coming home today i experienced a defuel situation(i think). i was going fast on the hwy so i just figured the pump may have been hot. when i got home i felt the fuel lines, IP, fuel filter housing. wow. it was hot.( at least over 110). so, i got to thinking. if the fuel is supposed to cool the pump, that would meen it needs to circulate. but if the overflow valve dosen't open untill 14psi, then how is this possible? at idle my pump is pushing 12-13.5. and at i only can get below 10 if at wot. i know these pumps are picky, and i don't want to burn it up. any one else noticed this before?

 

Since the fuel is the coolant... You might consider using 2 cycle oil in the fuel. It will help with keeping the VP44 pump lubricated and cool. So far I'm very pleased with the results I gotten in the last year of usage...

2 Cycle oil will not affect you performance at all it might help it! I've turned 381 HP / 826 TQ with a ratio of 105:1 2 cycle oil and diesel fuel and a Edge Comp.

During the winter time I didn't use a single anti-gel product all winter. I used only 2 cycle oil at 128:1 ratio. It kept my fuel from gelling down to -20.2*F which was the coldest day in Idaho on Jan 16, 2007.

In all my testing and usage of 2 cycle oil it has protected the VP44 from damage with ULSD, gelling, and increase the performance of the truck and MPG numbers (19 to 21 MPG)

It something to think about...

 

i normaly run bio. i have used 2cycle in the past. if i run dino i use power service. i was thinking if i was to drill a small hole in the overflow valve-say .125 it would let a small amount of flow pass, and still keep my psi right? i know i can't just remove the valve, then i'd have little or no psi at all. in the end i'm just concerned that with no cirrculation the pump will over heat and die

 

Remember there is two return lines one from the VP44 and the other from the back of the head (injector return)... You can disconnect the return line back by the stock lift pump location. Then extend the line coming from the ngine. Now place it in a 1 gallon container. Start the truck... You'll be able to see how fast the fuel is returning. It not going to be much but there will be a return.

As for modifing the overflow valve. If you do the fuel pressure will fall even more. Most fuel pressure loss problems are cause by a bad LP pump or by a bad overflow valve. Lack of pressure is a bad thing...



If you want that kind of flow get a stronger lift pump... Walbro or a FASS with a Vulcan Big Line kit that would do it...

 

Here's a good example of why you need to keep the fuel tank FULL. It takes longer to warm up the full tank compared to a tank that's not so full. 35 gallons is a LOT of fuel to be heating up and while it will get warm (with the day) I can't imagine the full tank heating up as bad as a near empty tank. I re-read your post and didn't see anything mentioned about how much fuel you're running in the tank. But just like winter time up north, IF it's real HOT where you are in the summer, the same advice still holds true....keep that tank full and topped off to avoid your fuel heating up dangerously (for your fuel pump).

 

Not to hijack the thread or anything....

What if one added a fuel "cooler" to the line? maybe like an extra power steering cooler that i have laying around. I reckon that'd keep the fuel cool. Has this been done yet?

 

Maybe I missed something but I think this is a good example of the benefits of relocating the pump back by the tank on the frame rail. My pump and fuel lines back there stay cool to the touch even during a long pull.

 

the tank was alittle above half full. i agree about more fuel= more time to heat up. but, if my pump can't over power the relief valve, then the fuel just builds psi. and doesn't circulate. i guess a new pump is in store. is it possible to make the valve open at a lower psi? say,11psi. this way my pump would over power the valve and still keep me above 10

 

I wouldn't want to change the overflow valve... Think about it you got a 4 PSI window to play with. I would aim for a bigger pump if it was me... FASS or Walbro...