Holley Blue hard start when warm
 

I just installed a Holley Blue pump in line with my existing pump to get more pressue to the VP44. The Blue is wired through a relay and comes on with my stock pump. It works great and starts great when it is cold but when it is warm it starts hard. Has anyone experienced this and have a solution??

Any codes come up when you cycle the key 3 times?? If you get some codes, look out for the P0237, that's one of your death codes for the VP44. If you don't get any codes, could be your sucking some air.

If the only time it is hard to start is when it's warm, :booo: you can pretty much code or no code you VP is shot craps.

If your gonna run dual LP's they have to be plumbed as shown in this thread. Any other way you do it will cause problems. Been there done that in every configuration there was before we finally got all the bugs worked out.
https://www.dieselbombers.com/5-9l-2...p-install.html

No codes, but I recently installed a new Vp44, it came with a new Alliant lift pump and a low fuel pressure light which comes on at 5 lbs. When I would get on it real hard the light would flicker a little bit (I know I need a fuel pressure gauge) anyway since the light was coming on I wanted to give it more pressure so added the Holley Blue. Now the light stays off and all is good except the hard starting. I did not bleed the system when I put the new pump but I just bleed it now, maybe that will help or I might re-configure the pumps as in the link above. Thanks.

It's not uncommon at all for these pumps to come out of the box bad. Theres just not to many things that will cause only hard warm starts and no other problems to go along with them.

check the seal around where your low pressure light sensor mounts to the VP44, mine had a similar problem, i took the sensor out, put teflon tape on it and torqued it to specs and problem was solved.

Seal around sensor is good, used teflon tape when installed, has never leaked.

Be very careful doing that. I small chunk of teflonn tape can plug a piston cooling port or damage an injector pump.

Its a much better idea to use the Teflon paste or Permatex #2.

thats what i use, the teflon paste stuff that is, im not a huge fan of teflon tape, even on plumbing for the house

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...:U:

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.

Trust Evil when he says that - you DO NOT want to use tape on these fittings - any small amount of debris will kill the IP, esp. if you are only running one inline fuel filter.

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I concur here too.

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The RACOR commercial units are also great for this purpose. They can be configured to do pretty much any flow rate and any HP rating. Single through to 4 fuel filters, big lines and everything all off the shelf.