It’s Got 140,000 Miles 5.8L 351 Windsor


going to give you guys the whole run down what happened today so we rule everything as possible out!

So recently this is what has happened to me. I was driving down the road and out of no where my trucks engine just shuts off. So I think maybe no gas (can't be, just put 5 gallons in). I have power, but I do not hear my Fuel Pump primping on for 2 seconds as I turn the key. So I went and bought a new Fuel Pump. Installed it and everything was good for about 2 hours... and then it just stopped working again... (I was stuck at Goodyear) they tested the 3 wires just above going to the fuel tank (Black, Grey, Purple). Black Read .00volts, Grey Read 4.6-4.7volts, Purple Read 4.6-4.7volts. So then they used some test thingy that put volts to the Grey Wire, Read 12.(something)volts and I could hear the fuel pump turning on. So we tried cranking the engine over while they put power to the pump (with the tool they used) and still nothing! (Tried that multiple times)

So I figured to myself... The fuel pump must be good since its working but its getting not enough volts... Because it needs around 12 volts to run... But it was only getting 4.6volts. So I figured it was the wiring in the fuel pump housing... So I warrantied out the fuel pump for a new one and decided this time to replace the wires that the new fuel pump always come with... So I had to place 2 connectors (The one on top of the fuel pump housing and the one that goes to the fuel pump) I replaced the Grey (signal/power "i think") and Black (ground "i think") wires. I had to cut the Black wire because it was grounded by solder. The wire (Black) that was grounded to a fuel line on the fuel pump housing I had to cut in 2 ends because of how it was like grounded in a split. So I had to solder (My first time soldering, it was a little clumpy but still the wires where stuck on, seemed like a good connection, also gave it a good tug and the wires are nicely on there. Heat shrunk it after) So I plugged the Black wire in the A Connector terminal on the connector that goes to the fuel pump. Thats what the instructions said. And the Grey wire into the B Connector terminal on the connector that goes to the fuel pump. Made sure that the Black wire is plugged into the right terminal on the fuel pump housing connector that has the floater unit (Purple wire) on it. And the Grey wire in its correct spot on that connector also.

Finally I'm happy, that **** to me 2 hours to do. So I put the fuel pump back it and instead of just twisting and taping the 3 wires that I cut to get the fuel pump housing off (wires coming out of the top of the fuel tank). I butt connected and heat shrunk them. Just to be nice and good Also I was checking the wires and connections on the fuel pump housing and they all appear good. FUEL PUMP IS IN! Also went and bought and new Fuel Pump Relay just to waste money and be on the good consious side! Everything is ready to go!

So I go to turn the power on waiting to listen for the Fuel Pump to prime 2 seconds telling me that I did an AWESOME job and... NOTHING HAPPENED!!

So... Now... this is all I am doing right now

I left it alone for a couple hours and came back and tried multiple times to start it... I Hear Click Click from relay box under hood and a very low pop from throttle body when I twist distributor! It cranks but no start...

What in the world can that be!!

 

So,,, you can add (test only) a fused 12v test wire into the inertia switch connector to bypass (applies current directly down to the FP connector) taking FP relay etc off the diagnostic table. The PCM is in charge of the ground control for the pump=run time, but you can check and make sure there is 12v (aft of the inertia) at the pump connector to help with possible voltage drop outs, harness issues to the pump connector itself, as well as verify a timed ground there. If still no pump run, your bypass still in place,, but grounding is missing you can add in (check first for a timed grounding) a temp ground to simulate PCM control. Pump runs Y/N ?
Also,,, even though you audibly hear the pump, it's always good insurance to test for spec pressure/volume at the fuel rail schader valve.
Another thing to help with a direction to go on a No Start condition , is to have a fuel pressure tester/gauge installed on the schrader valve, as well as a spark tester installed (all visible for engine cranking) and physically verify both are present for a Start. A TFI ignition module, pick up etc if failing,,, they are always good for intermittent guess work..
The key sometimes is to prove out was 'IS' there before moving on, or to narrow the diagnostic possibility...

