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

[Joe G.]

Howard,



Have you taken out your fuel heater? If not, it's a good idea to do that. It's worthless regardless of where you live anyway.

 

[JoeyJ]

As Joe said, the o-rings seem to be nothing special. I bought a good assortment of O-rings in a plastic container with compartments at NAPA a while back, that has come in handy several times.

Well, I'm diving back into it tonight to start yanking everything. I'll let you know how it goes and try to take some pics as I go.

 

[Howard Durand]

Joe,



I left the pre-heater out when I replaced the pump.

The washer at the input to the pump looked like it was made out of some sort of fiber material. It looked alright and I didn't really have a choice, I had to use it.

I don't seem to have a fuel leak so am suspicious of this washer since the truck starts like there is a bit of air in the system after sitting for a couple of days.

If it has only sat overnight, it starts on the first turn but if I try to move it too soon, it will sputter or die. Let it idle for a while and then it runs OK. I may need to adjust the idle up a bit too. It is getting colder here at night and, since someone messed up my garage, I have had to let it set outside a lot.



To comment on what Big Papa said about "O" rings, I have wondered about them a few times too but I think most of them can handle almost anything now.

 

[NFrost]

Joe, I can run #2 with 10% biodiesel with P. S. down to zero with the heater functioning. Don't know how much lower I could go because last winter was unusually mild. If it's not working I can't use it below 20 degrees. I don't think it is worthless.

 

[Joe G.]

Howard,



Some guy a couple of years ago had an air leak that he could not find. I suggested the bucket of water test. He did that. It was that fiber washer. I have no idea where to get a replacement. You can always install a barbed fitting there and use a longer fuel supply hose. So far, my fiber washer has been behaving itself.

 

[JoeyJ]

Ok so I finally got off my butt to fix the truck last night after work. BTW I ended up sourcing the hard fuel line from Cummins for less than half what Dodge wanted for it. I'll post the part number later. Everything went fine. I pulled the master cyl only and was able to access the return fuel line the pump and by using long wire ties, I was able to pull all the wiring harnesses up against the intake and out of the way. I removed the 2 relays on the fire wall and left the connections intact. I then used a long wire tie to secure it over around the clutch resevior. that allowed me to get access to the banjo fitting for the broken hard line to the lift pump.

OK got everything together replaced o rings in primer pump and inlet valve, new return hose using crimp clamps, new fuel filter (filled) and before bolting the master cylinder cranked it to check for leaks. Crap... batteries low... break out the charger.

ok now crank it... . got her going..... still leaking. Seems to be coming from the pump body itself but could be the the water sensor as it seemed to be pretty wet and could be dripping onto the pump. But... ..... while checking for the leak at an idle the truck dies. Seems it ran until the fuel in the filter was used up. So now I'm thinking... . fuel tank pick up? Or hopefully an electrical problem.

So any input on possible causes/experiences would be greatly appreciated. Going into major TDR search mode, lol.

I've been through the inacurate fuel gauge 5 cent fix so I've been there done that with the fuel tank if that's the next step.

It just seems a little weird that it was an overnight thing, like lost prime, no indication of any potential problem while driving the truck, good idle, etc.

thanks in advance.

 

[CTD12V]

JoeyJ,



This may be a stupid question, but did you try priming and bleeding the fuel supply system (not the injectors, although if you totally ran it dry you might need to do that now, too)? My truck is very hard to start after just changing the fuel filter if I don't prime and bleed it first. Since it sounds like you had a lot of things open and places for air to get in the system, maybe your transfer pump wasn't pushing enough fuel at idle to overcome an air pocket, causing the engine to die while you were checking for leaks. I may be way off base, but it's just a thought. Good luck,



CTD12V

 

[JoeyJ]

Monday Update:

Thanks CTD12V... . tried this but still have the same results. Truck runs for about 5 mins then dies. Much fuel leaking from the pump itself. Appears to be coming out of the weap hole. Every other area of the pump is dry. It continues after the truck dies, also.

I'm looking to pickup a new pump today and a water sensor as it's dripping a little, as well.

I'll let you know how it goes.

 

[Joe G.]

Try changing the water sensor first and see if that takes care of the problem. If it does not then try the lift pump. I suspect that the lift pump is ok.

 

[JoeyJ]

Hey Joe- I watched very carefully to see if any of the fuel dripping from the water sensor was hitting the pump and it was not. I even went so far as to wrap rags around the primer button and the outlet line and both were dry after running. It's a pretty constant drip, about 4-5 drips per second, where as the water sensor is maybe 1 every 10 secs and is coming from the dump valve so it drops straight down to the ground. It really looks like it's coming from the weep hole. Even when I pulled the pump that was the only area that was wet. I ordered the water sensor today and the pump is in stock so I can pick them both up tommorrow at the Cummins dealer so I've got one more night to experiment, lol.

 

[JFaughn]

Just went through some of this , my 1st symptom was a loss of millage [ 1 1/2 mpg ] .
The next was when the tank got below 1/3 , it was hard to start , needed throdle to start .
The diff, between yours & mine was no leak , to fine the leak I made a pressure fitting for supply side - tank , lines & hoses , lift pump , fuel heater , ect. , this is all vacume so no fuel leaks becouse the leak is going to be air into the system [ vacume ] but then this will also test the low pressure up to the main pump ,
The fitting was a combination of parts put into a spare fuel cap - filler neck to tank , make sure that its an air tight seal so you can pressurize from the cap forward , be careful not to put in to much pressure [ at least 2-5 lbs , but not more than 15 lbs ] you do not want to blow anything apart .
now with the system prssurized use a flashlite to look over every inch of the system to the main pump , to find maybe mutible leaks , if you can find the leak detector chem. from maybe napa and then an ultra violet light source [ in the not so old days it could be black lite for your posters ] , thats if it isn't easy to see just squirting out .
I would do this before any parts money is spent , so you only buy what you need .
Now with the leak fixed you can test for fuel pressure at the fitting pitchered on page one ,
But it can be low and not the lift pump , it may be the overflow valve .
I took my pump apart and found an check valve missing part of the retainer , and all the the check valves were weak , after putting in the L. P. I checked the fuel pressure and it was a little low , about 20 lbs. , so I put in a know good used one , pressure went up to 37 lbs.
So I bought a new one , and saved the old one to make a new fuel pressure testing fitting .

 

[JoeyJ]

Latest Update: Well I picked up a new pump and water sensor and went at it Sat. Got the pump installed with pre-heater minus the heater (thanks Joe) and it may have been a source for at least some of the air. I went to install the new rubber line from the heater to the pump and... ... ... ..... they've changed the pump. It's a Cummins part but the area of the pump where the input fitting screws in is about an inch shorter so you can't install the line without crimping it shut. So pull it all off again to get the inlet fitting off and to the hardware store for some brass adaptors to try and get it close to the "stock" location. Thank God my motorcycle's in good shape and it's not rainy in SoCal, lol.

So back at it tonight, hopefully no more land mines and I can report something positive, lol

 

[BigPapa]

Joey,



Had the same problem with mine. Read about it here:



https://www.turbodieselregister.com/forums/showthread.php?t=129209



Surely we're not the only ones that have had this problem but I haven't heard of anyone else talking about it.



Scott

 

[JoeyJ]

Thanks JFaughn and BigPapa... had to work late yesterday so I'm still down. Hopefully get to it tonight... damn daylight savings, lol. I hate having to do this in the dark in the driveway cause there's always one piece of hardware that tries to escape, lol.

 

[JoeyJ]

ALL DONE!!!

Got everything installed and primed. Good power and no leaks. The only issue is with the new water sensor. It's defective (light on) so I need to pull the filter and exchange for hopefully a good one, lol.

I'll try to add a picture of the misc brass fittings used to extend the new pump inlet asap. For now it's off to the grocery store after work... . hard to do that on the bike, lol.

Thanks again to everyone for their input.

joey