Stalling '85
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Joined: Sep 2005
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From: Calgary '85 Z51 coupe
Stalling '85
Car was running great until today. Now it starts but it tries to idle around 450 rpm and dies.
If I hold the accelerator down it will run but it sounds like it is missing/running rough.
There are no codes!
I checked the distributor cap for moisture, the plug wires were on tight, checked the fuse for the cold start injector; the maf, tps and iac connections seem fine.
What else should I look at?
If I hold the accelerator down it will run but it sounds like it is missing/running rough.
There are no codes!
I checked the distributor cap for moisture, the plug wires were on tight, checked the fuse for the cold start injector; the maf, tps and iac connections seem fine.
What else should I look at?
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
If it only happens at idle, I would check/clean the IAC and TB if it hasn't been done in a while. When the IAC gets carbon filled or faulty it will not throw a code. From your discription...this is where I would start.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
Also the TPS could be out of adjustment. Will need to check volts (.54v). The CSV fuse, switch, circuit, or connection being bad/faulty would make it longer to start when the engine temp is 90*f or less.
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From: Calgary '85 Z51 coupe
Originally Posted by RRT vette
If it only happens at idle, I would check/clean the IAC and TB if it hasn't been done in a while. When the IAC gets carbon filled or faulty it will not throw a code. From your discription...this is where I would start.
Have checked the CSV fuse, I guess the connection and checking the tps voltage would be next.
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From: Calgary '85 Z51 coupe
Yes, beware of flying rotors - I just checked that a few weeks ago so that can't be it. Had the plugs out when I did the valve seals so they should be good.
My buddy is on holidays so no access to good things like fuel pressure testers, I guess I will see if I can muddle through it.
My buddy is on holidays so no access to good things like fuel pressure testers, I guess I will see if I can muddle through it.
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Thread Starter
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Joined: Sep 2005
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From: Calgary '85 Z51 coupe
OK now I'm frustrated.
Spent most of today trying to get this running again.
Changed the fuel filter.
Checked vacuum lines.
Bought a fuel pressure gauge and checked the pressure and it is fine for '85 (35-39 psi).
Checked TPS.
Took out IAC and cleaned pintle.
Cleaned all plugs. Put in a new coil (just because I had one).
Put in a new IAC.
No codes. Won't run.
Spent most of today trying to get this running again.
Changed the fuel filter.
Checked vacuum lines.
Bought a fuel pressure gauge and checked the pressure and it is fine for '85 (35-39 psi).
Checked TPS.
Took out IAC and cleaned pintle.
Cleaned all plugs. Put in a new coil (just because I had one).
Put in a new IAC.
No codes. Won't run.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Is it still doing the same thing? Does it crank at all? If you haven't had the ICM tested, it might be a good thing to do so. Is there spark on all 8 cylinders? Have you checked timing or set minimal idle lately? Just some more thoughts.
You have fuel pressure at the rail. How old are the injectors?
You have fuel pressure at the rail. How old are the injectors?
Team Owner
Joined: Jan 2003
Posts: 20,304
Likes: 240
From: Summerland B.C. Canada
Originally Posted by zoro
OK now I'm frustrated.
Spent most of today trying to get this running again.
Changed the fuel filter.
Checked vacuum lines.
Bought a fuel pressure gauge and checked the pressure and it is fine for '85 (35-39 psi).
Checked TPS.
Took out IAC and cleaned pintle.
Cleaned all plugs. Put in a new coil (just because I had one).
Put in a new IAC.
No codes. Won't run.
Spent most of today trying to get this running again.
Changed the fuel filter.
Checked vacuum lines.
Bought a fuel pressure gauge and checked the pressure and it is fine for '85 (35-39 psi).
Checked TPS.
Took out IAC and cleaned pintle.
Cleaned all plugs. Put in a new coil (just because I had one).
Put in a new IAC.
No codes. Won't run.
1st Gear
Joined: Jun 2006
Posts: 1
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Similar "No start" problem with '85
I have a similar problem with my '85. Started running rough one evening and had to keep RPM's below 2800 to get home. New plugs, coil, wires, fuel filter, clean TB, fuel pressure 45 psi (with minor drop when ignition turned off), rebuilt fuel pressure regulator, NO CODES. Briefly runs on starting fluid. If I restrict the fuel return line at the tank, car starts and runs....until I remove the restriction, then it stumbles and dies.
Clogged Fuel Injectors? I would like other's opinions before tearing off the TBI and fuel rails... but it does look good sitting in the driveway!
Clogged Fuel Injectors? I would like other's opinions before tearing off the TBI and fuel rails... but it does look good sitting in the driveway!
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From: Calgary '85 Z51 coupe
Haven't done much on this lately.
I have tried another MAF unit--no change.
Also tried another chip--no change.
I will try disconnecting MAF but there have been no codes so I would be surprised if that makes a difference.
I have tried another MAF unit--no change.
Also tried another chip--no change.
I will try disconnecting MAF but there have been no codes so I would be surprised if that makes a difference.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
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From: seattle WA
Have you checked your timing? And since Agent86 mentioned it...were you the guy who had the rotor come apart? if so, I'd take a good look at the ICM and pickup coil connections, also I hope you inspected the dist. cap.
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From: Calgary '85 Z51 coupe
Agent 86 had the bad rotor, not me.
ICM tests OK. Dist cap and rotor look good. Plug wires are correct. Replaced the coil already.
I would like to check injectors and timing but the battery is dead now. Put it on a trickle charger and will see what happens tomorrow.
Oh, I disconnected the MAF and it made no difference.
ICM tests OK. Dist cap and rotor look good. Plug wires are correct. Replaced the coil already.
I would like to check injectors and timing but the battery is dead now. Put it on a trickle charger and will see what happens tomorrow.
Oh, I disconnected the MAF and it made no difference.
Thread Starter
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From: Calgary '85 Z51 coupe
The car has been running fine for about a week. I didn't post anything because I was superstitious that it would act up again. The best I can figure is it was possibly 1 plug wire, 1 hairline crack in a plug and an incorrect TPS setting. Once I borrowed a digital tester I could see the TPS was off by .3 mV.