Prom ID shows 0???

[usetaboost]

Finally had somebody that knows what they're doin look at my car. Everything is fine except No prom ID on scan and it will idle in limp mode, Bad chip maybe??? Check with member fubar2578 for details, he looked at it.

 

[usetaboost]

ttt

 

[unix_punk]

So by limp mode you mean the check engine light is flashing constantly? If you haven't done it already, pull power from the ECM, reseat the chip and try again. If it still flashes right away with the key ON, then I would try another chip. You should also throw a bad eprom/socket code as well I think.

 

[usetaboost]

I don't think that's the problem. THis was happening with the stock chip also and that had never been removed. Car was all stock parts when I bought it.

 

[unix_punk]

Ok, but if the check engine light is flashing constantly, even with the motor off but the key on, then thats definately limp mode which is usually ecm/chip related. I dont know what else could cause limp mode, Ive only had happen to me when a chip wasnt seated correctly. Do you have another ECM to swap out and test? Is it throwing a code?

 

[usetaboost]

"limp mode" was commanded by the snap on scanner, I have NO CODES whatsoever. Car runs the same with stock chip and modded one-WON'T IDLE. Everything checked out good. Even tried setting minimum-no go Find it hard to believe BOTH chips are bad.

 

[unix_punk]

Ok, so the ECM didnt throw itself into limp mode then, correct? So the check engine light does not flash? Does the car just die right away or is the RPM all over the place? If it's the latter, I would check the MAF, I had one go recently and thats how it behaved.

If you want this thread to go anywhere, get fubar2578 to post any other details that you're missing here.

 

[usetaboost]

Nope, it doesn't throw itself into limp mode. The car just starts up and dies. He said everything looked dead on but kinda wondered about the MAF showing 6 gm/sec when the car wasn't running. tapped on it nothing happend, unplugged it, wiggled the connector, nothing. Plugged it back in and then showed "3". We both wiggled the connector with it plugged in and still nothing changed. Outside of that I've found nothing and neither has he from what I can remember. Give it some time, I'm sure he'll chime in.

 

[unix_punk]

the maf should read above 0 when the car is off. I dont think ive ever seen mine at 0...

Does the car run if you give it a little pedal?

Have you check readings on all sensors? Especially coolant temp sensors?

What scan tool are you using? Just that snapon you talked about above? If so, I suggest getting a directscan or powerlogger as those will show everything you need to diagnose this.

 

[usetaboost]

Yes just the snapon, double checked everything and anything. What is the powerlogger going to tell me that any other scanner is not? Yes it will stay runnin if u keep your foot on the gas. Coolant temp sensor OK.

 

[unix_punk]

well i dont know what you can see on the one you have, but the powerlogger will tell you everything that just about every sensor is reading. So you would be able to see if the coolant temp was incorrect for example. would also show you IAC counts as well, which could aid you in determining if the IAC is bad, or if the ecm is trying to correct the IAC too much/too little. Things like that. FULL THROTTLE SPEED - Store Front Page has them.

 

[usetaboost]

Shows everything any other will show. The IAC is new.

 

[unix_punk]

I guess your best bet would be to swap out the ecm, or swap yours into a known running car. Any chance on this?

 

[usetaboost]

LOL! Not around here. The rust belt is filled with mustangs and BB chevys. Anyone out there willing to lend out a loaner ecm and stock chip? Ahem...Jeremy? Got one around?

 

[Blazer406]

Does that snapon scantool show IAC counts? How often does it refresh (datapoints per second?). If it hooks to the ALDL connector which I assume it does, it won't see but maybe 1 frame every few seconds.... IMHO that is probably better than nothing.... but not much better. The powerlogger.... or DirectScan will show many frames per second..... easier to troubleshoot IMHO.

Does it stay running with minimum gas pedal applied?

If so... maybe the IAC needs adjusting. Crack the throttle screw open a little further... and see if you can get it to idle at all...

