Engine Idle Speed - A/C Problem 1995 L Cruiser

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soberman001

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???
I have a bit of a problem on hotter Georgia days when running the A/C in my 1995 Land Cruiser. Often, but not always, the engine idle speed will increase to 1800-2200 RPM when the compressor is running. Normally, a small bump in the RPM would be normal to compensate for the drag of the compressor but this is silly.

The drag on the engine and brakes in traffic is dramatic as the engine is fighting the brakes. This is moderately dangerous in tight parking garages as you are well above normal idle speed when off the brakes (15-20 mph in first gear without a foot on the gas)

Any help on the cause and fix for this problem is greatly appreciated. I am not the most handy guy with this truck but I would like to avoid a costly dealer bill.

Thanks
;)
 
cruiserdan

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It is possible that your IAC(idle air control) may not be working properly,or maybe your throttle body could use a bit of clean-up. The IAC meters air past the throttle plate to control idle speed. The further open it is, the faster the engine idles. It may also be possible that your air intake hose between the air cleaner assembly and the throttle body is cracked. Or, your throttle cable could be hanging-up in the housing and not allowing the throttle plate to fully close.

Just some thought starters for the morning 8)
 
soberman001

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Thanks Dan.. where would you start narrowing down the options?
 
cruiserdan

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I'd start with the easier stuff first. Air intake hose and possible sticking throttle cable inspection. Then progress to a throttle body clean-up including IAC and IAC passage and lastly possible replacement of the IAC. The IAC or I forgot to say ISC (idle speed control, does the same thing) does not fail too often and they are not cheap. It is a 22270-66010 for the 93-94 1FZ and a 22270-66011 for 95-97. Both numbers are the same price, $391.11
 
semlin

semlin

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Don’t know if it’s related but I’ve noticed on the cold start up high idle issue that if the a/c is on it jumps from the usual 1700 to 1900 and takes far longer for the revs to drop down to an acceptable departure rpm (for me 1100 rpm). If I turn the AC off after waiting my usual period for warm up (about a minute) it will drop down immediately from 1900 to 1100 like it’s being held up there unnecessarily by the A/C.

On a related note, it’s been a while since anyone has discussed the high idle start up issue. Mine has edged its way up from 15-1600 to 17-1800 rpm. Does anyone know if the start up rpm is dictated by oil pressure? It occurred to me recently that this increase in revs started about when I switched to 5w30 from 10w30 and I also notice that the start up rev takes me exactly to line #3 (high safe) on my oil pressure gauge..
 
BOUNDER

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Neat!

I noticed the ever-so-slight RPM increase when I turn the AC on - nothing abnormal just always thought the AC compressor would drag on the engine - at least a bit. Now to get it to blow colder quicker - Florida is a warm state!
 
e9999

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when I start my engine cold, I don't think it goes above 1100 and to that only for a few seconds, then it drops down quickly to 700 rpm w/o A/C and to about 850 w/ A/C. I don't think the whole process takes more than 30 secs or so. (I'll check.)

and, Sem, this is with 15W40! and mine never goes over the 2/3+1 needle width level, which is when the pressure relief valve must be opening...
 
L

LCRob

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We checked the '96 we bought today and it was running at around 700 normally and right at 852 with A/C which seems about right.
 
PabloVTA

PabloVTA

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I just got a quote for that part , yeah, ouch!
443.41 and he wanted to keep it all day and charge me another 225 in labor.

What .pdf file can I get to explain this to my thick scull?

The service guy was saying it was a rotating/"idle air control valve" issue.

-uh, yeah
 
EWiz

EWiz

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Sorry to bring up an old thread.

I was having low idle issues for about the first hour of driving with my 1993 LC. Idle was around 600.

After doing some thread searching and talking to the mechanic at the dealer we believe the IAC valve was dirty.

I got some MAF Cleaner and took out the IAC valve. Cleaned it throughly. Reinstalled it.

The LC started right up and the idle speed was higher.

It was very tricky getting the screw off on the bottom. I had to find the right length Phillips bit and a 1/4 wrench to get access. I ended up grinding off some of the Phillips bit to make it the right length.

Here's some pics. Hope it helps.

IMG 5085


IMG 5086


IMG 5087


IMG 5088


IMG 5089
 
Qball

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Sorry to bring up an old thread.

I was having low idle issues for about the first hour of driving with my 1993 LC. Idle was around 600.

After doing some thread searching and talking to the mechanic at the dealer we believe the IAC valve was dirty.

I got some MAF Cleaner and took out the IAC valve. Cleaned it throughly. Reinstalled it.

The LC started right up and the idle speed was higher.

It was very tricky getting the screw off on the bottom. I had to find the right length Phillips bit and a 1/4 wrench to get access. I ended up grinding off some of the Phillips bit to make it the right length.

Here's some pics. Hope it helps.

View attachment 1478786

View attachment 1478787

View attachment 1478788

View attachment 1478789

View attachment 1478793




Awesome write up! Thank you, going to try that a bit later to see if I can get the old beast to idle a little smoother.
 

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