Volvo Owners Club Forum - View Single Post - 1999 Auto V70 Engine Runs Like a Pile of Rocks

Luxobarge · Sep 9th, 2012, 10:29

How did you test the temperature sender?

It sounds to me as if this is faulty, constantly telling the engine it's cold, therefore making the mixture rich, which will make it run lumpy, especially at idle. The reason I say this is that the fan only comes on with the temp sender disconnected. This is wrong! The temp sender sends its signal to the ECU, which in turn tells teh fan to switch on, so it can only really be sender, wiring or ECU, in that order with sender being VERY much the favourite.

Sorry to question your diagnosis, but we need to be quite sure you have properly eliminated the sender.

When running the car, when its hot where is the needle on the temperature guage?

Sep 9th, 2012, 10:29	#9
Luxobarge Premier Member Last Online: Yesterday 22:28 Join Date: Jan 2011 Location: Horne (Nr. Horley)	How did you test the temperature sender? It sounds to me as if this is faulty, constantly telling the engine it's cold, therefore making the mixture rich, which will make it run lumpy, especially at idle. The reason I say this is that the fan only comes on with the temp sender disconnected. This is wrong! The temp sender sends its signal to the ECU, which in turn tells teh fan to switch on, so it can only really be sender, wiring or ECU, in that order with sender being VERY much the favourite. Sorry to question your diagnosis, but we need to be quite sure you have properly eliminated the sender. When running the car, when its hot where is the needle on the temperature guage? __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.