Idle running high

KITT · Post by **KITT** » Sun Aug 07, 2005 9:26 am

Hi all,

My S-reg 16v has started having a problem at idle

. It won't idle below 1000prm and sometimes sits anywhere inbetween 1000 and 1300rpm! It used to idle at ~850rpm but won't any more. It's almost like the throttle's stuck open slightly. Any ideas folks?

cheers

Matt

david burton · Post by **david burton** » Mon Aug 08, 2005 12:34 pm

this is a common problem, mine used to do it but eventually it goes away

if you load the engine at idle (put headlights and blowers on / put it in gear and let the clutch out slightly) to bring the revs down a bit - do the revs then stay at 900ish? that's what mine used to do.

Have you changed any of the air filter kit? I wonder if mine did it because I removed the warm air (for cold start) pipe....

I cleaned the air filter up and throttle body, and it doesn't happen any more. I never got to the bottom of it though, so if you find out - let me know!

KITT · Post by **KITT** » Mon Aug 08, 2005 1:00 pm

Thanks for the suggestions Dave, I'll try loading everything up on my way home later and report back.

The car is totally standard, as I have a kit car for modifying

I opened the air box for a look see yesterday and the air filter did look fairly dirty so might change it to see if it helps. How do you clean the throttle body? It looked pretty clean when I peered down it with the butterfly open and didn't feel like it was sticking in any way.

Really looking for a cheap (free!) solution as I'm short on funds at the moment

david burton · Post by **david burton** » Mon Aug 08, 2005 2:08 pm

tey an ecu reset, then get carb cleaner (4 quid from halfords) and spray it down the butterfly, get a (lint free) rag to wipe off any residue and muck.

just keep persevering - my problem went away after a few resets (doesn't make any sense tho)

KITT · Post by **KITT** » Mon Aug 08, 2005 2:31 pm

I assume to reset the ECU, you disconnect the battery for a few minutes? I really don't want to do this as last time the battery was disconnected the alarm went t**s up and I needed a new one (Â£Â£Â£)! They said it shouldn't happen again, but I'm a little wary now

KITT · Post by **KITT** » Mon Aug 08, 2005 6:40 pm

Just confirm, loading the engine when stopped (i.e. lights on, heater on, windows down and held), does slow the engine back down and make it idle normally there after. That is until you blip the throttle, after which it stays high

robin · Post by **robin** » Wed Aug 10, 2005 12:01 am

change the temp sender

this has been a major and common problem for the mk4 polos

i have changed mine a few times and everytime it has cured the hunting of the rev's at idle

KITT · Post by **KITT** » Wed Aug 10, 2005 10:50 am

robin wrote:change the temp sender

this has been a major and common problem for the mk4 polos

i have changed mine a few times and everytime it has cured the hunting of the rev's at idle

But the temp guage works fine

Or is there a different one that feeds the ECU info and if so where is it?

david burton · Post by **david burton** » Wed Aug 10, 2005 3:22 pm

there is a different one on the RHS of the engine just under the distributor

I changed mine but it didn't help my high idling . mine wasn't hunting though, it just stayed at 1200rpm.

could help, it's only 20 quid or something. there's a big post about it here somewhere.

KITT · Post by **KITT** » Wed Aug 10, 2005 8:44 pm

Strangely, it seemed ok today

I'll keep an eye on things and try the suggestions if it comes back.