1.8 20vt converted temp light led flashing December 19, 2021, 11:37:34 AM Hi All, Just joined and recently purchased a 1991 1.8t AUQ converted mk2 gti.Although the mechanicals seem ok, the wiring leaves a lot to be desired & is a bit of a lash up but I was aware of this, I'm slowly working my way through it. Right from cold start the car coolant temp reads hot within 5-10mins & the red overheat led starts flashing straightaway. I have checked the actual running temps and its all fine, even after a long drive so I know its a wiring / sensor issue. The previous owner stated that it must have the wrong sensor in it as its always done this but couldn't give me anymore info about it. So, my question is, has anyone else had this problem after a conversion? Which sensor do I need to be looking at? I'm assuming the sensor in the front rad is for fans & the sensor around the stat is for the ecu & gauge? Any help would be appreciated, Thanks. Last Edit: December 19, 2021, 11:41:37 AM by Super_ted
Re: 1.8 20vt converted temp light led flashing Reply #1 – December 19, 2021, 05:07:22 PM Quote from: Super_ted on December 19, 2021, 11:37:34 AMI'm assuming the sensor in the front rad is for fans & the sensor around the stat is for the ecu & gauge? Any help would be appreciated, Thanks. Yes,MK2 GTi originally would have had 2 coolant sensors (excluding rad sensor) blue 2 pin sensor for ECU and a black 2 pin for guage.Its possible the MK4 sensor for clocks works at a different rating to the MK2, this will probably be mentioned in some conversion guides. It's probably worth checking the guide anyway.
Re: 1.8 20vt converted temp light led flashing Reply #2 – December 19, 2021, 06:49:04 PM Thanks for the reply. I've done a little more digging online this afternoon & stumbled across the clubgti forums, very useful info on there. It seems if you use the mk4 sensor with the mk2 clocks it will indeed read 'high', installing a 33ohm resistor inline to the clocks will bring it back inline with what vag.com reads the actual temp is. I'll try this out and report my findings incase it helps anyone else in the future.
Re: 1.8 20vt converted temp light led flashing Reply #3 – December 20, 2021, 08:39:17 AM Hello!You're correct, I've done a couple of conversions now and can confirm the 33ohm resistor trick works a treat.
Re: 1.8 20vt converted temp light led flashing Reply #4 – December 20, 2021, 10:05:48 AM Great, Thanks for confirmation. Resistor ordered.
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