Newly instaled fuel pump runs continuiously, truck will not start.

 

If the pump wont shut off either the relay is stuck on or there is a problem with the circuit that controls it. As for the truck not starting there are tons of possibilities. Need more info to be of any help.

-Jon

 

Howdy and welcome farmgirl! Your in the right spot, we just need some more info.

Truck? Year? Engine? When you say "won't start", do you mean won't crank, or cranks and won't fire? Things you've replaced or checked?

Adrianspeeder

 

Unfortunately, I've only heard of 2 reasons for this to happen: 1) bad EEC ground, & 2) bad EEC. Fortunately, aftermarket reman EECs can be had for less than $100, but it's even cheaper & quicker to fix a bad ground. Check the one at the top of the L wheelwell, the one behind the L headlight, & the one above the R edge of the radiator. Then clean & tighten both battery terminals, the frame ground, & the block ground.

 

When the fuel pump remains on as long as the key is on, it won't start, and you can't get any codes, 99% of the time it means the ECM is bad. Are you able to get any codes?

 

Okay Here is more info.
Truck F 150 1987 7>0 EFI
Start of problem, pump would stop running. Discovered Interia switch had bad connection, burnt connector. Spliced together, as of now. Old pump would run continuously when key is turned on. Bought another pump , same thing, bought pressure relay switch, same result. Today sprayed 2+2 into intake, truck will start and run as long as I keep my foot on the gas pedal , so won't idle.
Pump continues to run, when I try to start it on its own. Stilll just turns over and over. So pump does not run for 2 seconds when switch is turn then cut off like it is supposed to.
Have been reading thought serious about the EEC control. Have not checkd price on that yet.
Let me know what you all think

 

sorry for typo 5.0L engine and that was a fuel pressure regulator

 

You have a bad ECU (EEC) computer.

 

where are you farm girl? i have a eec for a 88 f150 5.0 and i know it works,i am in the denver area

 

I"m in Maryland, What is the part number on yours. I got the thing out, and spent half the day trying to track the right one down. Have one on the way from Texas. Hopefully it is the right one.

 

Thanks guys, ECU finally arrived , put it in last night. Truck starts fine and fuel pump cuts off after 2 sec. like it should.
:santa:

 

Glad to hear you got it goin!

Adrianspeeder