Have not yet installed an exhaust system (no O2 sensor). Engine, harness, and TBI system are all from the same vehicle as far as I know. All wiring associated with the original automatic transmission was clipped and taped 6 or 8 inches from the ECM. Fuel pressure is on the low side of the range but steady at about 9.5 psi.

Symptoms: Engine starts great every time. After start-up, warm or cold, it will sit at about 1200-1500 rpm (no tach so I'm guessing) for about 5-10 seconds (longer if it is a cold start) then slowly settle to about 500-600 rpm. Idles very smooth. After revving the engine rpm will drop to about 1200-1500 rpm, pause there for 5-10 seconds, then slowly wander to about 500-600 rpms. If I disconnect the IAC while it is at the nice low idle, it will rev and return to idle like I think it should. I've tried 2 other junkyard IACs with the same results. No vacuum leaks that I've been able to detect.

I get a handful of codes that are all associated with the automatic transmission.

I will be crawling rocks when this thing is all back together so the high-idle pause is very undesirable.

Anybody have any words of wisdom?

Thank you.

 

Would I get a better response if I told you I am running a flywheel from a '92 Camaro... 'cause I am .

Based on some feedback from VetteC5RFrEak in his "Idling Issues" thread, I plan to hit the JY for a different TB to try. Any other suggestions would be apprecaited.

 

It is difficult to pinpoint the root cause for a slow idle return since you have the following two conditions:
1) Low fuel pressure - 9.5PSI (bring it to 13 to 15 PSI)
2) Unconnected O2 sensor.

I would try to resolve the first two and possibly reprogramming PCM to get rid of automatic trany codes (all it takes setting a right bit to disable automatic trany codes in $0D mask). Trany codes in '6395 might be (I am speculating here) kicking you into a limp mode which causes funny idle performance issues. Post in DIY PROM forum regarding your PCM (or do a search in that forum). IRC there is a current discussion in there to do just what you are looking for (manual or non electronic transmission with $0D mask )
$0D 4.3L m/t BJFD is listed for use a '6395 PCM.
https://www.thirdgen.org/forums/diy-...6197427-a.html


//RF

 

The slow return to idle is from the throttle follower routines.

RBob.

 

Thanks RF. I am hoping to get it in for exhaust this week or next and I'll work on the FP. The thread you linked has a lot of information that will take some time for me to digest. I wasn't anticipating a need to get "inside" the PCM at this stage to get it running OK. Consequently I haven't spent a lot of time yet trying to grasp all that is involved. I was planning to do some tunig at some point so I'll just accelerate that process.

RBob - Once I get into it I'm sure I will have some questions about what I may or may not need to do with the throttle follower routines.

Thanks again.

Dan

 

My car use to idle at 2k then would drop to 1k slowly and to 500 at the same time intervals. I cleaned the IAC and the whole TB and checked for vacuum leaks and came up with nothing and even check the shafts, I ended up replacing the IAC and now it will run up to 2k and then after a complete stop it will go back to 1k. Sometimes I turn the car off and turn it back on and it returns back to normal for a while then will start to do it again after a while. I know its the computer but the new IAC has made it alot better and the idle screw has not been messed with on my car.

 

Dan

To keep it simple at this stage I would proceed as follows:

1) Fix FP by bringing it to 13-15 PSI range.
2) Get a O2 hooked up and working. (Also, do you have VSS connected and working???)
3) Download BJFD EPROM image and burn it into a new 256k EEPROM. Swap out old BJLA EPROM from your MEMCAL module. This requires careful de-soldering of your current EPROM chip and installation of an adaptor PCBA. Contact Craig Moates for more information. There are couple of stickies in DIY EPROM.
http://www.moates.net/

//RF

 

Thanks for mapping out a process for me. It should go without saying that I need to keep it simple.

 

I finally got my exhaust and O2 sensor installed last week. Modified my fuel pressure regulator and got it up to about 11.5 psi. I will pull it off and crank it up a few more turns to hopefully get to 13-15 psi. Burner and adapter are on order from Moates.

RF - I do have a VSS installed and it appears to be working - no code stored.

 

Great - keep us posted as to your progress...

 

Got my emissions inspection, VIN inspection, passed emissions test (after failing due to leaky gas cap), and finally got registration and plates...first time in 10 years it is legal on public roads!!!

Using Moates Burn2 I loaded a new EEPROM w/ the BJFD image and installed it in the PCM using Moates MemCal adapter. With key in the "on" position I get no SES light and the fuel pump runs constantly and does not shut off unless I turn the key off. Any ideas what I might be doing wrong?

Dan

 

ECM is failing to read EPROM contents.

Do you know what is the EEPROM chip size (or a part number)???? This is important since EPROM programmer must be told were to put bin file (physical address). I'll check tonight.

//RF

 

Part number is 27SF512 which I believe is 512 Kbit. The addresses I used in Flash & Burn are 000000 start and 00FFFF end. Maybe I misinterpreted something?

Dan

 

OK - swap start and stop addresses - ECM loads from the highest address and works it way down: Start = 00FFFF, Stop =00000 which correspond to 64 kB.

Make sure that run verify after burning bin file.

//I've looked at BJFD in Tuner Pro - it looks like Mask ID is at $4008//

//RF

 

RF - I thought I replied to your last post but I guess it didn't make it from my PC to the board...no wonder I never got an e-mail reply notification!! DOH!

Anyway, the Flash & Burn software defaults to 00000 start and 00FFFF stop. When I reverse the two I get an error telling me the addresses may be reversed so I'm still lost.

Also, I'm not really sure what you are trying to tell me with "//I've looked at BJFD in Tuner Pro - it looks like Mask ID is at $4008//" I don't see that address in the "Item Summary List" although I'm not sure that's where I should look.

