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I was wondering something and was hoping someone has tried this. What happens when the speed and reference sensors are plugged in wrong (the “gray one“ into the black plug and vice versa). I mean, what would the engine do when you try to start it? Would the engine start and immediately die?

My symptom is that the engine starts reliably at the turn of the key, but dies in about a second or less. Vroom/silence. Vroom/silence. Vroom/silence. Clearly I have spark and compression, but I can’t get it running.

I jumpered the connections at the fuel relay to see if the high pressure fuel pump is running. It does seem to be quietly vibrating. I have a new fuel pump to install, but before I do that, I wanted to see if this is something anyone else recognizes as something else.

Thanks very much for your help!

Ugh. I just tried to swap the cables. No spark at all the other way. Looks like I have to replace the fuel pump, I guess. I hate replacing fuel pumps…

It sounds like you have a problem with the signal to the fuel pump relay. When you turn on the key the fuel pump should run for 3-4 seconds and then it will shut off if it does not see an ignition signal from the ECU that the engine is actually running. It might be that you are getting the <5sec "start up" run on the fuel pump and the engine will start but then the pump stops and so does the engine. Try hooking up a fuel pressure gauge and see what is going on. Another possibility is to jump the relay and see if the engine will continue to run.