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Old 08-09-2013, 01:27 AM   #1 (permalink)
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95 jeep wrangler 4.0 high idle at start

As the title says every time I start the beast it revs to 1500 rpms before settling to its normal 800 or so. not temp or weather dependent. I will be posting this in my jeep forum but I'm assuming it is normal. I want to know if I can bypass this function?

thanks

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Old 08-09-2013, 07:12 AM   #2 (permalink)
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Lots of cars (maybe nearly all?) do that. I think it's emissions related.

Why do you want to eliminate it? It won't consume a lot of fuel and won't be hurting the engine.

Assuming you do want to eliminate it:

It will be written into the ECU programming so to get rid of it cleanly would require access to the ECU mapping.

As a work around, do you think a switch on the idle air control valve that disables it for a few seconds after start up might work?

The idle control valve may a have a 'position learn' cycle at 'key on' so you might have to allow that to occur before disabling it.

You may get a fault code set by doing that but I think IAC operation is pretty tolerant with respect to setting fault codes.

Does that model Jeep use a stepper motor for the idle control? If so, that will have two motor windings that would have to be disabled.
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Old 08-09-2013, 11:14 PM   #3 (permalink)
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Thanks. Maybe a bit more than I can take on at this time. But isn't this the group that removes side mirrors and mount cardboard tails to squeeze out another 2 mpgs? I would have thought someone out there would want to find a way to drop 600 rpms for 4 sec times 4 a day from a straight 6 jeep.
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Old 08-14-2013, 05:36 AM   #4 (permalink)
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Probably something to do with < ~1/4 (US) Gallon per hour fuel consumption, even times 16 seconds per day, doesn't add up to much fuel.

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