SOLVED - No fuel pumping!

[410Fortune]

These pumps get battery power
The pcm turns on and off the fuel pump relay the relay sends battery power directly to the pump

The later trucks (06+) computers use varying voltage to regulate fuel pressure, not these trucks

Powering the pump at the relay is fine, but it does not rule out INTERMITTENT issues with the power wires between the tank and power distribution box. The fuel tank wiring connector itself is where I have seen a lot of issues over the years.. corroded pins, corroded wires, not plugged in all the way from previous repairs, etc etc. this is the last test I do before I bite the bullet and drop the tank. At this point I have already tested power at the fuse and relay, checked or bypassed inertia switch, I rule those issues out first and quickly.

As I said before I drop the tank I give the fuel pump battery power directly at the fuel tank connector, it is a very simple test. You will hear the pump run and can tell if it is healthy just by the sound (also you can check rail pressure if you have a a test port)

Then with Voltage meter you check the truck side of things look for battery power with the key turned to on (just for a second, just to prime the pump)

You have power at the pump, this means the pcm, the fuse, the relay, and the inertia switch as well as all wiring to and from is good

 

[Fix4Dirt]

These pumps get battery power
The pcm turns on and off the fuel pump relay the relay sends battery power directly to the pump

The later trucks (06+) computers use varying voltage to regulate fuel pressure, not these trucks

Powering the pump at the relay is fine, but it does not rule out INTERMITTENT issues with the power wires between the tank and power distribution box. The fuel tank wiring connector itself is where I have seen a lot of issues over the years.. corroded pins, corroded wires, not plugged in all the way from previous repairs, etc etc. this is the last test I do before I bite the bullet and drop the tank. At this point I have already tested power at the fuse and relay, checked or bypassed inertia switch, I rule those issues out first and quickly.

As I said before I drop the tank I give the fuel pump battery power directly at the fuel tank connector, it is a very simple test. You will hear the pump run and can tell if it is healthy just by the sound (also you can check rail pressure if you have a a test port)

Then with Voltage meter you check the truck side of things look for battery power with the key turned to on (just for a second, just to prime the pump)

You have power at the pump, this means the pcm, the fuse, the relay, and the inertia switch as well as all wiring to and from is good

could one jump from the relay directly to the pump, given that the relay gets sufficient power? or at that point should one just directly power the pump?

 

[410Fortune]

Yes you can jumper the relay and that will power the pump

You can test basically everything at the relay
Battery power
Chassis ground
Signal from pcm to trigger relay
And of course you can jumper relay to power pump

If the pump runs then you are usually good to go and know your issue by now
If the pump does not run

That is when my test comes into play, one final check before dropping tank
This has saved me from dropping several tanks
I have found the wiring and pins at that plug or upstream wiring at the relay connections to be the issue, not the pump

The only way I can keep from spending money on parts and labor is if I can diagnose the issue, most of the time this means ruling possible causes out

Nothing sucks worse then dropping the tank and installing new Bosch blue pump and strainer only to find out it was not needed
Been there done that

 

[DJ Al]

Applying 12v from the battery to the fuel pump power socket in relay board would do it. If nothing heard then run 12v battery jumper to the fuel pump + in connector in frame rail. Assuming ground is good the pump should run

Do yourself a great big favor..buy a 19 dollar new fuel pump relay just to give you peace of mind. I went months trying to figure
out that fuel pump won't go without a working pump relay. Yep I read your post about swapping but what have you got to lose?
Nothing else, you will have a spare,

 

[Fix4Dirt]

Do yourself a great big favor..buy a 19 dollar new fuel pump relay just to give you peace of mind. I went months trying to figure
out that fuel pump won't go without a working pump relay. Yep I read your post about swapping but what have you got to lose?
Nothing else, you will have a spare,

imo the new relays just give me problems, ive used some of the ones you get at the parts store, havent had great luck with em, but maybe thats just my luck...

 

[410Fortune]

$19 for a 5 prong 20 amp relay?!?!?

Sorry sticker shock these days it is wverywhere

 

[DJ Al]

$19 for a 5 prong 20 amp relay?!?!?

Sorry sticker shock these days it is wverywhere

Just at Oreily"s LOL

 

[Adam Robert]

SOLVED. It was not the purchase that I wanted to make, but I got the pump, tested it before installing it, and that was indeed the issue. It either went bad in the 3ish weeks I was working on it or it was dumb luck that I ever got it to fire in the first place.

Thank you to everyone who jumped on to help!

 

[Mbrooks420]

SOLVED. It was not the purchase that I wanted to make, but I got the pump, tested it before installing it, and that was indeed the issue. It either went bad in the 3ish weeks I was working on it or it was dumb luck that I ever got it to fire in the first place.

Thank you to everyone who jumped on to help!

If you used a cheap pump the second will fail shortly. These do not like the cheap pumps like airtex. I’d use nothing other than Bosch. The labor of multiple pumps isn’t worth the cost of a non-garbage pump.

 

[Fix4Dirt]

If you used a cheap pump the second will fail shortly. These do not like the cheap pumps like airtex. I’d use nothing other than Bosch. The labor of multiple pumps isn’t worth the cost of a non-garbage pump.

wasnt delphi the OE? or bosch

 

[Adam Robert]

If you used a cheap pump the second will fail shortly. These do not like the cheap pumps like airtex. I’d use nothing other than Bosch. The labor of multiple pumps isn’t worth the cost of a non-garbage pump.

I got a Precision Fuel Pumps brand from O’Reilly. I’m not familiar with the brand, but for $200 it better be good.

That was the last major thing I had on this one, so put that in, cleaned it up, put it for sale and it sold in 25 hours.

 

[Fix4Dirt]

I got a Precision Fuel Pumps brand from O’Reilly. I’m not familiar with the brand, but for $200 it better be good.

That was the last major thing I had on this one, so put that in, cleaned it up, put it for sale and it sold in 25 hours.

congrats! usually the store brand pumps are $$$, way marked up, and imo not as good as some others... usually they are rebranded meh ones, as opposed to something like bosch or delphi... ive never seen a 200 FP before, pretty sure 130 was the highest on rockauto from delphi or something

 

[410Fortune]

Precision is not the best not the worst but still
We only recommend Bosch blue replacement pumps on this forum because dropping the tank sucks

(Or you can use walbro
Performance upgrade)


Good luck glad you found the issue!