Temperature Issue (GTI 8v)

[alien.46.uk]

Hi All,

Quick info about the issue:

Basically temp gauge didn't work, then found the plug disconnected on the coolant temp sensor near the head. Plugged it in. Gauge works, all seems fine untill 80-100*C when the idle lowers it seems to drop in and out of 4 cylinders and will almost cut itself off.

Buggered sensor I thought ... Bought a new'un, fitted today, got some petrol ... All seemed fine again, up untill 90-100*C when exactly the same again, so now a little puzzled.

Help appreciated.

Thanks a lot.

[gtigolfthree]

Probably more to do with the engine being hot rather than an issue with the guage. Just need to find out why it wont idle when hot. Someone more experienced than me will help.   

[Wayne]

I believe the coolant temp sensor is linked to the idle / warm up circuit.

[alien.46.uk]

Forgot to say also, when its running badly (at around 90-100*), I can take the plug off the sensor and she'll immediatly run sweet as a nut again (hence the thinking the sensor was up the duffer), but obviously loose me temp gauge.

If this was mine to keep, that wouldn't bother me as I can also run off the oil temp gauge, but to sell on I'd like to get it working properly.

As to being linked to the fueling, I agree, I've had to fiddle with many a fuelling map and sensors at Uni (Motorsport Tech), but this one hasn't been touched, neither has any of the engine components, hence the confusion as to why this happens.

[alien.46.uk]

No one had this?

[rubjonny]

what year is it, or preferably whats the engine code

[alien.46.uk]

Sorry, it's a 1994, 2E engine GTI.

[rubjonny]

right disconnecting the sensor puts the car into setup mode, so that would suggest its been tuned incorrect in the past.  the setup on the 2e is the same as the MK2 digifant, so have a read of the digifant tuning guide in the MK2 section.
Only exception is you cant tune the CO with a sniffer up the tailpipe due to the cat, you need to use the CO sniffer pipe on the manifold, it has a blue cap on it

edit: also i think the idle might not be adjustible on the 2e?

[alien.46.uk]

Damnit, I thought this may be the case, not got the right kit for this at home and not legally allowed to drive this anywhere with the kit.

Based on the lack of earlier replies, I assume there's no other posabilities that could resolve this without blowing £££ on CO Meters?

As to the idle, I assume you mentioned this as I said the idle drops and tries to cut out when warm and by what I take your sentence as meaning is ... It shouldn't change as it cant be adjusted?

Many Thanks.

[alien.46.uk]

Ahh, having now read the Mk2 bit, I now realise there is a method without the tester, not what I'd like to do, but it may have to do.

And I now realise what you mean by idle ... Teaches me to read first.

This may require a little more looking into me thinks.

Good guide too, will finish reading it now.