1.8tdci mk2 fluctuating temp gauge

[rg1642]

Hi Folks,

Does anyone know of any wiring connections that could allow the throttle position sensor to affect the temperature gauge? It is accompanied by a 10mpg loss of efficiency. When I accelerate the gauge drops from normal to a quarter and then returns when I stop accelerating.

I have exhausted my knowledge and really don't want to go to the main stealers. I have done all the obvious,

Changed CHT sensor

Cooling system OK

Had the clock unit / dash checked

Injectors checked

HP Pump is virtually new

Changed rail pressure sensor

1 fault code for a Can Bus error to the dash

I am thinking there must be a connection between this fault code and the problem as I now know the clocks / dash itself is ok. The car runs perfectly. There is some black smoke when accelerating but I cant see the injectors being told to dump enough fuel to actually cool the head so I have put that down to the 135000 miles its done with the original turbo.

I have three cars in the family with the 1.8 tdci engine and this one has also always taken ages to warm up, even for a diesel, twice as long as the other two.

 

Any ideas would be appreciated.

Thanks

Russ

[TomsFocus]

Slow warm up time could be caused by the thermostat stuck open.  I guess it could also cause the temp to drop under hard acceleration as the waterpump will be working twice as fast at 4k than 2k rpm for example, pulling the cold rad water in quickly when its not needed.

 

[rg1642]

Yeah sorry I forgot to say Id done the thermostat as well. Did that due to the slow warm up. Also had the water pump changed when I did the cam belt. I'm stumped. Just hoping theres a software glitch or something someone knows about. Ford fitted the new high pressure pump for me a couple of years ago so that's when it had its last software update. Its always taken ages to warm up from when I first got it at 65000 but since the new pump was fitted Ive had a gradual drop in fuel efficiency as well coupled with this weird coolant gauge fluctuation.

[rg1642]

Anyone???

[rg1642]

I still got this problem and I have read others have the same but still no answers online or from Ford. 😑

Has anyone got a clue? 🤔