No power to fuel pump

[greengoat]

Driving the other day, truck starts acting like it’s starving for fuel then dies a few miles down the road. Got it to start again, idles for a few seconds and dies. Started it up again and ran it at 2500 rpm for a minute or two, let it go back to idle and it died. First thing I did was clean the Idle Air Control. Only got worse after I put it back on, so I replaced it (IAC). Still the same. I get it home and jump the pump (high pressure) from the battery and it works fine. I didn’t check the in-tank pump yet, but I will.
Pulled the connector off the Inertia Switch, connect my test light to it, turn key on, light dies after one second.
Then I went for the Fuel Pump Relay.

Connect the light/lead to the Yellow wire -power- with key ON and OFF.
Connect to Orange/Blue (two wires) -power- with key ON only - light dies one second later (with click).
Connect to Red wire -power- key ON only.
Connect to Tan(Yellow?)/Green - Relay “clicks” when I touch it with the test light lead.

Replaced the FPR, again, no change.

Any suggestions before I start checking all the wires for bad connections/breaks?
Also, any forum links of similar problems would be appreciated!

 

[IMenriched]

Driving the other day, truck starts acting like it’s starving for fuel then dies a few miles down the road. Got it to start again, idles for a few seconds and dies. Started it up again and ran it at 2500 rpm for a minute or two, let it go back to idle and it died. First thing I did was clean the Idle Air Control. Only got worse after I put it back on, so I replaced it (IAC). Still the same. I get it home and jump the pump (high pressure) from the battery and it works fine. I didn’t check the in-tank pump yet, but I will.
Pulled the connector off the Inertia Switch, connect my test light to it, turn key on, light dies after one second.
Then I went for the Fuel Pump Relay.

Connect the light/lead to the Yellow wire -power- with key ON and OFF.
Connect to Orange/Blue (two wires) -power- with key ON only - light dies one second later (with click).
Connect to Red wire -power- key ON only.
Connect to Tan(Yellow?)/Green - Relay “clicks” when I touch it with the test light lead.

Replaced the FPR, again, no change.

Any suggestions before I start checking all the wires for bad connections/breaks?
Also, any forum links of similar problems would be appreciated!

on the right track!
look at the connections, take them apart...another here discovered, a spade completely gone inside the connection itself....or they have been known to push back inside the connections as well.

never underestimate the grounds.....make sue that they are good!
things may seem good with the test light/meter when it might be using the it to complete the circuit,(back feeding) so to speak. Or that is the theory anyway.

otherwise look for chaffed /burnt wires.

a side note, when was the last time you changed the fuel filter?

 

[kimcrwbr1]

Is your tank low on fuel maybe the in tank pump is struggleing to pull fuel up

 

[greengoat]

Going to pull the fuel filter and check the tank pump to see if it’s getting power today if it’s not raining to bad. (Wasn’t raining when this all started)

Fuel tank is nearly full.

Questions:
Does the Inertia Switch supply power to both pumps?
The high pressure pump… is this pump for priming the system only - does it shut down after a few seconds?

 

[IMenriched]

Going to pull the fuel filter and check the tank pump to see if it’s getting power today if it’s not raining to bad. (Wasn’t raining when this all started)

Fuel tank is nearly full.

Questions:
Does the Inertia Switch supply power to both pumps?
The high pressure pump… is this pump for priming the system only - does it shut down after a few seconds?

Yes....from off to on, only is on for a few seconds....as you continue to go to the start position it goes to run constant mode.

and yes the inertia switch...is part of the power supply to the FP

 

[greengoat]

Guess I should have went with the obvious.
Changed out both fuel pumps today. Tank pump was dead and the exterior pump had a short in it. Took it for a drive to warm it up good and found another problem. Got home and it started dieing??? Gonna try a new TFI, maybe that will do the trick.

Thanks for the help so far!

Edit to add: Took the new IAC off, thoroughly cleaned the old IAC and put it back on... now it runs fine??? Took the new IAC back and exchanged it. Have yet to try it out.