tune resistor

[andy400se]

Had a misfire a while ago which I traced to a dodgy connection on the 'tune' resistor.
Cleaned the connections and resoldered them
But now it doesnt matter whether the resistors are connected or not - the engine keeps running.
Have I bust the ECU or am I looking at the wrong resistors ????
Its on a 1989 400se by the way
Thanks Andy

[GreenV8s]

quote:Had a misfire a while ago which I traced to a dodgy connection on the 'tune' resistor.
Cleaned the connections and resoldered them
But now it doesnt matter whether the resistors are connected or not - the engine keeps running.
Have I bust the ECU or am I looking at the wrong resistors ????
Its on a 1989 400se by the way
Thanks Andy

Tune resistor selects between a number of different maps in the ECU, presumably 'open circuit' is an acceptable value and results in a map being selected. Maybe not the right map for the car, but *a* map and good enough to keep the engine running.

[broadside]

Andy,

Check that the resistor is the correct one for your car. My 450 was playing up and when at the dealers they found that the Tune resistor was the wrong one. The engine thought it was connected to an automatic gearbox!!! Made a diference and a new resistor was less than a fiver !!

Nige'

[wedg1e]

Less than a fiver, Jesus T. Christ. All of 3p from Maplins....

W.

[Brm Brm]

My understanding is that without the Tune resistor the ECU will default to a "safe" ie. non-tuned setting which relates to the original ECU use. So your engine probably thinks its in a Range Rover...........

[andy400se]

I try not to drive it like a Range Rover though !!
I guess the only way to be sure is to book a rolling road session and have it looked at.
Thanks