1985 Grand Am

[Tech II]

You can go into any GM dealership....bring your VIN #.....on the computer, they can look up "vehicle build" with your number...it tells them the ECM number for your vehicle and also the latest PROM # for the ECM, based on your VIN....

[jayrider75]

Ok thanks, I'll check it out, hope it goes good.

[jayrider75]

Purchased a ecm from eBay, problem solved, thanks for your help.

[Tech II]

Good for you....you kind of lucked out....mid 80's to early 90's ECM's were a real pain.....

Back in the day, when you had a bad ECM, you had a yellow tag, and were suppose to write down all the symptoms and codes(if set), and return the ECM with the tag, and SUPPOSEDLY, the symptoms/codes were fixed, and then the unit was "refurbished" and sold as a rebuilt.....

During that period, I had rebuilt's, right out of the box, that wouldn't even start the car.....in some cases, the rebuilt ECM took care of the original problem, but created a new problem.....so consider yourself lucky.....

[jayrider75]

Hi, I've got the car running great. Except the o2 sensor will go on as I start to drive, not at idle, even if I idle around the block a few times. I'm thinking the wiring could be the issue. I've replaced the o2. Same results as when I put the other one back as well. The wiring is pretty ugly, some loose,crappy repairs. I'm trying to find a colored wiring diagram, I don't think there is one for this car in particular. I've done qiute a bit of searching. I'm going to school in automotive so I have access to ALL DATA and Mitchel and still not detailed. I know there might possilbly sites that I can spend money on, I am on budget. I'm sure finding a wiring harness is probly near impossible. If I was to be lucky enough to find a harness that is auto would I be able to use it and just close up auto wiring? Except there is 2 wire sensor coming out of manual. PLease let me know, it's been 3yrs. and I'm ready to roll! Thanks.

[jayrider75]

Hey Tech II , still working on my Grand Am 2.5 run great except high idle. I've checked the IAC for function, works fine. TPS seems to be ok. Fuel injector cone seems good. My professor thinks it may be myTB throttle plate is worn, loose, meaning from return spring side to the tps. I do have a body with all of that in tact. The whole thing is I've ran it for a while before I took it on the road, to get some miles on it and to pre smog.The thing just decieded to high idle since. I've delt with this before but all my "fixes" hasn't worked.It's been 4 years, I've got 460,000 going for 500,000. My next is to change out TB. Hope to hear from you. Thanks.

[Tech II]

If you are sure, the IAC is working correctly, a high idle is usually caused by a vac leak.......

I don't know if you have access to a scan tool that reads OBD I data......you would look at IAC counts......at normal idle, should expect to see 10-15 counts......if the idle is too high, the ECM would be commanding the counts low(closing the IAC), to almost zero....if this is the case, and Idle is still too high, check for a vac leak with carb cleaner.....spray around the base of the throttle body(gaskets are known to leak).....also around the intake gasket....if you spray, and there is a change in idle, you have found your leak....

[Blue Bowtie]

That worn throttle shaft could be causing the plates to stick in the bores when they close. The symptom of never getting the idle to repeat reliably is as old as carburetors, and can be solved by bushing the shaft. Short of that, a replacement (i.e., not worn) TB could solve it.

The procedure will be similar to this:

http://www.automotiveforums.com/vbul...d.php?t=966191

[jayrider75]

Well I went to replace my tbi, and the first thing I went for was the fuel lines. First was nice and tight , second was a little loose so I figured I should tighten it before I go any deeper, even after I had spayed around tbi a few days ago and no change in idle. After the tighten it's running great! THanks again for the help!

[jayrider75]

Hey, new problem has arised..I recently replaced my TBI because of vacuum leaks in between shaft/blade.So the engine runs fine , idles great drove it for almost 2 weeks and now the code 35 is showing up I believe it's IAC valve. I've ckecked the ohms and are within spec , replaced connector just cause the old one was in bad shape. It only comes on when at idle ,stop light, traffic. I've takin the valve out of tbi and connected dlc to see movement and the thing moves. This code did not show up with other old tbi. Please let me know if you have any ideas..thanks

[Blue Bowtie]

Relearn?

[Tech II]

Blue, should have relearned(just by driving), by now, 5 months later.....but I guess it couldn't hurt to try, since it is a simple procedure....

Most techs had a tool, that attached to the IAC connector and you could manually open and close the IAC to check idle operation.....

Was this problem there before you replaced the IAC connector or after?

[jayrider75]

E brake(parking) issue. my ebrake handle no longer engages. It has barely been working for quite some time, and now I have nothing, I've replaced my rear brake shoes, new hard ware, the kit didnt have those little kind of flat springs for the bar that goes on the one side so what I have there is broken springs and are completly gone.I've adjusted cable, shoes...worked for a few days now nothing.Its a manual so ebrake is pretty importantIf the cable is streched and needs replaced I,ve never replaced one of these so if any one has some info on that I'd appeciate it. Thanks.

[Tech II]

Well, can you see the main cable move when the ebrake is applied?

Actually you can just grab each secondary cable going to each drum, jack up a wheel, and just pull on the cable into the drum, and then try and rotate tire.....

If the tire still rotates, the problem is inside the drum.....

If the tires lock when you pull on the cables going into the drum, and the main cable moves when you pull on the lever/or push ebrake pedal, then the cable could be stretched......based on your year, you might not be able to move the adjuster because of age/corrosion....and it might have to be replaced....but you can try soaking the adjuster with something like PB Blaster, to try and loosen the adjuster.....

[jayrider75]

Ok, so I did pull on each cable and the main, i was able to adjust cable I maxed it out. One side kind of works. the other does nothing. I also puled on main and not to much happend. I have recently replaced hardware for drums, one problem with that is it didn't come with the springs for strut, those were toast, I was told that wouldn't be the problem.