1.6 petrol - bad cold starting; where is the coolant temp sensor & testing it?

[kevina4]

Hi, back in Feb I had a starting and flat spot issue that resolved itself. I posted in the link below and got many helpful replies. Well, my bad starting is back again.

1.6 petrol - bad starting, huge flatspot, no error codes

Hi, my '02 1.6 petrol B6, just under 100,000 miles, has become very hard to start from cold. I turn the key and it fires and then dies. Have to do this about 4 times before it starts, then it hunts around 500-1,500 RPM for a few seconds before going to a smooth idle. If I let it run for about 1...

www.audi-sport.net

The car overheated a few times so I put a bit of tape on the fan to see if it's being turned on, it seems it's not. I assume the ECU does that via readings from the coolant temp sensor, so I think I'll start there. Only problem I don't know where it is. I've not found any online resources for the 1.6, all seem to be the 1.8T and diesels. I have a Hyanes manual but that doesn't cover the 1.6. The car is '02 and it's the one with the single coil pack with HT leads and not coils over the plugs.

Also, I did find some general videos on how to test it with a multimeter back in Feb, I'll have a look again, but if anyone has any procedures I'd be grateful.

Here is a video of it starting from cold



Thanks!

 

[kevina4]

Found it after looking in the place for a 1.8T, at the back of the engine just below the combi valve. Once I removed the inlet ducting between the MAF and throttle I could find it. It's just directly below where I placed the sensor in the pic. There is also another temp sensor at the bottom right (if you're standing against the bumber, left from inside the car) corner of the rad, this just has 2 pins and I think it's just for the fan, so I juess I need that too.