If that works.... you will need to get the IAC adjusted to around 25 or so on the IAC count....idling... and then re-adjust the TPS to around .46 or so idling. Everytime you move the throttle screw... it will change the TPS value at idle... and will need to be re-adjusted.

HTH

 

[fubar2578]

O.k. gentlemen the scanner I have is an Snap On MT2500 and yes it shows all the values of the sensors.


Tps reset to .44
Iac counts at 100 key on engine off
minimum idle was set during forced limp home mode with scanner
maf shows 6gm/s key on engine off with maf unplugged still shows 3gm/s
integrator 128
block learn 128
prom ID is 0
cts 168
iat 76

Car will idle when forced to limp home mode but not under normal computer management. No vacuum leaks.

Any questions just ask.

 

[jdpolzin]

LOL! Not around here. The rust belt is filled with mustangs and BB chevys. Anyone out there willing to lend out a loaner ecm and stock chip? Ahem...Jeremy? Got one around?

Hey Jesse!! Yeah I havent been hitting the boards much since I have been trying to prep for the baby! Been busy siding the house, replacing carpet, installing wood floors, build baby room stuff, painting, blah blah blah!!!!!!! Oh yeah, TRYING TO KEEP MOMMA HAPPY!!!!!!!!!!!!! :biggrin: !!!!!!!!!!!!!! If you need to borrow an ECM, you are more than welcome. Do you have a trailor??? If so, we could meet up at Jose's in Des Moines once I get this house sided. Should be done in a couple weeks. Heck, we would have 4 TR's to pick sensors from! Just a simple question, did you break your cam in? I know this isnt your problem but I just thought about that and two of my buddy's just wiped cam lobes on their new motors. One was running rich and he could figure out why, checked everything and it was the cam. I do agree with the others, triple check that IAC setting, if you need info on how to set and reset it, I can copy the GM manual for you. Otherwise, I know you said the chip is original and shouldnt be bad but you may have an issue with the ECM. I just sold my spare otherwis i could have hooked you up with it. -------Jeremy

 

[usetaboost]

Unfortunately no, don't have a trailer. I throw everything that fits in the back of my beater car-half the reason I don't want to get anything nice If I did gas would be a mother! Yeah I did break the cam in. Car didn't get hot or anything during break in, which is first for once. If it helps any the car hasn't ran any worse from day one. DOn't know if a compression test would tell anything but they all seemed to crank up nice and even when I did it. But if it was a bad cam why would it idle fine in limp mode? If it had a bad prom why wasn't there a code for it? I had a bad ecm in my TPI z28 and it ran like poop like this does until a certain rpm. Only thing with this is fan operates, gets code 12, lets scan pick up codes etc. My camaro wouldn't do that, except fan on all the time. But then if ecm is bad why don't it go to limp mode? Maybe it only does it when the chip goes bad, dunno. Damn you've been busy, do you sleep Jeremy? I guess if anyone has anymore suggestions or questions get them to fubar2578, he knows his stuff more than I do!

 

[usetaboost]

Oh yeah Jeremy forgot to tell ya, I will be coming to des moines in probably a month, whenever our "work trip" is. Going there saturday, hang out, have a few drinks, then hit adventureland sunday morning. Maybe we can all meet up then if it works for anyone, Won't have my car then, hopefully it will be in many pieces getting ready for paint, hopefully. I'll keep you posted on it in case u got time. I still need some stuff, mainly a hood and front bumper support, and there's a guy looking for a gn rear bumper adn fillers too if you come across stuff. Been trying to find a driver's door but no luck, don't wanna have one shipped either. Think I'll just have to bite the bullet and have a body shop put on a lower panel from postons. 40 bucks for the panel, 500 for labor I'll let u know on that ecm tomorrow. probably cost like 10 or so bucks for shipping? fk i don't know, LOL

 

[usetaboost]

Got a known good ecm. swapped everything over-guess what? Still don't idle. Started and died. Tried several times. Should I try my other chip or just take it to get hooked up on a scan tool again and see if there's a prom id?