1990 745 turbo/LH 2.4.
After converting to E85, cold starts are a problem. It will take two or three 5 second cranks to get the engine to light off and it needs careful throttle for 15 seconds to get a stable idle.
I suspect cold start injector because it's always been a bit temperamental cold starting, but on plain 98 octane it'd just stumble a bit before stabilising the idle on a cold start.
Now, I've checked fuel supply to injector and jumped injector to + -12v and have a good spray pattern.
With ignition on, I have +12v on one pin of the cold start injector plug. As we know, the ECU works by grounding things, this is easier for the ECU to control (just grounds through ECU chassis).
Anyway, my question is, does anyone know at what temperature the cold start injector should start operating, and how long it's run time is? I suspect no signal from ECU to cold start injector, will be testing for this tomorrow. If I find this to be the case, I may just wire the injector to a momentary on push button on dash, allowing injector priming of engine, but it's not the most elegant way and is a last resort, although it may not be a bad thing for running E85.

 

The car has to be really cold for the cold start injector to come on.

 

Thanks for that, it explains everything! I'm going to put a push button switch on the dash for sure.

 

I've heard of those cold start injectors acting up and giving hard starts in general. I'd unplug it and see if it starts better. Also, I heard on fix is to rewire the injector parallel with the starter motor so it only runs while the engine is cranking to start. I've seen one car set up that way. It started fine after sitting for months. The E85 might just be making it worse. That's my 2 cents.

 

It's all sorted out. I'm pretty sure the cold start injector on this car has never come on, never cold enough here.
I have the injector wired to a push button on the dash now, so I have electric cold priming and it works really well. When I had the cold start injector out, no signs of leakage.

 

Cool.