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My car the CEL stays on during crank. Also stays on while running, so there is that also. I'm dealing with an intermittent no start. CEL is dim KOEO, gets bright while cranking and the car won't start. No fuel pump prime, pump runs when hot wired, (that doesn't cure the no start) sensors are all getting 5v as reqired. Has spark. Fuel pump relay is getting ground from the ECM like it should. Threw an EEC relay in it this evening, and now it runs. I'm not 100% certain that fixed it, the EEC relay in it isn't old, doesn't look bad upon opening it and inspecting. I installed the relay KOEO, and didn't hear the pump prime. walked arounf the car, got in the drivers seat and cycled the key, and got a bright CEL, fuel pump prime, and a car that lit right off. It's been an hour or so and have cycled the key 25 times, and CEL is bright and pump primes. Where are the grounds in the harness for the ECM? I'm gonna look at those and clean them up, and if it starts acting up again check voltages and voltage drop at the ECM connector.

1993 LX5.0
 

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In most fords

During crank, if the ecm is receiving the rpm signal, the CEL should be OFF

If there is no rpm signal, the CEL will stay on

you will get NO fuel pump and NO injector firing

The prime is NOT part of the crank cycle, its only 1 shot as you cycle through RUN to crank

You have to wait a few seconds with key off, to get another prime

The CEL is ground side switched by the ecm, if you have a partial short to ground after the CEL you could get a dim light, or if there is a poor ECM ground, you could get a dim light
 
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