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SOLVED - High idle, corrects when throttle is 'blipped'

Posted: 06 Mar 2020, 11:17
by Wilso
Vehicle - 1989 2.1 WB.

My engine idles high, around 1500-2000 (no rev counter so can't be precise. it is also stable at whatever Idle speed it chooses).

I've already changed the ISCU, next steps are to clean out ISCV and look at TPS. But I believe these are fine but will check nonetheless.

Any further points to check?

Re: High idle, corrects when throttle is 'blipped'

Posted: 06 Mar 2020, 11:23
by Mocki
throttle cable ??

Re: High idle, corrects when throttle is 'blipped'

Posted: 06 Mar 2020, 20:12
by Wilso
Mocki wrote:throttle cable ??

Not too sure tbh.. haven't checked yet. However I changed the ISCU back k to the original as the one I bought seemed to make it utter when trying to maintain a cruising speed. When changed back, it carried on doing it.. .so it can't be the ISCU haha. I'll have a better look tomorrow when there's some light and good weather!! :D :D

Re: High idle, corrects when throttle is 'blipped'

Posted: 08 Mar 2020, 07:33
by Wilso
Solved!

Turns out the return spring to put the TPS back to its original position wasn't connected. When it was put back it was evident that the spring was past it, used a drum brake spring as a temp fix whilst I wait for a replacement to be delivered this week. Makes the throttle heavy a f.... hahaha

Re: High idle, corrects when throttle is 'blipped'

Posted: 09 Mar 2020, 19:25
by Mr Bean
Wilso wrote:Solved!

Turns out the return spring to put the TPS back to its original position wasn't connected. When it was put back it was evident that the spring was past it, used a drum brake spring as a temp fix whilst I wait for a replacement to be delivered this week. Makes the throttle heavy a f.... hahaha

Yes right on the nail but the slight downside is that the concentric spring round the butterfly valve spindle (if thats is what yours has got) imparts little or no side force on the spindle bearings whereas the tension spring applies considerable side force on the bearings even when the throttle stop screw contacts so more or less permanently. I did have marginal success threading a coil spring onto the exposed cable inner as it had what looks like a factory fitted screw clamp ferule on it which looked like that was what it was for. But in the event I turned up a PTFE sleeve to centralise and "lubricate" the concentric spring and rubbing parts. Design/excecution probably brilliant for about ten years but 1988 is a long way off now :roll: