[urq] temperature sender confusion

Wed May 6 18:16:08 PDT 2015

Hi Eric,

The stock urQ has indeed 3 temp sender/sensors.

The white little one at the front of the head is for the ECU. (035 919 501)

The big one (brown ?) at the back of the head is the thermo-time switch. It is for the cold start valve, the infamous 6th injector, which is electrically triggered, blue colored and at the back of the intake manifold. (043 906 163A)

The last one, small, black and near the thermo-time switch is for the blue idiot light in the instrument panel. It is a sender, but it can't be used for a gauge. Normally closed when cold (bright blue light shows a cold engine), then the light dims when the engine heats. (056 919 369P)

I guess that's your setup right now : the gauge is connected to that sender.

Now, to correct this, you'll need the proper temp sender, from the same car as your gages are from, if they are from another car. You can install it in place of the blue-light sender, or in the adjacent hole that is usually plugged. 

If your gauges are from a Coupe GT or a 4000Q, I think the correct sender is 171 919 521F, for a 120C gauge. And as you may know, the "171" in the part number tells us that it is a sender from a Golf MK1, which you should find quite easily...

Part numbers are stamped in the sender's brass body, but you usually need to clean them before...

Louis-Alain
Ex-owner of an urQ, but still lurquing.

-----Message d'origine-----
De : urq [mailto:urq-bounces at audifans.com] De la part de John Terreric
Envoyé : 6 mai 2015 15:08
À : urq at audifans.com
Objet : [urq] temperature sender confusion

Hello all,

this is my first post here, even though I have been enjoying reading you all for some time.

I have a 84 UrQ which has been well restored (engine new, suspension news, new paint) and an upgraded ECU (I suspect it was from a 4000 but I did not get any details).

Previous owners have also installed a classic 3 gauge VDO unit. 2 of the 3 gauges work (oil pressure and battery) but not the coolant temperature. Again no assurance those senders are legit.

My mechanic is confused as there are already 3 temperature senders on the engine and one is connected to the gauge but it doesn't do anything to it. It would simply not budge at any temperature. But if he puts the lead to ground the gauge goes full scale - so there is a valid wiring and gauge functionality it seems.

So does it come from a wrong sender, i.e. with the wrong resistance? Or the right sender but the wrong gauge?

Thank you for your help in advance,

Eric
84 UrQ

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