Hi,

Have a slight issue with the idle on my classic uk turbo, when slowing down at traffic lights etc the idle drops to 500-600rpm then rises again to normal 800rpm. It doesnt cut out and the revs dont go above 1000rpm.

Today i have fitted a new MAF, checked hoses, cleaned the ICV (which was filthy) fitted new panel filter and done an ECU reset but the issue is still there?

Is there anything else worth checking? Any way to check the ICV is working properly?

The engine is standard other than panel filter and prodrive intercooler hose kit.

 

I found my plugs were a little loose when this was happening on mine - took the plugs out to check them and they were only finger tight. I know they'd been fitted properly as I did them myself so I have to assume that they need checking more often

 

Yes checked them, only replaced them last month as part of its full service. Leads are all in good condition.
Runs fin when driving it just this idle is annoying me

 

Dose it do it all the time or just when cold or warmed up ... The reason I ask is my scoob dose the same when it's only been running a few minuets once warmed up its fine ? Was told to change the coolant temp sensor which I will be doing soon ...

 

When cold it idles at 1500rpm and slowly drops to normal 800rpm.

When its warm I notice it, usually as im slowing to a standstill, the revs dip and then recover and it dips again slightly but doesnt stall.
Sometimes it they also hang at about 1000rpm before dropping to 800rpm again when warm and at standstill.

 

Have you got a VTA dump valve? my last car did this especially after remap and turned out to be the bov, changed to recirc and solved the issue.

 

No, standard recirc valve fitted. Don't know what else to check now, might have to buy a ICV and try that?

 

Possibly the lambda sensor or the icv is on its way, try replacing lambda first as its cheaper

 

Yes think i might change that, car has done 92k on original so probably a good call.

Can you recommend anywhere to get one from? I guess dealers will cost a fair bit.

 

Import car parts or dealership for decent one, cheap ones can be hit or miss tbh and may end up costing more if it fails within a short period of time.

 

No idea if your car has one - but the idle control valve

 

Yes, ICV, I have cleaned that, it was filthy but hasnt made much difference

 

may still be faulty - thats where im putting my money