high idle

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  #1  
Old 08-25-06, 11:32 AM
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high idle

Isuzu Trooper 89 fuel injected. I have replaced o2 sensor, idle sensor and MAP sensor the only thing left is the EGR. Could the EGR be clogged causing the idle to stick and run high. while driving and shifting gears idle jumps up, but drops to about 2.5 rpms. really confused at some point would sputter as if suffucating for gas ?'s fuel pump. Any thoughts!
 
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  #2  
Old 08-25-06, 02:39 PM
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Originally Posted by gorilla69
I have replaced o2 sensor, idle sensor and MAP sensor
Why?
To attempt to solve the high idle or some other reason?

Originally Posted by gorilla69
the only thing left is the EGR.
Lol...oh no...there's lot's more...

Originally Posted by gorilla69
Could the EGR be clogged causing the idle to stick and run high. while driving and shifting gears idle jumps up, but drops to about 2.5 rpms.
....sputter as if suffucating for gas ?'s fuel pump.
Uh...yeah kinda...but it could be lots of other stuff

Originally Posted by gorilla69
Any thoughts!
Yes
Stop throwing parts at the problem

Lot's of things could make your idle high
First make sure the throttle stop (a screw that the linkage rests on, usually near the throttle body) isn't over tightened
Second, I'd look for a vacuum leak
A broken, cracked, or loose, hose to something as simple as your brake booster could cause the condition you describe
This would include EGR hoses
Third, check the codes
Have them pulled or if poss. DIY it
(not sure on Izzy's, there may be a procedure or it may just need a cheap reader from the parts store)
 
  #3  
Old 08-25-06, 03:50 PM
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High Idle

The Reason I changed the MAP was when I would remove the cable from the unit my idle would level off. When starting the vehicle it's fine, but as I start to drive it the idle will jump to 2.5 and stay there. when changing gears the idle jumps as far as 5.0. I will check to see if any hoses are disconnected for a possible vacuum leak. do you think maybe that would also cause a suffucation from the injectors or do you think maybe the fuel pump maybe dirty?
 
  #4  
Old 08-25-06, 04:28 PM
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Originally Posted by gorilla69
The Reason I changed the MAP was when I would remove the cable from the unit my idle would level off.
Now t h a t ' s interesting
And possibly important
Do you mean when you removed the electrical connection to the MAP sensor, the idle would drop to normal?
Or did you remove a vacuum hose to the MAP sensor?

Originally Posted by gorilla69
do you think maybe (a vacuum leak) would also cause a suffucation from the injectors or do you think maybe the fuel pump maybe dirty?
You're jumping around a bit there
There's no injector suffocation or dirty fuel pumps really
There's very few injector or fuel pump problems that cause a high idle

It's best to confirm or deny the basics first

Throttle stop
Vacuum leak
EGR
Codes
 
  #5  
Old 08-25-06, 04:56 PM
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Angry High Idle

no the connector not the vacuum hose. Ok now maybe there are 2 issues here. one being a high idle and another being the suffocating of gas. when the vehicle was starving for the gas someone would push the gas and like nothing would come out and would not idle at all. Thats when I had to park the vehicle to try and figure out what it could be. I had a lot of people state maybe the fuel pump was not working properly. After sitting I tried to start it again and it was fine which was the weird part, while test driving it again. it started to sputter and jump for lack of gas and then nothing again and then the high idle started so what the issue is. " I have no Idea now", but will definately chech for vacuum leaks and any other suggestions would be helpful. really cause I am stumped at this point. I think I really want to get the idle under control and then see what the next step is to clear the sputtering, but has not happened again (knock on wood).
 
  #6  
Old 08-25-06, 05:21 PM
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vacum leaks as slickshift pointed out is the first place to start if its the v6 model might check for a leaking throttle body base gasket by spraying around the base of the throttle body with some carb cleaner do not use much and avoid spraying near the distributer and plug wires. and it a good idea to have a fire extinguisher handy just incase.
check all vacum hoses for leaks and might even check vacum at the map sensor sometimes the vacum port can get clogged and cause a poor vacum signal to the map sensor and cause a sputtering condition.
make sure that the throttle is returning to the closed position and not binding causing a high idle.
the idle air control valve is what the computer uses to control the idle speed on the 2.8 l its screwed into the throttle body and you may want to remove it and clean the pintle valve with some carb cleaner, and about the only sensors that could affect its operation and cause a high idle condition is the throttle position sensor and the coolant temp sensor. besides the stuff mentioned above vacum leaks, throttle not closing.
 
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