[07wpz]

Hi, guys!
I have this hot/warm starting problem with my x10xe engine and i want to figure it out by myself. So i'll start with the coolant temperature sensor (CTS). I'm thinking to take off the connection from that sensor and try to start the car without it when the engine is hot. What should happen, assuming that the sensor is faulty? Should the engine start normally, or it should still struggle because of the missing CTS?
Thanks!

 

[taurus]

It will struggle. The ecu defaults to a cold start mix, the cts tells it when the engine is hot so it leans the mix out. Disconnect the cts and the ecu will default to a rich mix - same symptom as a dud cts in the first place.

cts don't always give a fault code when they start to die. So either buy a replacement since they are dirt cheap and it doesn't hurt to change them regularly anyway.

Or speak nicely to someone with opcom (or buy it yourself) - you will then be able to see the cts in live data and the fuel mix settings, so you'll know what's going on.

The other option is to measure the voltage output from the cts - but I've never done that myself. Maybe someone else will advise on the details.

 

[07wpz]

Ok, taurus. Thanks for your answer!

 

[taurus]

Did a bit of digging. If you've got a multimeter you can test the CTS quite easily http://www.topbuzz.co.uk/maintenance/cts/cts.htm

The reason why I think it won't work just disconnecting it is that it is a thermistor which so far as I understand is quite a simple device that alters the resistance as temperature changes. When I've had a dud thermistor and I've tried disconnecting it all that happens is that by disconnecting it it defaults to max resistance - which is usually the coldest setting.

(PS Ignore the bit in the link about CTS being £20. You can buy them from any decent factors for less than a tenner.)

 

[07wpz]

I've replaced the sensor with a new one and there is no change in good. The engine still struggles to fire up when is warm.
Interesting, this problem seems to still be related to the temperature. When the engine is cold or near 90C it starts perfect. When is somewhere between 85C and 30C it sucks!
I'll check the engine with a tester to see what is there too.