Intermittent low idle. (1 Viewer)

Joined
Nov 3, 2004
Messages
898
Location
Frankfort, Kentucky
 
 
 
My 1994 FZJ80 has had a low idle a couple times since I have owned it.

I have owned it since the begining of winter last year. It has otherwise had the normal idle for these. Starts up around 1800 then gradually drops. Several months back it idled real low on start up cold, about 450 RPMS and was that way for a day or two. Then back to normal till just now, it started again.

Temperature is in the 30's in the AM start ups and the Land Cruiser goes right to about 450 RPMs on idle. Stays about the same whether truck is warm or cold. Started yesterday and doing it still today. Runs great otherwise.

Thanks for any guidance.

Kevin
 
Joined
Aug 8, 2009
Messages
162
Location
ma
I just had the same issue. While doing the oil seperator mod I found a cracked hose on the pcv. I also did plugs, wires, cap, and rotor, as they were original from 1994. It has been fine since. The tune up helped but I believe the pcv hose was the problem. While I was in there I cleaned the throttle body( about 1 hour job) that was nasty and really helped her gain some power! Hope this helps. Also check all vacuum lines. If you run an unlit propane torch over them( while running, and bottle turned on. No flame and the iddle changed walla your cracked hose) hope this helps.
 

landtank

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Mar 27, 2003
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19,852
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Groveland MA
 
 
 
I'd start by looking at the throttle cable. These things can hang up sometimes which initially gives a high idle until the ECU compensates for it. But then if down the road the cable fres up for some reason you get a low idle.

I've replaced a few for this type of behavior.
 
Joined
Aug 9, 2003
Messages
9,014
 
 
 
I've also had this symptom from accumulated grundge on the throttle butterfly valve area. Bend an old toothbrush to the right shape with a cigarette lighter or similar and use EFI cleaner spray to clean the back side of and the mating groove it seats in. A tuneup may help but this sticky valve is easy to get to and a very high likelihood. (don't use carb cleaner - too strong)
 
Joined
Dec 19, 2009
Messages
600
Location
Roseville, CA
Is your CEL on ?
If so, pull the codes.

Otherwise, like some have mentioned, may be a vac leak. Had the same symptons and was the case.
Also, if you havnt done anything in awhile, might be worth it to get through and do basic maintenance stuff like plugs, wires, etc .... like Doug mentioned, cleaning the throttle body is always helpful ... and check for slack in the cable.

Best of luck and let us know what you come up with.
 

80t0ylc

Hill & Gully Rider
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Joined
Sep 24, 2008
Messages
3,161
Location
Canyon City, OR
 
 
Also check the flex hose between your air cleaner canister and throttle body for cracks or leaks. They get brittle with age and the heat in the engine compartment.
Edit: Just in case you were unaware, if you pull the battery cable or the ECU fuse in the engine compartment, the ECU goes through a "learning" process that will affect your idle for several start/run cycles. I can't recall the exact # of starts before it returns to normal. Seems like 8 - 10. Don't try them all at once because the ECU needs some running time after each start. Just use it as normal so you don't wear out your starter trying to get it back to normal.
 
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Joined
Nov 3, 2004
Messages
898
Location
Frankfort, Kentucky
 
 
 
The cap, rotor, plugs and wires were all replaced not long ago.

Just a quick look I found some slack in the throttle cable. There are the two cables. One larger one from I assume the gas pedal and the smaller to a control box on the passenger inner fender. The gas pedal cable seems to be what is holding the idle where it is. The slack is in the cable going to the box on the inner right fender. I am not sure if the butterfly valve is sticking, have not gotten into it yet.

The CEL is on. It has been for the EGR code, the one that a lot of members just live with. I will check it again. I will check the PCV hose and flex hose as well as those are easy enough to do.

I looked through the FAQ trying to find anything about cleaning the throttle body and/or the butterfly valve. I did not see it, will look again.

Looking for the FAQ for pulling codes with the paper clip too.

Thanks for the help. Thought the slack in the throttle cable may shed some light. It moves freely, I can move it pretty easily with my fingers, throttling up or down. Not a lot of slack but certainly some.

KB
 
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