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| 1986 Fiero SE Won't Run (Page 3/7) |
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Spoon
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SEP 29, 07:28 PM
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I think I see your problem.
I take it that both of those IAC"s were removed with Engine-Off/Key-Off. When key is turned off the plunger withdraws from the port to allow idle air for the next start. Just turn the key to start, no need to push on the gas pedal.
The old IAC shows plunger extended which would block idle air when trying to start the engine, however working the gas pedal at same time as cranking may successfully allow the engine to start but would kill the engine once foot leaves gas pedal.
Since neither one seems to work correctly it may be time to acquire an automotive multi-meter and check the harness connector for the IAC to see if you're getting the proper electrical signals.
I could be all wrong about this and I welcome others to jump in and set the record straight.
Spoon
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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
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72and86
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SEP 29, 11:54 PM
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| quote | Originally posted by Spoon:
I think I see your problem.
I take it that both of those IAC"s were removed with Engine-Off/Key-Off. When key is turned off the plunger withdraws from the port to allow idle air for the next start. Just turn the key to start, no need to push on the gas pedal.
The old IAC shows plunger extended which would block idle air when trying to start the engine, however working the gas pedal at same time as cranking may successfully allow the engine to start but would kill the engine once foot leaves gas pedal.
Since neither one seems to work correctly it may be time to acquire an automotive multi-meter and check the harness connector for the IAC to see if you're getting the proper electrical signals.
I could be all wrong about this and I welcome others to jump in and set the record straight.
Spoon
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The top one is taken out of the car after sitting for 24 hrs, not run. The bottom new one is shown as it looks right out the box.
To recap; as it stands now, car starts after several attempts, idles very high a few seconds and dies. We haven't tried keeping it going manually by the throttle linkage... yet.
Ok so how do I test it and what reading am I looking for?
Steve
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Spoon
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SEP 30, 07:55 PM
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This link can help. Scroll down to "Idle Air Control Valve (IAC)".
http://www.gmtuners.com/tech/TPS_IAC.htm
ps: gmtuners is your friend...
Spoon
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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
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72and86
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SEP 30, 07:56 PM
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| quote | Originally posted by Rexgirl:
Maybe check for a crack in the EGR pipe (esp where it attaches under the plenum) ? |
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Without disassembly we sprayed Starting Fluid the area and no change in RPM. So without taking that apart it doesn't seem to be that. Tube from what I can see is nice and clean, no rot but cant see it all.
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72and86
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SEP 30, 08:00 PM
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| quote | Originally posted by ArthurPeale:
If it runs without being put into diag mode, but won't after being put INTO diag mode...I'd definitely check the timing. |
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Cant check timing if the car idles so rough and only by manual means working the throttle cable.
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ArthurPeale
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SEP 30, 08:43 PM
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You can check the roughest timing by manually rotating the engine until cyl 1 is at TDC, and verifying distributor installation.
Fine tune it from there
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72and86
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OCT 07, 10:22 AM
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Well a replacement TPS didnt do anything. Same. Engine starts hard then idles 3 seconds and dies. So my mechanic took the intake off looking for vacuum leaks. But we did find this...
 [This message has been edited by 72and86 (edited 10-07-2021).]
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72and86
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OCT 07, 11:43 PM
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Well the latest in the saga.
Cleaned out the entire plentum and EGR port (see pic above).
Checked EGR tube; spotless
Replaced TPS
Replaced Coolant Sensor
Removed cat and checked it.
Still same result, nothing changed. Car starts hard, runs a few seconds and dies. As before it can run if someone is constantly feeding the throttle. But let go and it dies.
Running out of things to replace and nothing seems to improve it.
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Patrick
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OCT 08, 02:49 AM
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| quote | Originally posted by 72and86:
Have plenty of fuel pressure.
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What is it... and how quickly does it drop when power to the fuel pump is cut?
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SemperFi18
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OCT 08, 03:06 AM
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Check all vacuum line connections. This includes them being inserted too far into their connectors causing an obstruction. Particularly the hose off the EGR solenoid, the hose goes to the firewall then tastes a sharp left, I had a large leak at the connection causing a similar issue. Check the PCV valve for free movement as well, you have to have a vacuum leak somewhere
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