As always, thanks for your help.

 

Let me do a screen capture of that bin tonight and post it. Can you perform EEPROM verify after you upload bin to the EEPROM??

//RF

 

I do get "verification succeeded" confirmation.

Dan

 

Dan

If you made any changes to the bin file in TunerPro the bin file check sum must be re-calculated. TunerPro RT does that automatically, but I am not sure if other programs do the same. The mask id '0D' is stored at EEPROM at offset $4008 as shown below. You should be able to see this in your BIN file editor.

//RF

 

Not sure what I was looking at before but now I do see Mask ID = OD at $4008. What I don't see is a flag to set for manual/automatic transmission. My best guess is that I need to "un-set" all the Transmission Diagnostic Error flags?

Dan

 

Yes, looks like all transmission related flags are un-set in BJFD mask.

//RF

 

Yes, looks like all transmission related flags are un-set in BJFD mask.
In flags / Switches there is a flag that selects if you have manual transmission at offset $400F - set it to checked for manual operation.

//RF

 

Thanks, RF. I'll burn it and try to see how it does tomorrow. I think I may have been looking at a funky BIN previously. I downloaded one from a different source (DIY-EFI)tonight and it looks a lot different in TunerPro RT. Don't recall where I got the first one. There's about 2 feet of fresh snow on the ground and it is still coming down. I may have to dig my way to the garage!

Dan

 

I hate to bring it up body, but it is going to be in the 80's here in So-Cal tomorrow. Not much of marine layer. Yard work for me tomorrow.....

Drop me a PM if you want compare BINs

//RF

 

My screen looks a lot different than the shot you posted. Under Flags/Scalers I'm seeing only AFR Mode Words 1 through 5, IAC Option Words 1&2, and Engine and Transmission Diagnostic Errors - no flag for MT/AT. I'll pm my BIN and XDF and would really appreciate your comments.

And, yah, springtime in the Colorado Rockies - should be in the 70's again early next week.

Dan

 

Much thanks to RFmaster I got the BJFD loaded and burned. Not proud to admit that part of my problem was installing the chip backwards in the ECM socket

Anyways, turn the key, CEL lights up, fuel pump runs for a few seconds then shuts off. Turn it over and she starts right up and my idle issue seems to have been solved!!

However, and there's always a however, on a short drive down my road, it throws a 24 code (VSS) and stumbles, chokes, and pukes under any throttle whatsoever. I had no VSS code with the BJLA bin so maybe there's a clue there? So, unless someone has a magic bullet to shoot me, it's time for more readin' and digestin' and getting set up to log data.

Dan

 

lol wow sounded like a nightmare!!! i would have given up LONG ago and put a carb on it haha. well i bet after it finally started and ran right that nothing could get a smile off your face right? lol

 

Dan
VSS error code 24 can be temporarily disabled by going into TunerPro, under Flags/Switches find Error 24 Transmission Output Speed Low. Small window should pop up - un-set check mark. It does not solve the problem, PCM still needs VSS information for its calculations, but now SES will not be poping up.

Get a data log going - just idle and off idle to see what is going.

//RF

 

All of a sudden got busy with life but got data logging cable on order and should be back at it in a week or so.

Carbs and me don't get along...can't seem to even look at one without it getting all upset and pitching a fit. So I intend to make good friends w/ my TBI. Not to mention there's 3500 ft. difference between my house and my work plus another 4000 ft. to some wheeling spots that I frequent. Gotta love the ECM for that!

Dan

 

Ahhh being busy - that's good

Carbs are so 20th century... Yep, when I did my first conversion it was like going from a dungeon to summer cottage! Instant start-ups, non of these 1800 RPM warm ups for 5 minutes, silky smooth idle, instant throttle response (advance curve in original dizzy was FUBAR), highway MPG improved from 12 MPG to about 17.

//RF

 

Got my cables yesterday and scored a laptop for the unbelievable low price of $0.00 (surplus from work)! The battery is toast but an inverter should do the trick for 1/3 the price.

There are lots of datastream files at Moates.net that look like they'll work. I'll try this one first. Any tips or cautions?

Dan

 

any updates?

my car now seems to idle at 1500-2000 RPM on a cold start up and after it warms up. it goes back to a normal idle of 600-1000 RPM. Is this normal for a Crossfire Injection car or am I just paranoid?

 

My idle issues disappeared when I switched from the BJLA prom to BJFD and set the flag for a manual transmission.

Also, the engine was shutting down anytime I hit 48 mph. I figured out that my VSS was putting out twice as many pulses per rev as was expected by the PCM. It thought I was going 96 mph which was the max speed set in the chip. Reset that to about 190 mph and problem solved ( or masked).

Started logging data to tune my fuel tables. It seemed like I was doing more harm than good-my tables looked worse than when I started. Then my laptop croaked and I've been trying to get it fixed or replaced ever since. Hopefully will be back in business in a week or two.

 

I have a question on HOW to do the screen capture image as shown in replies #18 and #21.


I've been "following" this thread and other TF threads with interest as I have come to the conclusion the issue of hung idle is one the issues I need to resolve on my 58mm bodied TPI with 230/236 comp cam.


Thanks to all for the prior works.

 

On PC computer running XP (and below) Windows use combination of keys:

Shift + "Print Screen" -> open paint program (supplied with windows), paste. Cut out portion of what you want to capture - save in a new file as JPG or PNG.

ALT + "Print Screen" -> will take a screenshot of the currently selected window, not the entire screen like the normal screenshot function. This is very handy as it minimizes amount of cropping in paint.

Starting windows Vista, Microsoft has included a utility called the Snipping Tool to make capturing screen shots easier.

There are numerous screen capture utilities.

I hope this helps.

//RF