88 F250 died, no fuel pump activation, or injectors

[Fellro]

It fired up great, then promptly died. It is not turning the fuel pumps on, and I don't believe it is pulsing the injectors. It has good spark, and will run off gas poured into the intake. I can activate the pumps fine through the test lead. Can the module drop like that, and cause a partial failure like this? Haven't seen such before... Obviously there is something blocking it from turning the pumps on. Also, the inertia trip switch is not tripped...

 

[blacksnapon]

Remember to check the fuel pump relay (next to the pcm power relay)

 

[Fellro]

I can make the pumps run by grounding the #6 test lead. That activates the relays fine. The pumps will run, just no delivery in the motor. The computer isn't turning the pumps on.

 

[KdPate]

Pull codes and see what you find. Sounds like the computer just took a dump......

 

[Fellro]

So with good spark, the only other thing left other than potential wiring issues would be the ECM?

 

[KdPate]

So with good spark, the only other thing left other than potential wiring issues would be the ECM?

Pull your trouble codes first and see what comes up. It may be as simple as a sensor that needs replacing or it could be the ECU dumped.

 

[Fellro]

I couldn't get my scanner to read any codes... it wouldn't even power up. I had done some researching this issue, and thought I should check the grounds by the battery just to see. Well, I had to change out the battery the night it quit, in the dark, so i did not notice the wire that had broken off. Touched it to ground, pumps turned on... It fired up nicely after that.

 

[Skandocious]

Lol, betchur kickin' yourself

 

[Fellro]

With the time wasted, yup, but gotta love the easy fixes...

 

[KdPate]

It's proof that the smallest things can cause a BIG headache sometimes.....

 

[Fellro]

I know that lesson well...

 

[Fellro]

Well, my problem is back, but now seems to be limited to cold weather. It wouldn't turn the pumps on when we went below 0, then when we warmed up, it worked fine. I replaced the fuel relay and it behaved for a day, then went cold and now it won't turn the pumps on again. It does have spark, can't say if the injectors are working. Before I bypassed the relay and it ran fine, now it won't fire at all...

I have noticed the EEC relay doesn't come on, so I might try swapping it since I have spares...

 

[Fellro]

I do believe I found my problem, the EEC relay had ice int he plug. That would quite well explain the warm weather/cold weather behavior...

 

[Lost]

Glad u figured it out .