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