New VP44 Pump wont start when hot?!?!

idontcare909

idontcare909

too much time on my hands
Joined
Jun 20, 2011
Messages
59
Here are the details, its the truck in my signature. bought the truck with 117000 miles 6 or 7 years ago as far as i know original VP44. At about 238000 miles my VP finally died, I checked everything out, and had all the death code. luckily it just quit, i didn't go through all the Bull with it not starting and sometimes dying ect ect. So I Bought a reman pump from "Company X". Truck started right up, ran like a champ, So i was happy! Then i went to get groceries, come out about 45 mins later. The truck doesn't start, So i check for all the normals, fuel pressure, fuel leaks, and Check engine light. All looks good, crank the motor some more and it finally fires.

That is how it has been ever since, once its hot and sits it wont start. not once have i had any check engine lights and i scanned it anyway just to make sure and it comes up clear. This isn't the first VP pump Ive installed. but it is the first one from "Company X" i put one from Blue chip diesel on my 99 and it always starts with a nip of the key no matter the temperature. that is what i expected when i bought the pump for my 2000 from "Company X". I am not naming the company yet because I am still seeing how they handle it. So far it has been "well since there are no check engine lights, its something else, your batteries or your wiring harness isn't plugged in right, the over flow valve is bad (they sent a new one with the pump and i used it). So i have been playing the check this and that game so far.

VP pumps are notorious for having electrical issues i know. i feel as if i have a bad pump, more likely a bad computer, anyone have any other thoughts? i have an uncle who had the same problem when his pump was going bad on his 01 vp truck, no codes and when it was hot it wouldn't start. it just seems odd to me that until my original pump died i never had such a problem running the same setup that the new pump has.....

Thanks in advanced for any info or thoughts on this beast
 
What is the cranking fuel pressure?

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17-19, dude is saying that is too high. blue chip says its fine, and it worked fine on my old vp. it was a little higher because the fass i have is not adjustable, so i put in a lower spring i had.
 
Check the fuel temp at the vp and make sure the fuel level stays above a quarter. The vp wont start when the fuel gets hot and eventually burn out completely. My personal experience and has solved my problems.
 
I have almost always keep above a 1/4 tank even after i fixed the sump to keep the 1/4 tank sloshing issues down. either way a new pump should not have a hot start problem. like i said my 99 always starts right up!
 
Pull the fuel pump relay and see if it starts

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Although i have never checked fuel temp.... Guess ill have to get a new lazer temp gun
 
i have pulled the fuse from my fass, and when i have done that it seems to start, so is that saying it is too much fuel pressure?
 
Too much cranking pressure. It should kick the pump on for a few seconds and then shut it off until it starts.

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Too much cranking pressure, or too much pressure with the key on will alter the diaphragm and not want to start.
 
So now what? Get a new gas set up? Or a boos regulated fuel regulator? Why did it work forever on my old pump but not this one? And why is it only when hot?
 
You can take the power wire and wire it to a key on fuse. This will shut off the pump while your cranking. But when the key is in the on position the pump will run.
 
You would think it being a new injection pump that the diaphragm wouldn't be shot. Just doesn't make sense that the old pump never had a problem starting with the exact same set up.
 
Could be bad overflow valve on VP. They typically don't replace them on remans. I bought a new pump once that had hot start issues right from the go...it was the overflow valve.
 
The new pump did come with an over flow valve, i put it on and also changed it to another one i had in my shop to check, didn't seem to make a difference.
 
I have one customer that this happened to, still haven't figured it out. He's cool about it. It's had a computer swap, VP, lift pump, relay, and more. Cranking LP pressure doesn't affect it. This one has something to do with the ECM not giving the pump power to start.
 
I found mine does this, kicking the key on to let fuel through the vp cools it off and fires right up.

Try pouring a bottle of cold water right on top of the injection pump when its hot and see if it fires.

Some companies don't replace electronics on these remans, and this could be causing your issue.
 
diesel_importer said:
I have one customer that this happened to, still haven't figured it out. He's cool about it. It's had a computer swap, VP, lift pump, relay, and more. Cranking LP pressure doesn't affect it. This one has something to do with the ECM not giving the pump power to start.
Click to expand...

O man I feel for that guy. It's so damn frustrating. Especially when the old pump never had a problem!
 
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