Faulty Bosch ECU in my XM

[Stratnoid]

The Bosch engine ECU in my 1996 2.0i turbo petrol XM seems to be faulty. The Citroen part number is 96 206 231 80.
Cold starts suddenly became difficult.
The engine cranked over but would not catch without using the throttle. It drove OK after about 2 minutes.

I have replaced the crank sensor, battery, battery terminal clamps, spark plugs, ignition amplifier and knock sensor. No change.

I temporarily connected an ECU from my scrapped car. The part number is 92 304 296 80.
That car has the same XU10J2TE engine but is 2-3 years younger.
The ECU part codes are different. It started easily.

Is it safe to use the replacement ECU permanently?

Also, what is the value of the original faulty ECU? I would like to open it up and look for the fault.
I have qualifications in electronics and 'hobbyist' skills in faultfinding.

Many thanks.

[EDC5]

Whilst I can't help with your specific issue, if you plan on opening up your old ECU to have a look I'd be interested, so post up a load of pics I enjoy electronics as a hobby.... but I do enjoy tearing down things to see what makes them tick.

[ekjdm14]

Have you tried changing the coolant temp sensor yet? that would be my prime suspect in hard cold starting situations. Even if a second different ECU appeared to cure the fault, it may just have been down to different operating parameters.

Hopefully that is all it turns out to be as I've not heard much of ECU "partial" failures, in my experience they either work well or don't rather than just having an issue at a certain point like cold starts. Other makes of car (specifically Toyota 2JZGTE engine with their ECUs aged about 20-22yrs) I've seen electrolytic cap failure regularly cause issues too, but again they were rather more major, making the car undriveable.

I'd get it on a lexia first off (original ECU back in) and see what if any fault codes are logged after a short drive, and if possible check the live data parameters for things like the CTS reading, injector correction values and other things that could affect fuel/air mixture. Failing that just swap the CTS for a new one & see if that helps.