Fuel delivery problem

[93straight_six93]

How's it going guys I have a 1992 ford ranger 4.0l manual transmission. Replaced fuel pump fuel filter and relay. Cranks but no start. I have spark. I grounded the light blue/orange wire in the self-test connector, heard pump turn on and filled fuel rails with fuel which were previously dry. Then the truck started and ran but only for a little and died out again. Everytime I ground that pin the truck runs. What does this mean and where do I need to go from here? Thank you hope to hear from you soon

 

[FR-425]

Reset the inertial switch?

 

[93straight_six93]

Reset the inertial switch?

Yes I jumpered it out as well still no luck

 

[93straight_six93]

Leaning towards replacing the ecu

 

[arco777]

Check your fuel pump relay. The PCM (ECU) does not do much to control the fuel pump other than kick on the pump relay. You can check for power at the inertia switch. Usually the PCM will throw a code during cranking and KOEO self tests if it detects an issue in the fuel pump circuit such as a relay failing to kick on. The pump relay is interchangeable with other relays in the power distribution box, so try swapping it with the A/C cutout relay.

 

[93straight_six93]

Check your fuel pump relay. The PCM (ECU) does not do much to control the fuel pump other than kick on the pump relay. You can check for power at the inertia switch. Usually the PCM will throw a code during cranking and KOEO self tests if it detects an issue in the fuel pump circuit such as a relay failing to kick on. The pump relay is interchangeable with other relays in the power distribution box, so try swapping it with the A/C cutout relay.

The fuel pump relay is new

 

[93straight_six93]

Found a junkyard ecu going to try that and go from there

 

[arco777]

Sounds like the PCM is indeed not grounding the pump relay to energize it. Before replacing PCM I would be curious if the PCM is receiving the necessary signals to tell it to turn the relay on.

Just to be sure, the PCM does not prime the pump when key is turned to ON (without starting)? You should be able to hear it priming for a second or two. When you turn the key to ON, does the CHECK ENGINE light illuminate?

 

[93straight_six93]

Sounds like the PCM is indeed not grounding the pump relay to energize it. Before replacing PCM I would be curious if the PCM is receiving the necessary signals to tell it to turn the relay on.

Just to be sure, the PCM does not prime the pump when key is turned to ON (without starting)? You should be able to hear it priming for a second or two. When you turn the key to ON, does the CHECK ENGINE light illuminate?

The pump does not prime when key is turned to on. And yes the cel does light up. Only way I get pump to prime is by grounding the light blue/orange wire in the self-test connector, then the truck runs no problem til it runs out of fuel.

 

[arco777]

Weird. Try the PCM. First I've heard of a PCM's fuel pump output failing, but anything is possible.

 

[93straight_six93]

Weird. Try the PCM. First I've heard of a PCM's fuel pump output failing, but anything is possible.

I'll let you know what happens should have it this week

 

[93straight_six93]

Thanks for all of your help

 

[93straight_six93]

With the light blue/orange wire grounded in the self-test connector, the truck will run no problem as long as it's connected. The second you remove the wire I'm using as a jumper off the ground, Truck shuts off