No Signal to Injectors - ECU dead?

[drj545 3]

So I’ve been playing about getting the car running way before it’s finished, and when I plugged it all back in and hooked up everything to my surprise it had a spark. The injectors were gummed up so a tin of wd40 plumbed onto each injector and tapping the terminals across a battery got them working again. 
 

Injectors back in and I could hear them clicking when turning over, and the thing only went and fired up! However since trying to start it again, nothing!

 

Plugs are dry and no clicking of the injectors now, however I hear them click once when I stop turning the engine over (releasing the key).  Bypassed the tachymetric relay and can see 12v at the grey wire of each injector. The other violet wires go straight to the ecu. No continuity issues between the injector and pin 12 of the ecu. 

As I understand the ecu earths the injectors to create the pulse required to fire them - is there anything else I can check before I look for a replacement ecu?

[SRDT 146]

Spark, with Jetronic no spark means no injection.

You had spark when it first fired up but maybe it's gone.

[drj545 3]

54 minutes ago, SRDT said:

Spark, with Jetronic no spark means no injection.

You had spark when it first fired up but maybe it's gone.

Spark is still there - quite strong but it’s white rather than blue. 

[drj545 3]

So live update - did a bit of digging and disconnected ECU. Took a bit of wire and connected it to pin 12 in the ECU plug. With 12V going to the injectors and tapping the wire against earth I could get the injectors clicking. This meant the wire from the ECU to injectors was fine, and looking at where the wire splits 4 ways to the injectors this confirmed it. 
 

The only other thing to check was the earths to the ECU (pins 5 and 13) - resistance was 0 ohms between these pins and the car body which told me these were fine too. 
 

So this resigned me to the fact that the ECU was toast. In defeat, I sprayed the ECU plug/socket with copious amounts of contact cleaner and…the injectors have only bloody began to click again when swinging the car over!

 

So either it’s a dirty connection in the ECU plug, or there’s something intermittent going on within the ECU. I hope it’s the former - the car has been sitting for probably 20 years before I got it in Mecanno form.

 

It’s too late to start a 205 with no exhaust so tomorrow will tell if it starts and keeps going!

Edited July 15, 2023 by drj545

[Leslie green 81]

How did you get on Donald ?

[drj545 3]

Tried it this morning quickly before heading off for a couple of days. Battery was a bit flat so wasn’t swinging over nowhere near fast enough, but I could still hear the injectors clicking.  Need to jump it off another car when I get home.