Don't like the adverts?  Click here to remove them

Idle problems 1KZ TE

Prado Norway

New Member
Jul 25, 2021
Country Flag
I live in Norway, and have lovely old 1998 Land Cruiser j95, with 1kz te engine and automatic transmission.
From the day i bought it (about a year ago), it sporadic jumps up and down 200 rpm on low revs, when idle and driving. It can be fine fore many days, but some times it can jump up and down all the time.
Car is without A/C, so not the compressor. I can some times here a "click" from a relay inside the dash board.

My guess is that there is some sort of sporadic electrical failure controlling the idle function on the diesel pump? But I am not an expert..

Any 1kz experts that can give me a good idea what to look after to fix this annoying idle problem?

Sorry fore my "Norwegian English"
I'd tighten the throttle cable a bit increase tickover by 100rpm , could be the ecu just compensating to prevent it cutting out ?
Engine is starting easy, and is running good, no smock or what so ever!
It switches between 700 rpm to 900 rpm at idle, so I don't think the throttle cable position is the problem.
It can switch like that from 10 times every minute to once every 10 minutes, and then be perfect for some time before starting all over again!

Off course, the car has been heavy used inside Oslo Airport Gardermoen, and has about 100 000 Hour's one the clock! Many of those hours on idle in the winter time. So could be the diesel pump is ready for an overhaul..?
Hi - welcome to the forum. 700 rpm is the correct idle speed. My UK model has an 'idle up' switch which increases the idle speed by ~300rpm. If you have that too, could that switch be faulty and somehow operating? You could try disconnecting it.
Don't like the adverts?  Click here to remove them
I had a slightly erratic idle problem (less regular than what you describe), which sometimes led to the engine almost stalling. I can't explain why, but one day I cleaned up an earth point (it was quite dirty and corroded) from the battery negative to the inner wing and that cured the problem.

I'd also agree with checking the idle up switch.

Two easy checks to start with at least.
Thanks for all replays!

Yes, I have tried to disconnect the idle up switch, but still has the fault...
I read something about a spill control valve ,and a timing control valve.. I don't know if one of them can cause the idle to be unstable?
I linked a forum post above because the SCV is becoming a common age related issue , you can tweak it a little bit as well which might help . I think how is in that link as well .

Probably something wrong withe the timing control valve/ECU/ or the wiring, is my guess after seeing the video.

The idle issue was not that problem last summer. After I took it out of winter storage a week ago it has been jumping more or less all the time.
If its been in storage all winter it could just be poor fuel which will soon be diluted by fresh fuel .
I did some trouble shouting today, and it is throwing fault codes 13 and 32. Tried to clear but keeps coming back.
Code 13 = No RPM signal after cranking and engine reaches 680 rpm+
Code 32 = Correction resistor signal.

Anyone have any good idea what can cause this fault codes?
Disconnected the resistor connection no. 1 on the diesel pump, and the car ran perfect! Put it back on, and now the car has been without any jumping at all the whole day! Cross my fingers that it was a bad connection!

Thanks for all replays!