Hard Start with High Idle

Asked by May 20, 2011 at 10:03 PM about the 1984 Pontiac Fiero SE or Indy

Question type: Maintenance & Repair

1984 Fiero SE Automatic.
This one is driving me crazy!  I has spend about $1,000 in parts and repair time at a local shop.  Car always had a bit of a high idle (about 2,000 RPM), but I could live with it.  About a week ago, the car began having problems starting.  It turns over fine (battery new) for about 30 seconds, then finally fires up and idles (although 2,000 RPM), and runs just fine.  Then as the week went on, the car took longer and longer to start.  Now it takes a good couple of minutes to get started. It has been at the shop for 2 days, and they can't figure it out either.  Fuel pressure test is 42 psi.  I have tested and or checked: MAP, MAT, IAC, engine temp sensor, cap, rotor, spark plugs, plug wires, EGR/EGR tube, Ignition module, and checked for vacuum leaks.  I have replaced (for the heck of it): MAP, IAC, engine temp. sensor, cap, rotor, ignition control module, and plug wires.  I am getting an IAC error from the ECM, but assume it is a false error because the computer can't bring the idle down, so it thinks the the IAC is bad.  Even ignoring the high idle, it still has a major problem starting.

I verified that each plug is getting spark by connecting the timing light on each wire.
I then connect the timing light on the output of the induction coil, and cranked the engine.
I get consistent flashing (good sparks) from the timing light.  After a minute of cranking, I smell plenty of gas fumes from the exhaust tips.

So, I get gas to the engine, good sparks from the ignition coil, but still takes a long time to start, and then idles a bit high (2,000 RPM).
Any ideas?  Something I haven't thought of?

3 Answers

1,935

Sounds like you might have some intake leak, or some other gasket thats not sealing correctly. Get some carb cleaner and spray it around the intake or anyother place that you might think air might be getting in.

1 of 1 people found this helpful.
20

have you done anything with the tps? throttle position sensor? i had a high idle problem with my 84 2.5. changed the tps and it went away

2 of 2 people found this helpful.
10

Had the same issue. Replaced tps, iav, map sensor....nothing helped. Looked for air leaks....none. egr ok. Moved the bundle of wires along the left side of the engine. And the rpm suddenly dropped to normal. Check for shorts as well. With all that my tps really needed to be replaced so not all wasted time. Good luck and long live the fiero.

1 of 1 people found this helpful.

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