Engine/Transmission (1998.5 - 2002) Trying to solve "Lift Pump Failure Mystery"

[JL penner]

First thing you do is change your fuel filter. It doesn't matter how long ago you changed it. If your pressures are still the same then you are stuck with doing it yourself. Do plenty of research on this site to decide how you are going to fix it. The problem with going to the dealer is, they don't think you have a failure. They do a flow test, not a pressure test. And the test is done at idle. So as long as you are building any pressure at idle the dealer won't admit that there's a problem. That actually comes down from DC. The dealer can't even order a pump for you until sends the readings to DC. At least that's what my dealer told me.

 

[jmaji]

S. St. Laurent,

On your 10-21-04 post, I like what you said in this LP mess but have a couple questions. Did the Carter you put in by the tank hook up some how to the stock wire harness of the truck or is it just hot wired through the ignition? Also, you said the Carter pushed 7psi presumably in conjuction with the stock LP but you indicated you got 20 psi cruise until you replaced them both. Did that mean the stock LP was pushing 13 psi before the Carter addition? Does this extra pressure up and over the normal stock 15 psi hurt in any way the VP44? Sorry to sound stupid in this delema but I'm a new owner and reading TDR's post on all the problems with the LP has me jumping to do something quickly to keep from having to replace that VP. Until I find a resonable fix, I'm installing a mechanical FP gauge to monitor the pressure. That brings up another question. I'm lookiing at tapping my FP gauge line into the plug on the bottom of the fuel filter/water seperator like one of the members suggested. Is this an adequite place to get an accurate reading? It sure is one of the easiest places to make the connection. Thanks in advance.

 

[Steve St.Laurent]

Yes, my stock pump was making about 13 psi when I added the pusher. At the time I did it I talked with a Dodge and a Cummins engineer regarding running @ 22 psi and both said no problem other than a possible hard start condition. Since that time other information has come out but nothing really definitive. A Bosch engineer at the TDR nationals said that any more than 12 psi would be detrimental but had no explanation for why they have 15 psi stock. I've run mine for 80,000 miles with no problems and I have one of the early "bad" vp44 pumps (June build 98). I know of performance vendors that tested with up to 50 psi and didn't have a failure (although it was short term dyno testing). At this point I know of noone that has had a vp44 failure due to high pressure - not to say that there may be some out there. If you look at my original post on this - https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=19767 - you'll see how I hooked mine up. Basically I used a relay that was activated by the stock wiring harness to the lift pump and pulled the power from the PDC under the hood (so it was fused).



Easiest way I know of hooking up to the 2002's is to hook it up to the banjo bolt on the fuel filter housing - unless the 02's don't have the schraeder valve there (I don't remember). If that's the case then buy the tapped banjo bolts from Geno's and replace it.

 

[jmaji]

Steve,

Thanks for the reply. I read the thread you refered me to. On the relay, is there more than one type & if so, which one do I what? I couldn't really see what EEP furnished you in the kit. I seems like most all you needed was the pump. By the wasy, was that a 4600?

On the Gauge hook up, I believe there is a Schraeder valve on the VP inlet not on the filter housing. I read some have connected it to that inlet but I'd rather connect it at the inlet of the filter. I don't see a need in an after filter connection which would show a possible restriction in the filter. I'm more interested in what the pump is actually pushing. Thanks again

 

[darkhorse]

Taking the fuel pressure at the VP44 tells you what pressure the VP has to work with. It gives you an indication of the filter's condition. You could have good pressure from the pump but a clogged filter restricting flow & you wouldn't know.

 

[jmaji]

Darkhorse,



Thanks for the input. It would most deffinitly be easier to use that Schraeder fitting. The reason I was hesitant to put it there as some indicated a pulsing in the meter at that connection point. Maybe I'm confusing that with an electric gauge.