Engine/Transmission (1998.5 - 2002) lift pump question

[concrete-steve]

I just installed a gauge to read fuel pressure and it is zero, so I am off to buy a new lift pump for my 2000. Truck has 123K on it, and I don't know how long it has been at zero, but it seems to run fine. Funny thing is, I changed the filter when I drilled the hole for the sender in the cap, bumped the starter and heard the lift pump run and the truck started fine. I would have thought it wouldn't start with zero pressure. A question, I see specs for pressure at idle, but what is WOT pressure? Also, any advise on changing the lift pump would be a help.

 

[JStrosnider]

The lift pump can be completely dead and the truck will appear to run fine (for awhile). I had that problem lift pump took a dump truck ran fine until the injection pump started to go. The WOT pressure is a touchy subject because the WOT pressure can fluctuate from 7-15 psi. The dealer will more than likely tell you as long as it's within those readings it's fine. That's what they told me. . However I don't like my fuel pressure being 7 psi at wide open throttle. I prefer 10-15 psi. A suggestion would be to add an additional lift pump or completely replace the factory lift pump with something like a FASS System (awsome system). A FASS System will run about 15 psi at idle and WOT and delivers plenty of fuel to feed the VP 44 pump. . Adding an additional lift pump eases the mind cuz it brings up your fuel pressure at WOT and also if your factory pump quits you still have a back up pump to keep from frieing the VP pump. .



What kind of fuel guage did you get mechanical or electrical sending unit? Why did you drill a hole in the fuel filter cap for the sending unit when you could have tied into the schrader valve on the side of the injection pump. That's the best place to have your guage tied into so you know what your pressure is going directly into the pump and after the filter??

 

[RAJohnson]

Welcome to the TDR. What year is your truck, can you tell us a little about it by filling out your signature. I would plug the hole you made in the FF housing and relocate to the line between the FF and VP, assuming you have a 24V. Before I would go replacing lift pump I would make sure that my new gauge was installed and working properly.

 

[concrete-steve]

I wasn't aware that I could hook into the schrader valve to get my readings, so I drilled the top of the cap... . today I am going to change this oversight. I did check the sending unit (it is electrical, not mechanical) by removing it and putting compressed air to it (15psi) and it registered fine. Thanks for the input...

 

[plongson]

Like Johnson said, WELCOME TO THE TDR!! You won't find a better place to get straight information on your truck. It is money VERY well spent.



Paul...

 

[JStrosnider]

Like Johnson said, WELCOME TO THE TDR!! You won't find a better place to get straight information on your truck. It is money VERY well spent.



Paul...

Hey guys I filled out my truck information and my profile but how do I get it to show up on my posts????

 

[plongson]

It should show up on your next new post.

 

[concrete-steve]

Ok, so this morning I set out to change my pressure gauge sending unit to hook into the schrader fitting. As Murphy's law applies itself to everything I do..... the truck is now dead. I guess cracking the lines after the filter caused it to give up completely. A small consulation, the truck is parked comfortably in my garage where it is easy to work on and I have all the tools I need close by.

 

[JHSchultz]

If you are going to change out the lift pump, I suggest you get the "vulcan relocate kit" from www.genosgarage.com and put the new pump back by the tank. Also Geno's has a fuel pressure line available that threads right on the shrader valve at the VP44 and has a 1/8" NPT female fitting on the other end for a fuel pressure gauge.

I just left mine installed under the hood... . whenever I check the engine oil and stuff I fire it up and verify I have good pressure.

 

[RAJohnson]

Steve, when you cycle the key can you hear your LP running at all, with out starting the motor. If you just bump the starter with out starting it, your LP should run for about 20 seconds. If you can hear it running bull the output side of the FF off to see if you have fuel. It could take a couple of cycles to fill the FF housing. If still no fuel and you have anyway of pressurizing the tank this will help with getting fuel to the LP and FF. Once you get it to the FF close it all up and do 2 or 3 key pumps to prime the VP and then try to start it. If you get it there and it still will not run, you may have to crack a co8couple of injector lines to help bleed the VP, then she should start.