Engine/Transmission (1994 - 1998) 12V Lift/Transfer pump help needed

[JoeyJ]

Need some help here



1 - I've got an issue with my lift pump leaking fuel at the gasket area- is it possible that it's just the gasket between the pump and the pre heater mounting plate? or does the pump need rebuilding? as I've never had a pump in my hands, can fuel leak there on a good pump?



2 - while removing the pump this weekend (pumps still on the truck) I snapped the fuel line from the filter to the lift pump (more stupid tax), can anybody give me the Cummins part number for this line. Had no luck between dealer and Cummins shop trying to get the correct Cummins part number as it will be cheaper than Dodge for the part.



Opinions- with 180K miles would I be better off installing a new pump, a rebuilt pump, rebuild it myself or not be concerned. I'm an ex aircraft mechanic and I'm all about preventative maintenance. If rebuild it myself is the answer does someone have the Cummins number for the rebuild kit?



Thanks to everyone in advance.

 

[Joe G.]

There should be no fuel in that area to leak. If it leaks there you should be getting fuel in your oil.



However, I have had fuel there on my truck. It was from the input fitting on the fuel filter. It's a double banjo with input from the lift pump and from the return line from the injectors. You may also have a leak from the fuel heater or the fitting on top of the fuel heater/pre-filter assembly. Normally those are air leaks and cause it to run bad or not start.



The return fuel hose may be bad and look just fine. If it leaks fuel it usually drips on the lift pump.



It seems that everything that can leak fuel drips it on the lift pump.



The lift pump has three O-rings. The one for the push button is notorious for leaking.



180K miles is nothing as far as the lift pump is concerned. Mine has 243K. The only problem has been the push button O-ring.

 

[JoeyJ]

Thanks Joe, That's what I thought but wasn't sure. I've been watching this for a while- cleaning the area and trying to determine the source. It just finally bit me as it lost prime over night on Fri and won't run for more than a few seconds after priming it. So forced maint. lol. I'm beginning to think the return line is the culprit.

I'm going to go ahead and pull the pump while I try to determine the part number for the snapped line. Figure I should go ahead and replace the O-rings, fuel fitting washers and return lines to be safe, as I've already got the block gaskets.

I've already done the heater/strainer job some time ago.



I've been wanting to add a connection for a fuel pressure gauge that's already in my pilar pod. Is there an optimum spot in this area while I'm at it? I figure I can take the banjo bolt that's most recommended and bring it into work where I can drill and tap it while I've got everything torn apart.

Thanks



Still looking for a fuel line part number, if anyone has it.

 

[Joe G.]

Throw the fuel heater away. It's worthless and will eventually cause a mysterous problem. The screw that hold the heater in the fuel heater/pre-filter assembly is just an adapter. If you take the fuel heater out the pre-filter will go right in it's place.

 

[JoeyJ]

thanks I'll do that..... any thoughts on pressure gauge fitting location?

 

[Howard Durand]

My recent experience with the same problem and the ensuing search led to the discovery that both of the rubber fuel lines were cracked and leaking onto the pump from above. It was not real easy to see from below.



I messed up the same steel line you are having trouble with. Tried to loosen it by turning the part that is threaded to the pump instead of the fitting on the end of the line. Wound up with a line that had a bad twist in it. I couldn't find a replacement at the time so removed the line and cut it in the middle. Got some new steel tubing and a brass compression coupling and made a new lower part. It is still holding so am satisfied with it.

With a new collet, I was able to use the original lower fitting with the new piece of tubing.

 

[Joe G.]

. any thoughts on pressure gauge fitting location?

#ad




The needle valve is to suppress pressure spikes that can harm the gauge or the pressure sensor depending on if you use a mechanical or electronic fuel pressure gauge. The banjo fitting is drilled from the inside because the way it is made it will guide the bit so the hole is straight. It's tapped to 1/8" NPT. Close the needle valve and then open it just enough so the gauge barely works.

