Hi guys,please help, my 1.8t just wont start sometimes when hot. Last time it happened, I checked for stored codes and found engine speed sensor and coolant temp sensor fault codes. However,its not displaying any warning light on the dash. I tried starting engine with eng speed sensor disconnected (light grey connector) and surprisingly the engine fires up but with some difficulty,idling shoots to around 1000rpm and a warning light comes on,so I felt my sensor was ok but the dealer insisted that I replace with new. I replaced it but it just wouldnt start again today.
Now im thinking, could a bad temperature sensor cause the vehicle not to start when hot? My temperature runs at about 92deg celcius. For it to start today I had to pour some water around the sensor. Would a sensor fail without any indications?
The car runs perfectly well and the cooling fans kick in and out as required.

One other question,is it normal for cooling fans to fire up full blast when you first start the vehicle in the morning for about 3-5mins then they stop and then start coming on and off as required?

Kind regards,

Pombi.

 

Temp sesnsors can drift as they get old and send false information to ECM, and the ECM has no way of knowing that the sensor is lying. You can use a scanner an see what temeperature the ECM is being told and verify it makes sense.

 

I checked temp with a scanner and it reads 92deg cels, could it be a good idea to just replace the ects with a new one? I need to be certain before parting with us$60 for the sensor.

Pombi

 

It did it again today and funny enough,i unplugged the ects and it started one time and whilst disconnected, the cooling fans default to full speed though the needle on the temp gauge wil be on zero.
With this I am dead sure it is my ects that is faulty. I will replace it and update my findings.

Pombi.