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  #1  
Old June 20th, 2017, 12:24
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poor idle with AC on

usually at lights and stopping it idles poorly with the AC running.


im unfamiliar with this issue, what is straining the idle and why?
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Old June 21st, 2017, 07:38
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Re: poor idle with AC on

when the ac is on the pcm should command the iac to increase the idle. you might have a dirty iac or intake.

is your idle speed low?
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Old June 21st, 2017, 10:52
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Re: poor idle with AC on

What are the idle speeds with and without the AC on?
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Old June 25th, 2017, 00:50
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Re: poor idle with AC on

when it occurs its starts to bog a little below 1000-700 probably, so yes low, but not consistant. IAC has been cleaned as of a few months ago while checking a different issue, jeep ran better after to. this one is just weird.

I havent had AC on much, but when its full out running and a hot day its more noticeable.
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Old June 26th, 2017, 16:38
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Re: poor idle with AC on

bump
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Old June 27th, 2017, 06:46
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Re: poor idle with AC on

does it also happen if just the fan is set to high with vent or heat?
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Old June 27th, 2017, 08:06
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Re: poor idle with AC on

Normal idle should only be around 600-700 on a Renix even without the AC. The emissions police dinged me because mine was idling at 900 hot.
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Old June 28th, 2017, 01:20
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Re: poor idle with AC on

the idle almost stumbles when its on full, and it is not consistent,kinda random. i havent tried this on heat but i will tomorrow.
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Old July 6th, 2017, 15:30
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Re: poor idle with AC on

When your a/c is on, does the compressor spin constantly, or does it cycle on and off? Your a/c system could be undercharged.
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Old July 6th, 2017, 18:46
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Re: poor idle with AC on

Would undercharged cause the idle to spudder?
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Old July 7th, 2017, 09:27
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Re: poor idle with AC on

It would cause a more constant load on the engine. If you are sputtering at idle, I would be thinking more spark plug wires, cap, or even plugs themselves.
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Old July 7th, 2017, 09:49
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Re: poor idle with AC on

Though I think it's a tuneup issue, are your vents going from vent to defrost when the idle changes? You're expected idle is higher than normal and the first thing I check in that case is for a vacuum leak and that leak may be getting worse under load. That could cause your vents to mess up.
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Old July 7th, 2017, 16:15
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Re: poor idle with AC on

I agree with these two!!! But year is it????

If it 1990 or older, Renix, the grounds may need cleaning badly!!!

Quote:
Originally Posted by old_man View Post
It would cause a more constant load on the engine. If you are sputtering at idle, I would be thinking more spark plug wires, cap, or even plugs themselves.
Quote:
Originally Posted by dan1977p View Post
Though I think it's a tuneup issue, are your vents going from vent to defrost when the idle changes?

You're expected idle is higher than normal and the first thing I check in that case is for a vacuum leak and that leak may be getting worse under load. That could cause your vents to mess up.
Could be both!!!! Or all three, vacuum leaks, needs a tune up and grounds cleaned up
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Old July 7th, 2017, 16:17
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Re: poor idle with AC on

The AC is just a distraction, unless the belts are squealing. That load just makes the wandering idle more noticable.

4.0 XJ correct idle is 750 rpm

Quote:
Originally Posted by 4x4JeePmaNthINg View Post
Would undercharged cause the idle to spudder?
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Old July 7th, 2017, 20:30
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Re: poor idle with AC on

It will dip below 750 when it's sounds like it's going to shut off. 600 or less maybe, then pick up shortly after. Once driving it's fine.
I need to replace the main grounds from the battery because of another issue. Could this hinder idle with AC on full?

Last edited by 4x4JeePmaNthINg; July 7th, 2017 at 20:34.
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