QuestionHello Stephen - a few weeks ago you advised me on my cold-start problem on my 1984 Alfa Spider. I'm still troubleshooting. I put in a new MSD coil per your tips, model 8202. (That's compatible with stock, right?) It works but it may not have cured my cold-start problem, so I think it may not be an ignition system problem as you had suspected. I didn't put in NGK plugs yet per your recommendation, but the car used to start cold with any old plug - at some point, something broke, so plugs aren't a likely cure in my opinion. I don't think I SHOULD need an aftermarket ignition box either. Here's an update and some new questions:
(1) I've pulled the connector on the cold-start injector and never measured any voltage across the connector terminals, under any conditions (cold cranking, etc...). With connector on, it doesn't spray any fuel either, far as I can tell (using a paper towel). This must indicate it's never being activated by the thermo-time switch? I connected 12V to the CS injector and observed it opening and closing with a click, so I think it would work ok if it were receiving a signal. So now I'm suspecting a bad thermo switch AND/or a wiring issue, as it appears to me from the wiring diagram the CS injector should always have 12V and the thermo switch simply would provide a ground. The car starts the same with the CS injector connected or not. Can you recommend any other tests/troubleshooting tips? I am an electrical engineer and can probably fix this problem myself eventually. Changing out some sensors would be pretty easy.
(2) My submerged fuel pump. How should I verify it's working? In my testing, I've measured voltage at both the motor wire and the fuel gauge sender wire, but the car runs the same whether the motor wiring is connected or not. The main fuel pump is new.
(3) The car is will start and seems to run ok right now (even though I've kind of got it taken apart). I observe little blackened droplets coming out of the tailpipe when idling, that stain my driveway. No smoke. Could this be unburned fuel,due to an extremely overrich mixture, or more likely condensation?
I'm bringing the car into a shop tomorrow that claims to know Alfas, to troubleshoot oil leak and starting/driveablility. Should I point them in any particular direction?
Thanks for your expertise as always.
Answeritem 1- the cold start injector gets positive from the starter solenoid and neg from the thermo switch. It is only activated when the starter is energized. And when it should be used is controlled by the thermo time switch. The resister in the switch is prone to failure. So, yes, you are on the right track there.
item 2- Disconnect the wiring at the main pump, undo the hose at the intake of the main pump and put it in a bottle and activate the pump system by moving the flap on the airflow meter (with the ignition on).
item 3- it is condensation and unburned fuel and maybe valve stem seals starting to go.
If the shop knows alfas they will not need any help
If you have a mixture problem at speed the airflow meter could have worn printed circuit where the lever passes over it (it moves with the flap to send a resistence signel to the ecm).
