gm / ecm trouble codes

[Soundguy]

Back when I was in school, I had a mid 80's gm car ( pontiac sunbird ). I always was having to use the ecm test port under the drivers side dash to check the ecm codes to fix the car... seems like somehting was always wrong... anyway.. i remember you jumpered two lines,.. then the check engine woulf flash.. like code 12, etc 3 times.. then start flashing the codes.

I had aquired a code page from a mechanic but have long since lost it ( and got rif of the car ).

If I can locate the codes, I would like to pass them along to a friend who is trying to help out a disabled couple, trying to get their 88 pontiac fixed ( running poorly ). He's doing it as a favor as they are more or less indegent. I figure if he had the codes.. he could at least get a start on what they needed as parts.

Any help would be appreciated. If you don't want to post them, email them to me.. my email is as follows:

c.britton@worldnet.att.net

Thanks
Soundguy

 

[L3710GV]

You ground out the white wire on the test plug usually located bottom middle of dash, This puts the computer in diagonistic mode, It will flash the check engine light in code- Long is the ist digit short is the second digit. Like you said the ist 3 code sequnces are code 12 (1 long followed by 2 shorts-3 times) This says the computer is working and is in diagonistic mode, After code 12 is flashed 3 times the fault codes are flashed next three times each code. I do have the fault codes in a 1981 GM book which would use the same computer system, 1988 probably has some additional codes. Problum is it's many pages with explanitation for each code, too much typeing for my fat fingers--- If you could PM me with the fault codes I can look them up and PM the explanition. Also one thing to check-try is the fuel filter, On these old GM cars it's a small filter on the carb, When it partially plugs it leads to all sorts of running problums. I remember haveing the old wagon all loaded up wife and 4 kids to go up the hill to the snow, car would go awhile then start boging out and slowing down, pull over it would idle fine sounded ok /forums/images/graemlins/confused.gif turned out to be fuel filter. Hope this helps /forums/images/graemlins/laugh.gif

 

[Junkman]

codes are only part of the equasion.... We have a Ford Explorer that wouldn't idle at all in the cold weather. It would just race and then drop down to a very slow idle and then back up. Had it to 3 Ford dealerships and they all found the same code. Multi cylinder misfire, but couldn't isolate the problem. The first two wanted to just start replacing parts till they figured out the problem. I said no to that knowing that I would get buried with huge parts bills and not have the problem resolved. Went to the another dealer and ordered a block heater so if the block were warm, the engine would at least idle in the morning. Was talking to the parts guy and he said that he had the same problem with his Explorer. Knew what it was immediately and scheduled an appointment for the next day. Seems that the car had bad intake manifold gaskets and when it was cold, it would suck air into the intake manifold. Once it warmed up, the seal was then re established and it would run fine. During the summer months, there wasn't that much shrinkage of the metal to allow it to suck air. Codes are not the entire picture, but will sometimes help you to know where to look, but experience is more important than ever with todays cars.
Now if they can figure out the ABS problem, I will be real happy.... no trouble codes at all, but the ABS activates every time you come to a stop. This one also has everyone baffled and we have run out of ideas as to what is causing it. Even has the Ford factory guys stumped. /forums/images/graemlins/frown.gif

 

[jimg]

Was there no high pitched 'scream' when the air was getting sucked in at the gasket? My Ford truck did that...it sure was noisy! My mechanic knew right away what it was. He mentioned that letting the problem go unattended would have, in the short run, caused damage to the valves. He said something about running very lean and burning the intake valves.

 

[Junkman]

No noise and no problems with the valves. I believe that it has something to do with the fact that it is a 6 cylinder single overhead cam engine. Apparently there was a service bulletin on the engine at one time and the work was done under warranty, but the replacement parts were no better since it didn't resolve the problem the first time. Either that or they charged to do the repair and never did it. I don't know which one it is, but now it runs well and the problem is resolved. I think that the history showing that the engine had already had the modification done to it, was what threw off the two dealers that didn't know how to repair it. The third dealer didn't do a history check first and just attacked the problem first. They even commented that this was the first time that they had seen a engine need the same modification twice, which is what make me believe that the work wasn't done the first time, or was done with defective parts that were still in inventory.

 

[rlw]

Attached are the codes for GM vehicles '82 thru '95.
1996 and newer vehicles cannot have the codes read via the "jumper wire" method. '96 and newer have OBD II connectors and require a reader. The attached PDF pages are just pulled the pages from a GM OBD I manual located here: Code Manuals
There's a manual for Ford codes and new OBDII codes as well.

 

[Soundguy]

Thanks guys for the help.

I sent the info over to my buddy.. he went over there.. and got their problem squared away.

Turns out they didn't need the codes at all.. though some had been set..

It was a set of plug wires! And the dealer said it was a huge list of parts... go figure...

Soundguy

 

[fivestring]

I have a code reader and the code list.
I still drive a 1984 Monte Carlo.
If you still need the list of codes, PM me and I'll figure out how to scan or mail it to you.

 

[husbandangry]

okay here it goes I have a ford exp 02 and have noticeda whine when excellerating it and the engine is running fast. I happened to pull in the drive at the same time as my wonderful husband and he noticed and well he wasn't happy because out of warrany. It is very cold today and my baby sat in the wind all day i usually don't leave it in the open but i parked at work out so no one would park by me live in the northwest pa and am wondering if this problem is the same as the one you described and i am wondering what was the fix new mainifold????? please respond if you can i would appreciate it. I hate to be at the mercy of dealership and don't want to have hubby handle would like to know facts first. Thank you

 

[Junkman]

Your problem doesn't sound a like the problem that I had. My car was hunting for a constant idle speed. If it is a whine at higher RPM, it could be nothing more than the engine compartment is cold and that some of the fluids are setting up a harmonic vibration sound. I wouldn't be concerned unless it continues when the weather gets warmer. If it is running OK in all other respects, just don't be concerned unless it changes pitch or gets louder. Engines make strange sounds when they are cold and even when the engine is warm and the surrounding air is extremely cold, they can react differently that we are normally used to.

<font color="red">It would be nice if the moderator(s) would split this tread into its own because it is an entirely differant subject than the title... </font>