 

Thanks For The Reply FINALLY Someone Who Hopefully Can Help Me. I Need some help. I’ve check inertia switch it was down (not triggered) I’ve also taken known good relays and swapped with fuel pump relay (still nothing) I’ve cut the wiring harness and probed to find a hot or ground only getting about 4-6V. I’ve also got a dual tank switch so I can swap which tank is in use. I’ve checked that for voltage and it is getting like 6-8V I’ve also probed the the inertia switch EVEN THO IT WASN’T TRIGGERED!!!! I got 0.0V.

 

Sorry for 2 reply’s but I’m also wondering what would possibly happen if
I was in theory “driving”
My automatic transmission vehicle dies or stalls out
So I shift from Drive To Neutral And Start The Vehicle WITHOUT stopping or even using brakes.

 

You should/must have 12V (battery voltage with the ignition switch ON= Is the battery fully charged?) at/through the inertia connector to 'apply voltage' to the tank selector switch since its dual tanks..
REMEMBER, this is a few second 'timed' voltage application when testing,, meaning it requires a RPM tach signal for continuous voltage application=indicates engine running. With a test lead in place, it gives you plenty of time to test for applied voltages/diagnosis..

But,, using a fused 'test lead/wire' at the inertia switch to aid in voltage flow diagnosis,, it will effectively apply "constant voltage" so you can test for power distribution from the inertia (R/Y wire is th output), out to the tank selector switch, and then down at the tank connector/s. If the pump/s then run, the issue if 'upstream' of the inertia..
If by adding the test wire, you now have spec power distribution at the tank selector, and the pump connectors, Id be suspect of the grounding needed from the PCM is missing. You could add a manual ground wire to test run the 'specific' pump.

Tank selector switch voltage 'output' to tank wire colors.. R for front tank, B/W for rear tank.
'Input voltage' (closed/active powered inertia) to the tank selector connector wire color is R/Y

A stalled engine and a N restart (or attempt) would have no affect of the fuel system circuitry or PCM etc..

 

I Tried The 12V wire to inertia switch red and yellow wire and BAM my fuel pump runs!!! But it doesn’t do the 3-5 second cycle. Also what would you mean by “upstream” of inertia? Sorry it’s just I know nothing about fuel systems. Could you possibly explain what you had stated earlier
“if by adding the test wire, you now have spec power distribution at the tank selector, and the pump connectors, Id be suspect of the grounding needed from the PCM is missing. You could add a manual ground wire to test run the 'specific' pump.”

You’ve helped me do something I thought was hopeless. I will give you a donation or payment for your expertise!!

 

Progress!

By adding the test wire/12v, you've taken the PCM's 'timed' operation off the diagnostic table. PCM will remove the ground function for the "fuel pump relay" if no tach signal is produced. Without closed contacts/active fuel pump relay, there will be no flow of voltage supplied to the inertia switch.

As long as the test wire is installed, the pump will run 'continuously' if either by ignition is cycled ON, or if you tied into a voltage source that's "hot at all times", the pump will run.
Now that you verified the pump running, also takes the tank selector (at least on one tank) is operational. And, that NOW there is spec voltage down to the fuel pump connector,, otherwise, the pump/s would not run.

But, with the pump running, you still have a no start condition ??

If NO, I'd then check for spec fuel pressure/volume up at the shrader valve (top,center of engine on the fuel rail)..
With dual tanks it would be unusual for both tanks not to produce a healthy fuel supply the shrader. That said, I've seen a few gassers filled with diesel too 😝

So in closing,, with the test wire installed, the truck starts? Y/N?
Checked on both tank settings? Y/N?

 

The reason for the timed fuel pump operation is for safety foremost.
If say,, in a collision where the engine stalled with the key ON, the inertia switch didn't happen to trip and a major fuel leak was then present, fire and the risk of would be possible as unregulated fuel spilled out..
If the engine stalls, and the PCM doesn't 'see' a tach signal it removes the grounding operation to the fuel pump relay, effectively shutting off the fuel pump,, removing the hazard risk...

Timed operation secondly is to pre pressurize the fuel system after some 'sit time' bleed off for a start up. Without a timed operation available, you may have to add in some extra cranking time to produce a start up if those few seconds weren't there to build the needed fuel demand.

 

I’m still having a no start condition. Also I’ve bought a fuel hose fitting with pressure gauge. Is there a way to bench test a distributor?
Also needing to know if I pull the codes (flashing Check Engine Light) can you help me with what to do next