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Junior Charter Member
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Discussion Starter · #1 ·
My engine has been running great till a couple days back!!! Now it won't fire at all and the fuel pump won't stop running. I put in 5 gals of gas, same problem. New fuel pressure regulator, same problem! Put old FRP back on, still won't quit running. I am getting fuel to the fuel rail. At the present I don't know what my fuel pressure is. I'll check it tonight. Fuel pump malfunction? Any suggestions?? Stock 89 302 with stock EFI. Ray
 

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Senior Charter Member
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If it has a chip or tuning device it is likely loose at the connector.

If it doesn't have these, it is either a stuck relay, short or the EEC has gone bye-bye.

Find the fuel pump relay and test voltage from the EEC into the relay. It should activate for a few seconds and then stop when you turn the key to run but don't start.

You could try checking codes, if it won't blink anything (should get code 11 at least) this will also point to the EEC.
 

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I had run through a pretty wet stretch of road, got some water in the relay (fuel pump) and had the same issues. Fuel pump would run non-stop, even when the key was out of the ignition!

Relay is my bet.
 

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Premium Member
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Hard for it to be a short. The power coming to the relay is "always hot."

Pull the relay.
If the pump quits, it's the FP relay or the EEC power relay.

Check for 12v at the coil side of the FP relay (or at the intertia switch). It's the smaller of the two wires. If you have 12v there, I'm afraid it's the EEC power relay. The inertia switch shouldn't have 12v when the key is off.

The FP relay controls the hot side of the pump, not the ground, so if the problem is a short somewhere in the circuit, it would have to be in-between the relay and the pump, and it would have to be shorted to another "always hot" circuit, not to ground.

My bet is on the FP relay.

d



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FFCobra Craftsman
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Check the EEC plug. Mine was loose and caused the same problem.
 

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FFCobra Craftsman
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Even if the fuel pump or the EEC relay were stuck closed the engine should still start and run normally. I think you have a computer issue.
 

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Originally posted by Raybo:
My engine has been running great till a couple days back!!! Now it won't fire at all... Ray
Dang! Paul's right as usual. Maybe. I blew right past the most important info.

Let's get the info correct. When you say the pump runs all the time, you DO mean, even with the key off.

If you mean it runs when the key is on and the engine won't start, but the pump doesn't run with the key off, I'm thinking fuel pressure somehow. Maybe the pump is leaking directly back into the tank and not pressurizing the lines. Or maybe the pump motor is spinning but the pump is not, 'cause the shaft is sheared.

Please clarify what you mean by the pump is running all the time.

btw, I still think Paul's right 'cause the pump shouldn't run if the dizzy's not spinning.

d



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Discussion Starter · #9 ·
The fuel pump runs all the time when the switch is on. Key "off" and the pump is off. also, fuel pressure is right at 39 psi. Store bought Ron Francis wiring harness. Ray.
 

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When I was having EEC trouble, I unplugged the EEC connector and checked the pins to verify voltage where there should be voltage and ground where there should be ground. For instance, the fuel pump test wire should not be grounded, because that would make the pump run all the time. With the key in run, there should be 12v on the fp test wire since it's not (supposed to be) grounded w/ the EEC disconnected.
You have something wrong besides the symptom of the pump running, i.e. no start.

This should help get you started ...
If everything checks out, it may indeed be the EEC. Is there a tweecer installed? No program loaded will cause fuel pump runaway and no start.

 

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Originally posted by Raybo:
The fuel pump runs all the time when the switch is on. Key "off" and the pump is off. also, fuel pressure is right at 39 psi. Store bought Ron Francis wiring harness. Ray.
Yep,
Something's not right. I'm afraid it's the EEC.

The pump comes on momentarily when the key is turned on. That's to "freshen up" the fuel pressure in the fuel rails. The pump then should stop until the EEC gets a signal from the distributor indicating the crank is turning. That will key the computer to turn the pump back on.
The pump will indeed run continuously when the key is on, but only if the engine's spinning.

Check if you have 12v at the inertia switch when the key is on. If the coil side of the FP relay circuit was shorted to another IG-switched circuit, that could cause the problem. But I don't know how it would keep the engine from starting.

Check if you have continuity between the EEC Power Relay Black/Light Green wire and ground when the key is off. If there is, the problem is most likely the EEC. It connects the power relay to ground to turn on the fuel pump. It shouldn't perform that function when the key is off and the engine's not spinning.

d



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