Hi guys! So I'm really hoping for some help here...I'm about ready to throw this car out! I'm suppose to go tonight to pickup the girlfriend for a 1st date...and you would know the trans am decides to act up....on to the problem.

Ok so stay with me here. Me and my step dad we're chasing a squeal coming from a pulley. We had taken the belt off and were in the process of putting it back on. The wrench slipped off the Tensioner pulley and sparked with the battery...So anyways get it all put back on and crank up the car...it instantly starts to idle to and hold at 2K RPM...Check engine light comes on showing IAC P0507...I have tried disconnecting the battery, letting it sit, pulling the "computer" fuses...disconnecting the actual computer itself...still it idles way to high...even tried the IAC relearn procedure...The odd thing is the dome lights will now randomly come on and off when they feel like it. The key as well wont release it gets "stuck" about 1/3 away from the off position and you have to force it back to get it to release and force it forward to "unstick" and release to start the car....this sounds like a seperate problem from the idle issue...funny how it just had a massive meltdown yesterday...it could not have picked a worse time to start this....ANY HELP is greatly appreciated...I'm thinking the ECM got fried possibly when the wrench sparked on the battery terminals?? We had took it on a test drive and the oil pressure only held 20...we turned right around and brought it home...left the battery disconnected for the night, idle problem still present, oil pressure seems good at 40...Mind you before the wrench touched the battery the car worked perfect except a squealing pulley...

Car is a 1998 Trans AM LS1 114K

 

I love the LS1 but this electrical stuff is over my head. I'm having what I believe is electrical problems with mine too and it's such a pain. Maybe if you have a friend with a f body you can plug in their ECM and give it a shot.

 

I hear that!!!! You know the kicker? We have a 97 F-body LT1...one year away haha

I bought a TPS and Idle Air Control sensor...it's actually worse now...instead of 2K idle I'm not at 3K...I am 99% sure its the computer now...Finding one seems to be another story being a 98...I found all kinds of 99-02's but not any 98's locally...time to expand the search to the internet I guess...lol...ughhhh...

 

I had a 97 F-body... the opti was giving me problems here and there and I thought the LS1 would be less of a headache but man was I wrong. Did you check to see if it's a vacuum leak? And if you wanna sell the TPS I'll buy it lol i think I need one to fix my car

 

We've had problems with Opti with it as well...currently it's parked because it keeps...absorbing water....like as in massive puddles get in it after it rains out...we have no idea where its coming in from as the top of the car is dry as a bone...lol

I would sell it to you but I took it back to the parts store after it didn't work!! lol

Although this is a bit interesting...we took out the IAC out and turned the ignition to "ON" the plunger didnt move at all...So we manually moved the plunger and adjusted it manually a few times...It now idles where it should and drives good...No check engine light.

...However...my oil pressure at idle is 20 and at running temp at 55MPH is only 30...now if you rev it up the pressure will go up to or over 60....it just seems to low...no??? The guage is also very jumpy as well since the old wrench sparked off the battery...Any ideas?

The second issue which didn't happen until the wrench sparked the battery is the ignition is locking about 1/3 away from going to the release, or off position...here's where it takes a strange twist...if I do the IAC relearn for the computer the key will release and work just fine...after a certain amount of time...or startups the key locks again....I never had this issue until the battery and wrench met...Any ideas at all??? I dont want to throw money at it...does the ecm control anything with this? Maybe some type of security feature not working right?????

 

Sounds like you may have a bad ground somewhere (wire got fried).

 

Are you sure you didn't knock the PCV hose off while working on it? The code you posted up basicly is telling you the IAC is working but the engine is running too fast. Look for a vacuum leak.

 

^ that makes sense, do what he said (can you hear a loud air leakage sound...?)

 

Thats what I had been coming across when I have been researching this problem, however I really don't hear any leaks, the motor sounds really good right now. I'll check it over again when I get back home though! Thats the thing, it idles like a bat outta you know where before we manually adjusted the IAC plunger...Is it possible to be a computer goof up? or is that a safe thing to eliminate? I hate problems like this where there's little to go off of! lol

I'm still trying to figure out why the ignition wont release the key unless I do the IAC relearn, then for some reason during that process it starts working fine until a certain amount of key cycles and it starts locking the ignition again....

....sometimes I just cant even with this car! LOL

 

PCM is not necessarily eliminated... altho, it is robust and typically does not fail.

 

Always cover the battery with a towel when working near it with wrenches.

With that said.....

Sounds like the PCM may have gotten damaged. Pull the two strip covers off the pin rows and look to see if you see any burnt pins or burnt pin holes. I had this happen once and it was the MAF pin......so it caused my TPS, IAC, Temp sensor and IAT sensor to all read incorrectly....which in turn made my engine run like ***......

Got a new PCM and it was fixed. But I did see that single burnt pin in the PCM pin row hole.

.

 

Hey I learn everything the hard way I guess!! haha
Yes, I will be doing that every single time now, no doubt!
I'm really really leaning toward the pcm...its just seems hard to find the 98's without paying a absurd price...I'll take a close look at it when I get back home, as well as any possible vacuum leaks...I'm leaning hard towards the pcm tho...Everybody cross your fingers! and if anybody has a spare 1998 trans am pcm laying around...let me know!! lol

I really do appreciate all the help so far guys!! Thanks!!

 

I had the IAC react really slowly on my LS1 once, after I had done some intake work. Ended up removing it, pulling the plunger out slightly, and reinstalling it. I know the computer would have closed it eventually, but it was a little annoying to my neighbors having my car idle at 2k rpm until it warmed up...

 

I think I might have a slow computer as well! I got off work and drove about 60 miles, mix of interstate, city, all that. It seems to start and idle like it should...has all the power it use to have...it still seems like it should have a bit more pep say when your going like 40 and hit the throttle...but I think all in all its running good...

After driving that far the key/ignition even started acting like it should...for a about 3 key cycles...then it "locked" itself again....This is a stupid questions but I have to ask it...Is there anything electronically controlled by the computer that would cause the key to lock and not wanna release? And then randomly start working again? Say maybe this is a different issue that has nothing to do with the original...What would cause something like this? I'm not sure how to trouble shoot a problem like this...never have had a issue like this...I'm sure its something dumb haha

 

That sounds like a BCM related problem.

 

ehhhh I hope not! lol...I was just out there messn with it a bit...I got a big piece of info for you guys...It turns out you can put the gear selector in any gear, anytime...Key in the ignition, key in my pocket, ignition on, ignition off...I'm no mechanic but in park with the key off that sucker shouldn't move from park I wouldn't think! haha...this is a automatic car...So could this be a ignition switch? (I hope so, looks like its only $30 lol)...any ideas guys?


EDIT:

So searching i found this, it has some interesting info in it, and is exactly the same symptoms as my car...Tomorrow I'm gonna check it out!

https://ls1tech.com/forums/general-m...on-t-lock.html

EDIT:

Ok so the park lock cable was the cause of the key "binding" up...That car still is lacking the power it use to have....I unplugged the Mass air flow and obviously set off the SES light...but now difference in how the car ran...also unplugged the IAC and again no difference in the way the car ran...Whats going on here? I mean without the mass air flow shouldnt the car be running very bad or not at all?