fast idle!!

hope someone can help here, my 83 DX engine has just started to idle very high (about 1600rpm) looked at vac pipes etc alls ok wound down the idle screw and its fine for a few miles then back up high as it was, any suggestions very welcome.

cheers all

very similair problem although mine is idling higher, it also varies from time to time. Tried allsorts of stuff

If i could help you mate i would but i'm here for the same thign you are

Is the O ring (seal) on the idle screw old and worn? This can leak, or allow the idle screw to come loose. A new idle screw with a new seal, doesn't cost much.

Another thing it could be is a sticky throttle cable - check the spring pulls the main throttle butterfly fully closed.

I have this problem too.  Checked all the vac pipes and aux air valve - all fine.  Throttle cable is ok too.  Cleaned out the butterfly valves also.  O-ring seal on the idle screw looks fine also.  

Problem is that 1 minute in can be idling fine at 1000rpm then next its at 1500rpm - then back down to 1000 a few minutes later.

Anyone got any ideas please??  :dontknow:

Benici said

I have this problem too.  Checked all the vac pipes and aux air valve - all fine.  Throttle cable is ok too.  Cleaned out the butterfly valves also.  O-ring seal on the idle screw looks fine also.  

Problem is that 1 minute in can be idling fine at 1000rpm then next its at 1500rpm - then back down to 1000 a few minutes later.

Anyone got any ideas please??  :dontknow:

Coarse adjustment on throttle itself.

If this was the problem wouldn't it be idling too high all the time?  Problem is I can adjust it back down to normal using the screw, but after half hour of driving its back up to 1500.

Benici said

If this was the problem wouldn't it be idling too high all the time?  Problem is I can adjust it back down to normal using the screw, but after half hour of driving its back up to 1500.

Ok well the only reason it would idle at different speeds is:

- mixture is changing
- vacuum is changing

So its possible the fuel system has issues then. That's if you've definitely checked there are no vacuum leaks, etc.

Ok thanks. I'll keep checking

I have this problem too!!!
Just had a look on vagcat but what do i need??

It shows the screw (067133432A) but no o-ring?? Anyone got the part number as my local dealer isn't brilliant.

thoyland said

I have this problem too!!!
Just had a look on vagcat but what do i need??

It shows the screw (067133432A) but no o-ring?? Anyone got the part number as my local dealer isn't brilliant.

The screw comes with the O ring. Top tip - take the pictures on VAGCAT with a pinch of salt. If the part is in brackets, it means that it doesn't look anything like that in the pic; but even if it isn't, you can't really tell, its only a guideline.

Cheers Paul,

Have ordered one this morning, so hopefully we'll be cured by end of next week. ?12 mind!!

Will update then.

How do you fit it??

I assume that it just unscrews all the way out as it does when i drive the car!!

Any tips or things to watch out for? Like springs that'll bounce out?

Just screw out the old one and screw in the new, its as simple as that.

the tight arse alternative  wrap the old one in PTFE tape :mrgreen: