'89 GTA 5.7 TPI with High Idle Issue
'89 GTA 5.7 TPI with High Idle Issue
Hello Everyone, I'm new to this forum but been around engines for quite some time. I'm not an expert but have already tried a couple things on this car and just want to get it to run good enough for the next guy/gal to enjoy.
Here's what I'm experiencing;
High Idle primarily at about 1500-1800rpm but will also jump up as high as 3k as I've been attempting to diagnose the problem. I haven't driven the car so there's been no learn time for the computer.
SES light flashes code 12 and continues to do so as long as I have the AB jumped. SES light will not go out while engine is running.
Plenty of noise coming from valve-train, almost like a solid lifter engine.
It also has a slight miss that I haven't attempted to diagnose but thought I'd adjust the rockers first and see.
Here's what I've researched and work I've performed;
1) Replaced the IAC and performed the install procedure to set initial idle. This was the only time I was able to get the car to idle below 1k but after I turned the key off and started it again, it jumped right back up to 1800 - 2k.
2) Checked TPS for voltage and that's good but can't seem to get a correct resistance reading.
3) Set to factory timing at 6* BTDC with EST disconnected
4) Replaced Cap/Rotor
5) Replaced PVC valve and checked brake booster for leakage, none found
6) Replaced O2 sensor
7) Sprayed carb cleaner all around intake and hoses, no leaks found
8) Has a crappy after market intake hose on it with a cone filter at the end. I plan to find an original or equivalent to replace it with. Seems the wires/hoses that went to the original air cleaner box have all been disconnected and plugged.
Any ideas and/or questions welcome. I'm sure this has been encountered here and I searched the boards and have used some of the info to diagnose this car but I'm kind of stumped and don't want to continue to throw money in the way of parts at it if I can help it.
Thanks, Jim
Here's what I'm experiencing;
High Idle primarily at about 1500-1800rpm but will also jump up as high as 3k as I've been attempting to diagnose the problem. I haven't driven the car so there's been no learn time for the computer.
SES light flashes code 12 and continues to do so as long as I have the AB jumped. SES light will not go out while engine is running.
Plenty of noise coming from valve-train, almost like a solid lifter engine.
It also has a slight miss that I haven't attempted to diagnose but thought I'd adjust the rockers first and see.
Here's what I've researched and work I've performed;
1) Replaced the IAC and performed the install procedure to set initial idle. This was the only time I was able to get the car to idle below 1k but after I turned the key off and started it again, it jumped right back up to 1800 - 2k.
2) Checked TPS for voltage and that's good but can't seem to get a correct resistance reading.
3) Set to factory timing at 6* BTDC with EST disconnected
4) Replaced Cap/Rotor
5) Replaced PVC valve and checked brake booster for leakage, none found
6) Replaced O2 sensor
7) Sprayed carb cleaner all around intake and hoses, no leaks found
8) Has a crappy after market intake hose on it with a cone filter at the end. I plan to find an original or equivalent to replace it with. Seems the wires/hoses that went to the original air cleaner box have all been disconnected and plugged.
Any ideas and/or questions welcome. I'm sure this has been encountered here and I searched the boards and have used some of the info to diagnose this car but I'm kind of stumped and don't want to continue to throw money in the way of parts at it if I can help it.
Thanks, Jim
Joined: Oct 2001
Posts: 12,213
Likes: 1,140
From: Il
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: '89 GTA 5.7 TPI with High Idle Issue
Sounds like a vac leak but post up a picture of the engine compartment if you can.
Re: '89 GTA 5.7 TPI with High Idle Issue
If you see anything out of place in there, let me know as I'm not real familiar with this car. If you need close ups of anything I can also provide that as well.
Looks like someone also replaced the Alternator and EGR recently. I replaced the serpentine belt.
Thanks, Jim
Joined: Dec 2004
Posts: 16,736
Likes: 993
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: '89 GTA 5.7 TPI with High Idle Issue
Are the injectors from southbay or fic. Fic uses duel o rings to seal the injectors from vacuum leaks. Southbay has a glued/presses on fit pintle extension.
Re: '89 GTA 5.7 TPI with High Idle Issue
No idea what brand they are, they must have been changed by the previous owner. Can you tell by the pics I provided ? I sprayed all around the injectors with carb cleaner and no change in idle so I don't think they're leaking any air.
Joined: Jan 2013
Posts: 328
Likes: 7
From: Gresham Oregon
Car: 1985 Z28 & 1997 Z28 SS SLP
Engine: Sbc 305 TPI & LT1
Transmission: 700r4 and A4
Axle/Gears: 9 bolt Posi 323 & Posi 323
Re: '89 GTA 5.7 TPI with High Idle Issue
Here are a couple pics. Please excuse the disaster of an engine bay this thing has, the previous owner(s) were real hacks. I'll be correcting the air induction and restoring the engine bay to a presentable looking condition but would like to get the car to run properly first. Any suggestions on an aftermarket cleaner box would be great, otherwise I planned to source an original box system from a local pick-a-part yard unless someone here wants to part with either for a good deal.
If you see anything out of place in there, let me know as I'm not real familiar with this car. If you need close ups of anything I can also provide that as well.
Looks like someone also replaced the Alternator and EGR recently. I replaced the serpentine belt.
Thanks, Jim
If you see anything out of place in there, let me know as I'm not real familiar with this car. If you need close ups of anything I can also provide that as well.
Looks like someone also replaced the Alternator and EGR recently. I replaced the serpentine belt.
Thanks, Jim
Joined: Dec 2004
Posts: 16,736
Likes: 993
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: '89 GTA 5.7 TPI with High Idle Issue
Did the idle go down when you set the minimum idle speed ?
If so you could have a bad ecm commanding the iac out.
If so you could have a bad ecm commanding the iac out.
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Re: '89 GTA 5.7 TPI with High Idle Issue
No recovery tank, car came to me on a trade like this. I need to source on of those as well so if anyone has any of the original parts I'm missing for a reasonable price, please let me know as I plan to visit a local pick-a-part when the weather dries up a bit and wouldn't mind not having to make the trip.
Re: '89 GTA 5.7 TPI with High Idle Issue
I plan to perform this procedure once more and document exactly what happens as the first time was just familiarizing myself with the procedure and I didn't pay too much attention as I thought I fixed it. Any tests you recommend or what to pay close attention to while I perform this install procedure on the IAC again that you can suggest ? I don't want to just buy an ECM on the hopes it's the problem, just to find out it's not as others have. Any test I can perform to eliminate the ECM ? Or am I at the point of bringing it to a shop for another set of eyes and digital diagnosis ?
Thanks, Jim
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