HIGH Idle - Page 2 - CamaroZ28.Com Message Board

3rd Gen / L98 Engine Tech 1982 - 1992 Engine Related

HIGH Idle

Reply

 
Old 12-14-2015, 09:23 AM
  #16  
Registered User
 
Join Date: Dec 2015
Posts: 2
Re: HIGH Idle

Originally Posted by Injuneer View Post
"camaroken" has not returned to the site in 6 years, so not likely he will reply.

To me, it sounds like a defective coolant temp sensor. If the ECM thinks the engine is very cold, it raises the idle RPM and richens the A/F mixture.
thanks for your reply i guss i should have went into more detail about my iroc. its a 1987 5,0 tpi all stock, i have changed egr, tps, coolent temp, iac,still same high idel it will spin tire when u drop it in gear, i have engine light on, i can unplug iac and nothing changes, somtimes after i drive the car for a hour or so it does come down a littel but when i shut it off its high again, ps i also changed plenium gasket, thus car is driving me crazy im abiut to switch over to a carb setup? any help please
dual455@aol.com is offline  
Reply With Quote
Old 12-14-2015, 09:55 AM
  #17  
Super Moderator
 
Injuneer's Avatar
 
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 66,732
Re: HIGH Idle

Actually, I think you would be better off starting your own thread.... there is a lot of bad info in the posts above.

You indicated the check engine light came on. What is the code?

Have you checked the coolant temp sensor resistance vs. temperature to verify it's accuracy? Have you checked for the correct voltage on the black and yellow wires to the coolant temp sensor (sensor unplugged)?

Have you checked the resistance of the coils in the idle air controller for continuity? Contrary to what is posted above, the IAC does not set a code if it is faulty, and there is no feedback to the ECM indicating whether it is working correctly or not. Unplugging the IAC won't change anything. It is a pintle, controlled by a "stepper" motor. Pulses from the ECM open or close it in steps. If you unplug it, the pintle will not move, just stay where it was last positioned by the ECM.

This is 4th Gen/LT1 stuff, but the principles are similar:

4th Gen LT1 F-body Tech Articles

http://shbox.com/1/iac2.jpg

Finally, have you verified that the throttle stop screw is not extended out too far, holding the blades open to the point where the IAC can no longer control the idle? Have you verified that the cable or the throttle quadrant is not hanging up, leaving the blades open?
Injuneer is offline  
Reply With Quote
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ad356
LT1 Based Engine Tech
1
04-11-2015 09:49 AM
lt1matt
LT1 Based Engine Tech
17
03-21-2015 08:35 PM
1996LT1Z28
LT1 Based Engine Tech
4
03-08-2015 09:16 PM
ChrisFrez
CamaroZ28.Com Podcast
0
03-01-2015 02:33 PM
IRABuss
LT1 Based Engine Tech
445
09-07-2011 10:08 PM


Thread Tools
Search this Thread
Quick Reply: HIGH Idle


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.