Hey there from Cental California

[Greezychicken]

Hello all, my name is Don and I'm from the breadbasket of the world, the California central valley. I work for a large poultry producer and run a fleet maintenance shop maintaining class 8 trucks and trailers and agricultural equipment. I've been turning wrenches for over 35 years and love it. I have an '01 3500, quad cab, dually, 6 speed all stock. I bought it used about 4 years ago with only 200k on it. It's a little rough around the edges and I have some bugs to work out but nothing major. It gets me 23mpg and it will haul anything I need so I think I'll keep it for a while. 

 I've been reading a lot of these threads trying to figure out my fuel pressure issue. Some sound close to my problem but not exact. My problem is, almost every time I start it, the fuel pressure is different. Sometimes 7 psi, then 25, then 15,etc. It doesn't really change while driving just on start-up. It only drops 2-3psi at WOT from whatever psi it started at. I have a new vp44 with a raptor 100 transfer pump w/ecm triggered separate relay. I have also by-passed the factory fuel filter and plumbed in a spin-on fuel filter from a big truck. I have increased the fuel lines to 1/2" from raptor to filter, 3/8" from filter to VP., tank to raptor are stock. Another issue is it's hard to start when hot, but only if you shut it off and then try and restart it within 20 min or so. I'm not sure if these two problems are related or not.

I'm hoping to gain some insight in to what I apprear to be overlooking and to share some of my experiences with you all.

[notlimah]

First off welcome aboard 

 

Second I'll just list what comes to mind of your mentioned issues. 

 

Pressure difference each start.

 

Clogged filter or lines, incorrect micron rating for spin on filter, those different size lines you have, air staying trapped in your fuel pressure gauge line, fuel pressure gauge on the fritz.

 

Hard hot start.

 

Typically means VPs on the way out. How news the VP? Always had the raptor on it? Could be a correlation if your fuel pressure you've been seeing is actual and it's been starved of fuel here and there could've been enough to push it over the edge.

 

Hope that helps at least get the gears turnin! 

[JAG1]

I would get rid of the factory fuel supply lines from the tank to the Raptor by going with half inch lines. Get rid of inside the tank screens. My 01 with a 190,000 were partially clogged. Then hook up the factory filter and place the big filter on the suction side to protect the lift pump. Also scrap the fine screen on the inlet side of the Raptor. That's just plain wrong to put that in there. The prefilter should not be too small of micron. I use 30 micron pre filter. Look up Vulcan performance for upgrading parts for in the tank, he is a good person to deal with.

 

BTW it rarely happens that the tank vent could be clogged so you want check that also.

Welcome to the forum Greezychicken.

Edited July 20, 2017 by JAG1

[Greezychicken]

The vp is about 3 years old, I bought a bundle, vp&raptor, from Thoughbread Diesel. I called Air Dog with my pressure issue and they sent me a new relief valve. They didn't tell me the valves for the 100 and 150 were different but both come in the package. After putting the correct valve in, it didn't change anything so they sent me a new pump, still same. The vp only has about 20k miles of light use.

16 hours ago, notlimah said:

First off welcome aboard 

 

Second I'll just list what comes to mind of your mentioned issues. 

 

Pressure difference each start.

 

Clogged filter or lines, incorrect micron rating for spin on filter, those different size lines you have, air staying trapped in your fuel pressure gauge line, fuel pressure gauge on the fritz.

 

Hard hot start.

 

Typically means VPs on the way out. How news the VP? Always had the raptor on it? Could be a correlation if your fuel pressure you've been seeing is actual and it's been starved of fuel here and there could've been enough to push it over the edge.

 

Hope that helps at least get the gears turnin! 

 

11 hours ago, JAG1 said:

I would get rid of the factory fuel supply lines from the tank to the Raptor by going with half inch lines. Get rid of inside the tank screens. My 01 with a 190,000 were partially clogged. Then hook up the factory filter and place the big filter on the suction side to protect the lift pump. Also scrap the fine screen on the inlet side of the Raptor. That's just plain wrong to put that in there. The prefilter should not be too small of micron. I use 30 micron pre filter. Look up Vulcan performance for upgrading parts for in the tank, he is a good person to deal with.

 

BTW it rarely happens that the tank vent could be clogged so you want check that also.

Welcome to the forum Greezychicken.

I'm going to pull the tank down this weekend and have a look. I didn't notice a screen in the inlet but I'm definitely going to look again.

I was thinking about the tank vent also so I tried driving it around with the fuel cap off but it didn't change anything. I'm also going to put a clear hose between the filter and vp to see if it is air causing the problem. 

Thanks for the tips, I'll keep you posted.

 

[dripley]

Welcome to the forum Mr. Chicken. Good to see another member of the fowl family.

[JAG1]

Please report back. Interested in what you find as I have some fuel gauge fluctuation. Was very bad early on cause I caused a lot by remodeling the fuel tank, stirring up the dirt, clogged the new prefilter in a short order. I changed it and stopped most of it. The rest it Is in a fuel line connection on suction side sucking air. At least that's where I think it is... the push lock at the mayonnaise jar lid on top of the tank.

Edited July 23, 2017 by JAG1