I just bypassed and unhooked the Holley blue and the hard starting is no longer an issue. Had to have something to do with not enough or too much pressure on start with running pumps in line but others I have read have not had the problem? I still wonder if tweeking the spring in the Holley might make a difference but I don't want to mess with it much.

 

I ran across a sulotion to this problem... Reallly simple. What is happening is with both pumps going your getting some strong pressure at start up. But when the diaphram in the VP44 gets damaged then hard starts start to occur.

So there is so solutions for this..

1. Put a hobbs switch on the oil pressure to hold the fuel pump off till oil pressure is present.

2. Put a relay on the start solenoid leg so as you cranking the pumps are turned off. But as soon as you release the key the pump(s) start.

 

I thought it must be because of to much pressure. When you use the hobbs switch and relay will the pumps still cycle before startup? Is there any risk of starving the vp during startup? Would I just run the second pump to the hobbs switch/oil pressure instead having it tapped to the stock pump wire? Thanks for your help!

 

When I installed the Holley I did not install the regulator that came with it figuring the more pressure the better. I just now put the regulator on and hooked the Holley back up and no more hard start problem so far The regulator is suppose to supply 14 psi. At the moment I just have the low pressure light that comes on at 5 lbs and it is staying off. Juice w/attitude is on the way and I'll know more of what the pressure is running. I'm figuring it's probably ok as long as it starts ok and maintains good pressure?

 

With the plumbing configuration the problem will be when either of the pumps goes bad, it will drop pressure and force the good one to work even harder having to pull or push through the bad one's resistance and that will burn out the second one even quicker then it should go.

 

This is one of reasons to just do it right and get a proper fuel system like a AirDog 150 or FASS 150 and be done with it. Then you never have to worry about it again...

 

Yeh I know and hopefully I'll eventually be able to do that but for now I have to settle for this. When I get the edge I'll be able to monitor the fuel psi so if it drops at least I'll know. My next priority is a Fass or Air Dog.

 

Do NOT trust the electric guages - get a MECHANICAL FP guage.

 

Plumbed right the dual pump system works great, in some cases better then any single pump because you can customize fuel flow. With a switch to turn the pumps on and off independently you can control when you need the extra fuel. When I was just drivin around town doin nothin I could run just the one pump and maintain 10-12psi, when I'd hook up heavy or was gonna bein layin on the go pedal I could flip that second pump on and it would instantly go to 18-20psi. This kept me from havin to run the high pressure during daily driving.

 

If you can't affort the whole Airdog, the Raptor alone is cost effective and will not have you checking it everytime you crawl under your truck. I'm speaking from relocating stock, replacing it multiple times, going to a Holley Black, then finally my Raptor. I'm finally happy and so is the truck and the VP.