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High idle 2000rpm

Printed From: West Coast Fieros
Category: Technical Topics Forum
Forum Name: Technical Questions and Discussions
Forum Description: Got a technical question about your fiero? ask it here.
URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=1068
Printed Date: 23 November 2024 at 11:27pm
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Topic: High idle 2000rpm
Posted By: swashburn
Subject: High idle 2000rpm
Date Posted: 15 December 2008 at 12:55pm

I have replaced map,mat,iac,tps, tps connector, iac connector, checked and replaced grounds and tested electrical everything checks out. Could this be a timing issue. I have reset the timing several times. The 1986 se 2.8 v6 drives fine but I can't get the idle to drop.

I must be missing something. Help.

P.S. can I remove the water lines going to the throttle body they are always in the way.




Replies:
Posted By: Patrick
Date Posted: 15 December 2008 at 2:26pm

Have you checked for vacuum leaks, especially at the EGR tube? It usually cracks.

In regards to removing the coolant lines that go to the TB, yes, this is a common procedure.

 



Posted By: Capt Fiero
Date Posted: 15 December 2008 at 3:07pm
  Totally agree with Patrick on both counts, the EGR tube can be cracked and you won't hear the leak due to the wrap that is around it.  The Throttle body coolant lines are also common to remove, I have removed them on every V6 I have ever worked on and owned.   They were only installed for the 1 in a million chance of a TB icing up.  Which in the 400,000+kms of driving Fiero's I have never had happen, and I have never ever heard of it happening to anyone else.   Just when you remove the lines, you have to cut the MAP sensor bracket and bolt it directly to the side of intake. Then cap off the coolant lines at the coolant filler neck.

-------------
Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: swashburn
Date Posted: 15 December 2008 at 3:14pm
I have a new egr and braided tube. As soon as it warme up a little I will take the water lines off. Back to the the high idle. Capt told me to check for bad wiring or ground. I have ground and replaced the connector with a butt splice. maybe the butt splice is creating to much resisitance ? Would fuel system cause the high idle ? Or maybe just a bad distributor module? I have noticed that it's running a little rich. I will check the egr tube it's brand new. I may just sill it off.


Posted By: Patrick
Date Posted: 15 December 2008 at 3:21pm

Pull off the big hose from your air filter to your TB. See the air passageway at the bottom of the inside of the TB? While the engine is running, put your finger over the end of that passageway. The engine should stall as your finger is now blocking all air that the IAC is able to allow through. If your engine doesn’t stall, I’d say you have a vacuum leak somewhere.

 



Posted By: Capt Fiero
Date Posted: 15 December 2008 at 3:42pm
Only thing that I have heard mention and this is probably the simplest fix if that is the problem.  Do you know if anyone has messed with the min idle bleed screw?    There is suppose to be a metal cap over it, but if someone removed the cap and cranked up the idle, the IAC would not be able to compensate for it and it would set an IAC error after only a few mins of driving.  The set screw I am talking about is on top of the throttle body, its in the bottom of a hole about the size of a #2 pencil eraser.   Turn clockwise to increase idle speed, counter clockwise to reduce idle speed.

-------------
Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: swashburn
Date Posted: 15 December 2008 at 4:08pm

Patrick the line you are talking about is the line from intake to the back of the tb ? and capt I didn't know that and it hasn't been messed with that i know.

 



Posted By: swashburn
Date Posted: 15 December 2008 at 4:23pm
patrick now i know what you are talking about i will do tomarrow thanks.


Posted By: Patrick
Date Posted: 15 December 2008 at 4:31pm

Originally posted by Capt Fiero Capt Fiero wrote:

Do you know if anyone has messed with the min idle bleed screw? There is suppose to be a metal cap over it...

Dave didn't come out and say it, but I'm sure he'll agree that if the metal cap is still over the screw, don't be messing with it!

Leave it alone (if it hasn't been touched) as it's a complete hassle trying to adjust it properly again.

 



Posted By: swashburn
Date Posted: 15 December 2008 at 4:44pm
Okie Dokie. I wonder if i pull the egr tube if i can see the crack if there is one by shinning light down the tube.


Posted By: Patrick
Date Posted: 15 December 2008 at 5:10pm

Here's what mine looked like. Pictured is the end which was connected to the underside of the intake plenum.

I didn't need to use a light to find the crack! 

 




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