How to start an M20?

[whitebulat22]

As soon as I got my eta it gave me a good drive and showed me it runs well. Soon after it developed a progressively worse starting problem where the revs would not go above 0 despite new battery working and spinning the starter. It went from 99% start rate to 1% as of this week.

I had new plugs, distributor cap / ignition rotor put in, and one of the two crank position sensors replaced. These things were all done whether or not they were the problem, and it runs even smoother the times it does turn on. The first ignition rotor I got from autozone with a mismatched cap that burnt the rotor after 5 minutes of success, but the matching one I just put in hasn't fixed it. Friend said it was likely spark instead of fuel that killed it because when it goes out after starting it does so with no vibration, turning off like a computer you stop using. Fuel Pump relay has been replaced too.

The next places my bud was thinking was seeing if one of the crank sensors had gone bad or dirty, or fuel pump / filter because we can't feel pumping and the fuel pressure was already low.

I'd like to know if the two crank sensors are the same thing in two places and any additional places I may need to check to get a starting car. I need to stop getting funny looks when I tell everyone my car was a good deal (AAA dude who came to tow me looked me in the eye and said "I hope you didn't pay much for that")

[NoM54me]

There are two identical sensors on transmission but they do different things. They must be plugged in correctly or they won't work. If you can crank the engine but don't hear the fuel pump come on (have a friend close to listen), then check your fuel pump and main relays. If they are good, check your AFM. If that is good, your OBC (not ECU) may be screwy. Does it work, even intermittently? A signal from the ignition switch passes through the OBC relay, which can go bad. The OBC relay is a black box above the drivers' footwell, with two connectors. One connector is green. Two green wires go into that connector, one solid green, the other with a red stripe. Cut them, then splice them together. That bypasses the obc relay. If the OBC relay is bad, your fuel pump won't come on.

[whitebulat22]

Thanks for response- it used to work intermittently but now I've completely finished any expectation of it starting without a fix.