mattn124

Hello everybody! Sorry to put another VP44 thread on here, but I really could use some help before I plunk down $1000 or so for a new pump.

My truck is a 1999 2500, 4x4, 5speed manual, CTD with 276,XXX miles. I bought the truck used with 180,000 and I have not replaced the injection pump yet.

Here is my problem: hard to start when hot. What I mean is that when i first start the truck in the morning it will turn over very briefly before firing right up. But, if after driving awhile and the engine is fully warmed up, if I shut it off and try to restart a few minutes later it is hard to start. The engine spins over freely, but it spins and spins before it finally starts. Sometimes it is this way for hours after I shut it off.

I have read that this is a sign of the VP44 failing. Here are more details:

I have a mechanical fuel pressure gauge tapped to the top of the filter canister. After re-doing my lift pump setup 4 years ago (Airtex factory-replacement offering from O'Rielly's with the Vulcan Big-Line relocation kit) pressure has always been great! I have a small filter from Napa in front of the lift pump, it's more of a metal mesh screen inside than filter) and just use the factory replacement filters in the factory canister.

Pressure from this setup is 17-19 psi at idle, dips to slightly above 10 psi at WOT. Moving the pump to the frame and larger lines on it have helped a lot.

I have read that too much pressure while cranking can cause this condition; when cranking the engine i read 15 psi on the gauge, is this too much for hot startup?

I have also read about using tool #3163834 or making your own by jumping some wires to test the VP44, will that work in my case? My truck starts fine when cold and always (so far) eventually starts when hot. Does this test help trouble shoot a failing pump or is this only good for trucks that will not start at all?

There are no codes being thrown by this, I check it with a reader cant do the key on-off-on thing on my truck

Also, another detail I can tell you is that when you turn the key and the lift pump kicks on to prime everything up, once the lift pump quits running the pressure drops immediately back to zero. I believe that this is what is supposed to happen.

About 4 months ago I thought my VP44 had failed, truck would only start sometimes and was throwing codes about the IP, but I lucked out and it was just a bad relay. I replaced both the fuel pump and horn relays and it was working fine until about 2 weeks ago this hot start issue came up. Although, I just recently started to drive the truck more now that I need to pull my trailer with mowers around cutting grass so it might have been doing this back then and I just never experienced it.

Is there any way to tell if my VP44 is original or has been replaced before?

I really appreciate any help! I think I may have to spend the $$ for a VP44, but I just want to check everything out first.

I know I wrote a lot,, thank you for any help!!

SIXSLUG

go to bluechipdiesels website and read the diagnosis section. It is really informative.

dsldan

when engine is hot, prior to starting try disconnecting the fuel pump power and see if it starts, if it does it indicates a bad VP44

DodgeRam24V

2 things, the codes will not appear the key on/off in a 99, mine dont?

how did you get codes and what are they?

mine started hard when it was sucking air at the tank module connection, found out by putting the drain hose from the fuel canister in a clear bottle and running the lift pump (engine off, drain valve opened, powered up the lift pump from the battery) it was pumping air and fuel, the fuel pressure was as good as always.

if i remember correct, it started hard all the time though.

i had already put a longer drain hose on my filter canister, came in handy.

mini14

check for codes, if u dont find any, when motor is warmed up pour some cool water over the vp44, if it starts after that then u know the pump is ng.

mattn124

Thanks for all the responses!

Thanks for the tip DodgeRam24V, I will look into if my LP is pumping air with the fuel. Also, as I said, I use a scanner plugged into the OBD-II port to check for codes. I have no codes in my truck. I think you are right, none of the 1999 trucks did the code display with the key on-off-on trick

Sixslug, that bluechip site has a ton of great info, thanks!

Dan, when you say to disconnect fuel pump power, which pump do you mean, the injection pump or lift pump or both?

mini14, I am thinking of trying this also. Do you think that cooling it off with compressed air would work too? something about hosing down a component that has a computer on it worrys me.

Thanks again for all replies!

rebal

Lift pump if your diaphragm in the vp44 is bad this is a common sign of a hot start issue by unpluging the lp it relieves the internal pressure and it should start . normally caused by low fuel pressure at some point

mattn124

ok, thanks!

When I get the chance I will replicate the hot-start issue and try starting it with the lift pump disconnected. If it starts better with it disconnected then that's a pretty sure sign on VP44 failure?

I will also try the method of cooling the injection pump down and seeing if it starts better.

At least the truck is not my daily driver to work and back everyday. I will probably have to wait until the weekend to do these tests.

Thanks everyone! I will post my results.

DodgeRam24V

this is why i have 2 Dodges

mattn124

well, today I replicated the hot start event. It was turning over and over and finally started. So I shut it off, then unplugged the wire that gives power to the lift pump and it started right up!

Guess that means I need a new VP44.

What about the idea of installing a relay on the lift pump so it does not run while the starter is engaged? Would that extend the life of the pump I have? Or is that just a way for me to find myself stranded?

How long can a VP44 live like this (without relay)? I just dont have the time to fix it right now and I can limit the truck to just driving it once a week or less for the next month or so.

mrclean

That'll work......
There was a similar problem with FASS installations on some 2nd Gen 24V trucks. Many folks wired the relay into the power window circuit, but you could probably use any circuit that's not hot when the key is in the "start" position.
No way to tell how much longer the injection pump will last, so I'd advise putting aside some cash towards a new pump........

DodgeRam24V

I'd have to back up and read all of this, i didn't.

if your want your fass to run after it is started, i had a Barry Grant fuel pressure switch via a relay to power up my pusher pump when i ran 2 pumps. 1 being the stock lift pump.

i had it on the oil filter head so when it got oil pressure it connected the circuit and turned on the pump via the Barry Grant relay.

it worked quite well. i do not run 2 pumps anymore, too much trouble, FASS harness, triggered by the stock lift pump wire from the ECM.

Dane

That's exactly how my truck acted right before the vp44 died for good. No codes were set

mattn124

Dodgeram24V, thanks for the tip but I do not have a Fass lift pump. I am running an Airtex pump moved to the framerail with the relocation/big line kit from Vulcan performance. Pressure is monitored by an Isspro mech guage. This setup has been used for 4 years and still gives me 17-19 psi at idle and no less than 10 psi at WOT.

Dane, how long did your truck do this before the VP44 quit entirely? Were you always able to get your truck started, right up until the end? Was the truck still running good?

Signs are showing that I will be spending my tax refund on a new VP44, are there any other services I should do to the truck when I do the VP44? I think the crankshaft position sensor is easy to get to with the injection pump out, good time to change that.

Any other seals/gaskets/etc... that are easier to do while the injection pump is out?

What about the dowel pin repair in the timing cover? I have been contemplating that service... I might search and/or post another thread about that though

dsldan

That would be the cam sensor, the crank is the one closer to the starter