 
     |
| High idle. (Page 1/1) |
|
sevulcan
|
FEB 27, 03:49 PM
|
|
Hi,
I purchased a 86 Fiero SE with a 2.8 v6 with a maual 4 speed. The motor was shot so I bought a reman motor and replaced basically all other parts, iac,egr,tps,map sensor,coil,distributor cap,rotor,fuel pressure guage,fuel injectors,changed the plastic vacuum lines with ss lines,relaced all gaskets etc, sent the throttle body out for a rebuild. When I started the car it idled at 2500-3000 rpms,so I thought I had a vacuum leak. Did the smoke test and checked everything ,couldn't find it. I blocked off the main intake on the throttle body in hopes the car would start and I could possibly hear where it was suckng air. It started and went right to over 4000 rpms I shut it immediately.
I am confused,don't know what to check. Any suggestions?
Thanks
Pete
|
|
|
|
Gall757
|
FEB 27, 09:43 PM
|
|
|
Big vacuum leaks are usually about the EGR system or the brake booster. Try pulling the hose for the brake booster and tape the hole on the upper manifold.
|
|
|
|
Patrick
|
FEB 27, 10:30 PM
|
|
Make sure the IAC tube from the manifold is properly inserted into the back of the TB.
|
|
|
|
sevulcan
|
MAR 01, 12:28 PM
|
|
Hi,
Thank you both for responding.
As it turns out the iac tube was not in the throttle body so I put it in and started the car, it went to over 5000 rpms,shut it immediately. I blocked off the throttle body and disconnected the brake hose at the top of the plenum and plugged it.Car wouldn't start. I put back the brake hose. Car wouldn't start. Unplugged the throttle body , car started but went to over 5000 rpms again. Hmmmm.
Pete
|
|
|
Patrick
|
MAR 01, 12:34 PM
|
|
Just for clarification... the engine won't run with the entire opening of the TB blocked off (if there are no vacuum leaks).
|
|
|
|
fierosound
|
MAR 01, 03:05 PM
|
|
| quote | Originally posted by Patrick:
Just for clarification... the engine won't run with the entire opening of the TB blocked off (if there are no vacuum leaks). |
|
Agreed.
But it certainly sounds like engine is acting as if throttle is wide open...
physically the throttle blade or the IAC valve is wide open
and/or TPS is sending full 5V signal to ECM
Who rebuilt this throttle body??
------------------
My World of Wheels Winners (Click on links below)
3.4L Supercharged 87 GT and Super Duty 4 Indy #163[This message has been edited by fierosound (edited 03-01-2020).]
|
|
|
|
Gall757
|
MAR 01, 05:01 PM
|
|
| quote | Originally posted by sevulcan:
Hi,
Thank you both for responding.
As it turns out the iac tube was not in the throttle body so I put it in and started the car, it went to over 5000 rpms,shut it immediately. I blocked off the throttle body and disconnected the brake hose at the top of the plenum and plugged it.Car wouldn't start. I put back the brake hose. Car wouldn't start. Unplugged the throttle body , car started but went to over 5000 rpms again. Hmmmm.
Pete |
|
you did your test a little out of order.......you still need to check the engine with the brake hose plenum hole plugged, and the throttle body open.
|
|
|
|