Won't start when warm
 

This is a continuation of my earlier post when I said I broke down, but I thought I'd put this question into a new post.

So my problem has developed into not starting just after the engine has warmed up. If I let it cool it will start.

My code reader says no codes, but I don't trust it to be right

I know the coolant temperature sensor has been mentioned as a likely cause (although my temp. gauge reads ok).

I'm just trying to work out if there are other likely sensors or things that could be at fault?

eg. could the crank position sensor play up in this way?

Cheers

First thing I'd do is to do some more diagnosis when it's in the "no start" condition - firstly do you have a spark, and secondly do you have fuel being injected? Once you have established these two factors, there are a huge number of possible causes that can be ruled in or out, including the possibility of crank sensor. For example, if the crank sensor is faulty, you will get neither spark nor fuel, so if you are getting either or both then it's definitely NOT the CPS.

Had a similar problem on my old 850 T5. Changed the temp. sensor, fixed!
Have you changed yours? For the price of a sensor it's worth replacing IMO

I had exactly that problem on my ME7 T5, it was the intake air temp sensor (IAT 9445153) at fault. Is there anything like that sensor on an older engine?

Could be the fuel pump relay / controller

It's the coolant temp sensor. Just change the damn thing, it's a 5min job you could have have done weeks ago and fixed the problem way back then.

many thanks all, I will look deeper and try to solve this. I might have to buy a better code reader. Mine is an Autel MaxiScan which was only £13 but does not seem to work very well

https://www.ebay.co.uk/itm/Autel-Max...-/263918420480


Can anyone recommend a better one that they know works on these cars?

When the car won't start, does the temperature gauge still work. i.e. pointing horizontal when the ignition is on.

As Cookeh said...change the coolant sensor !!!
Then let us all know...

Before buying a new code reader be sure that your car is fully OBD2 compliant. If it’s a 2.5 10v then chances are it’s not OBD2! The codes can be read using a home made flash reader on non OBD cars. It’s easy to do and there are articles on here with all the details.

Jack