 

[JoeyJ]

Thanks Howard-good idea as the replacement is about $85 from Dodge. I'll take a look and see if I have enough tubing to do it. I was thinking of using motorcycle steel braided brake line and banjo fittings as an alternative as I'm in the motorcycle biz and have them laying around. Same stuff I'll use for the pressure gauge.



Thanks for the pic Joe! Yea, I'm using Dakota digital gauges and already have the needle valve. I'm guessing that's the feed line going into the injector pump?

 

[Joe G.]

I'm guessing that's the feed line going into the injector pump?

Yep. That's where you want to know what your fuel pressure is.

 

[JoeyJ]

Thanks again Joe!!

I'm thinkin of yanking the intake to do this, any reason not to?

I really don't want to do this from the ground up.

 

[Joe G.]

Oops, didn't see this earlier today.



Take all the stuff that is in the way off or loose. Take off the air intake and intercooler pipe. The take the two nuts off the master cylinder that fasten it to the booster. Then you can lean the master cylinder toward the fender. Use a grease gun hose from the needle valve to the sensor. That way you can mount the fuel pressure censor on the fender well or firewall or something else that does not vibrate.

 

[JoeyJ]

Thanks again Joe... exactly what I was thinking. I'm going to use the steel braided motorcycle brake line I mentioned above. It's the same type they sell in the Geno's catalog for this application. I might do the same with the snapped fuel line from the filter to the pump.



It also sounds to me like the fuel return line failures to some extent are caused by heat so I'm going to consider running silver reflective heat shielding sleeves over the rubber replacement line. It's used quite a bit in racing applications, for those that aren't aware of it, and comes in various lengths and diameters. You just slide it over the lines that need heat protection.

 

[Joe G.]

The grease gun hose is pretty handy. It already has the 1/8" NPT fittings on it.



I don't know if the heat shielding will work. It appears that line that is not up to diesel specs fails. Good line does not. I have had fuel lines I bought from LarryB on my truck for a lot of miles. No problem. The lines are on the cooler side of the engine. I don't think they get very hot from engine heat. The fuel going thru the return line may be hotter than any engine heat transfer would make it.

 

[Howard Durand]

JoeyJ,

The braided line would be much easier to do. The steel line is really not very flexible and has to be pretty much an exact fit to be able to get both ends attached. The only way I was able to make mine work was to attach the upper part of the line at the banjo fitting, attach the new piece to the pump and lay it alongside the upper part. Then I could mark it where the two pieces met, cut it off and put in the coupling.

I had no choice. Where I was at the time, there was no access to replacement parts and flex line was not an option either.

 

[JoeyJ]

Joe-good info, again, lol, thanks!!



Howard, again thanks, thankfully mine happened in the driveway. I have flairing and bending tools so I may make my own line or go with the steel braided. Just can't see paying $85 for a few dollars worth of material.

 

[BigPapa]

The lift pump has three O-rings.

How about some part numbers Joe? I checked with Cummins this morning and they said no parts available for the pump, just the complete pump. My lift pump's developed a tick and I still have the one I pulled off and replaced trying to diagnose a fuel knock. I'd like to slap some new o-rings in before I swap it out again.



Thanks,

Scott

 

[Joe G.]

I don't know the part numbers. Just take one of the old ones into NAPA and get three like it from their O-ring supply. Nothing special about the O-rings.

 

[BigPapa]

General duty o-rings gonna hold up to the diesel? That's all I was worried about. If so, sounds good to me.



Thanks Joe.



Scott

 

[Howard Durand]

What is the washer that is used on the input line at the pump? Mine may be leaking a bit. Is it a specific part number or can it be replaced with an O-ring?

The truck starts harder after sitting a couple of days which leads me to believe it may be getting a bit of air in the line. Everything from the pump forward appears to be OK. No fuel leaks.

 

[DDennett]

I just replaced that washer/grommet on my truck and all it looked like to me was a small piece of either 3/8 or 5/16 (i can't remember which) fuel hose. So if you have some extra fuel hose laying around save yourself a couple bucks and a trip to cummins and try that, hind sight thats what I would have done. But I had already purchased the grommet.

Demian