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post #1 of 7 (permalink) Old Apr 22nd, 02, 07:28 AM Thread Starter
Join Date: Apr 2002
Posts: 6
I have a 91 Camaro RS. I've been unable to get it running for about two weeks. At first, it would run until the gas was pressed. Now when i crank it, it will either run in idle fine and then conk out when put in drive, or it won't start at all. In the past two weeks, I've put on new ignition switch, spark plugs, wires, rotor, cap, O2 sensors, cleaned out throttle body, cleaned out catalytic converter, new air filter and new fuel filter. Also I had just had new starter put on. I still get problem codes with service engine light. These codes are 41 and 42. Does anyone have any other suggestions. I really don't want to pay to have it towed somewhere. A guy that I talked to at pep boys said it could be the ECU. Anyone know where this is on the engine and/or how much that would be? OR think it could be something else. Thanks for any help.

[This message has been edited by jess235578 (edited 04-22-2002).]
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post #2 of 7 (permalink) Old Apr 22nd, 02, 03:45 PM
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Join Date: Nov 2001
Location: Oxford Pa.
Posts: 503
If I remember right 41 and 42 are ignition codes and the engine will still run with those present (EST codes. I think)
Does it have spark at the spark plugs?
If spark is present, I would have the fuel pressure checked.
Lets get a little more info...
What engine is it?
How did it run before all this started ?
The ECU the PepBoys Guy is referring to is probably the ECM or Electronic Control Module, this is the "computer" that controls the Fuel and Ignition systems on the engine...and I wouldn't just throw one at it yet........
Repost with some more info...
(My 1st thought is fuel pump, but I would check the pressure before just guessing...)
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post #3 of 7 (permalink) Old Apr 23rd, 02, 04:03 AM Thread Starter
Join Date: Apr 2002
Posts: 6
Hey. Thanks for your response. It's a 3.1 V6 (for now anyway..hehe). There is a spark at the spark plug. The oddest part is that it ran perfect before this other than the starter needed to be replaced. When all this started, it would hesitate when the gas was pressed and then the RPM would jump by itself. Now it's not even doing that. I did forget to mention that there is a strong gas smell when we can get it cranked. You can smell exhaust also but I'm getting that replaced hopefully next week sometime, it's all rusted from the muffler back. So you think I need to check fuel pressure next?
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post #4 of 7 (permalink) Old Apr 24th, 02, 04:11 AM Thread Starter
Join Date: Apr 2002
Posts: 6
Ok. When checking a few things last night I may have found what's wrong with it. I had to create a vacumn leak in order for the car to ever start. So it's getting way too much fuel. The only code I'm getting now is a 41 which is "incorrect prom/defective ECM". Prom is installed correctly and number matches what's in the books for my car. From what I was told only a dealership can test and sell proms. Does anyone know if this is true and around how much this should cost?
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post #5 of 7 (permalink) Old Apr 25th, 02, 04:19 PM
Senior Tech
Join Date: Feb 2000
Location: Waldorf,Md,USA
Posts: 176
Does the car have a Mass Air Flow sensor?

Leo Paugh
MCC #017

If you have no fear, you're not going as fast as you could.
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post #6 of 7 (permalink) Old Apr 25th, 02, 04:50 PM
Join Date: Apr 2002
Location: Milwaukee WI USA
Posts: 5
a new ecm would be right around $100.00 a new prom would be about the same if you are going to replace the prom you might as well chip it and get some more performance out of it you can call summit racing at 1-800-230-3030 for the proper chip(prom)Hypertech makes them due to the codes you have and without knowing fuel pressure it sounds like an ecm problem when you change the starter next time remember to disconnect the negative battery cable and you could have probably could have avoided this problem. you might also check the ecm ground make sure it is clean and tight it should be located behind the left side headlights. (DISCONNECT THE NEGATIVE BATTERY CABLE BEFORE MESSING WITH IT PLEASE!) I used to work at a GM dealership and don't know of any way to bench test a ecm or prom prior to 1996 when obd 2 came into play we would just swap in a new ecm and try it remember the ecm you will get from the parts house/department will not have a prom in it you have to swap the old one generally the prom chip doesn't go bad so I geuss I would try the ecm first (ALWAYS REMEMBER TO DISCONNECT THE NEGATIVE BATTERY CABLE BEFORE MESSING WITH THE ECM)if the car is running rich the quad driver in the ecm is probably bad this is common quad drivers are not replaceable they are part of the ecm.
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post #7 of 7 (permalink) Old Apr 26th, 02, 04:39 AM Thread Starter
Join Date: Apr 2002
Posts: 6
Well I ended up replacing the ECM and prom and it is running now. I'm getting my exhuast done today so hopefully after that everything will be fine for a little while. I just put the stock prom in from a dealership because I don't plan on keeping that engine for too long. Anyhow, I just wanted to say thanks for your help. I'm really glad I found this site just getting started out and everything. Thanks.
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