Ecu n bits

[Julianw]

Other half wants a day out too, but is busy on the 20th, so 27th if that's still ok?

[citroenxm]

Yup ok 27th no problem..

[Citjon]

I'd be grateful of the idle valve if you're just going to bin it.

Possible future project for my DS21 fuel injection!

Is this to be a carburettor to injection project, or is the car already fuel injected?

If a conversion, I would pick one of the injection systems from either a 1.9Bx, or 2.0i Xm, probably the Magnetti Marelli G5, as that is distributorless.
As long as the system has a knock sensor the timing should advance the timing until the start of knock is detected then hold it just back from there.
Though if you fit a Motronic 3.1, it automatically uses the Lambda sensor feedback as mixture regulation.

Some interesting suggestions there Will, thank you. It is an efi model with original injectors and pump etc so conversion to a modern system would make sense. Original Bosch parts are not cheap, that's if you can even find them.

The cold start auxiliary air valves can seize up and I wondered about using an XM one, maybe just operated by a switch.