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post #1 of (permalink) Old 08-24-2000, 06:42 PM
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how do I lower my idle?

Hey I have a 87 Wrangler/YJ, with the 2.5L 4cyl fuel injected. The engine idles around 1000rpm, after about half an hour of stop and go driving the idle increases to between 1500-2000rpm. Can I adjust the idle down, or should I be looking for a sensor problem or leak?
Any help would be great.

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post #2 of (permalink) Old 08-24-2000, 06:57 PM
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Re: how do I lower my idle?

the computer controlls your idle by adjusting the iac(idle controll motor),if it idles normaly at first,i would be looking for a sensor problem,use of a "scan tool",would probably find it quickly.if you dont have one of these 3000 dollar tools,you might be better off taking it to a trusted can spend a lot more guessing and throwin parts at it.

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post #3 of (permalink) Old 08-27-2000, 10:33 AM
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Re: how do I lower my idle?

good point about the iac, but if it gradually speeds up after it's warmed up for a while, i would try spraying carb cleaner along the joint b/w the intake and the head and listen for a change in RPM.. this gasket is notorious for leaking @ somepoint in a jeeps life, and a vaccum leak like that will play hell with all your sensors and your idle.

Good luck.


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post #4 of (permalink) Old 08-27-2000, 12:37 PM
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Re: how do I lower my idle?

A vacuum leak is the likely suspect. The intake gasket is the first place to look. Tighten all the bolts at least every 15K. Also check all the vacuum hoses to the power brake booster and emission system components by pinching off the lines one at a time with a needle nose pliers, the engine speed will change.

The stepper motor that controls idle speed is a possible suspect, also. You should hear/see it kick the throttle about 3 times as you shut down the engine. Also, it should
move a little as the engine first starts. The threaded nut on the end of the stepper is adjustable, the factory idle is around 800 rpm or so.

Hope this helps, good luck!

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