Lift Pump???

[DZinger]

All,



I started a thread last week about my fuel filter. I changed it as the truck would having difficulty starting. I got 400 miles on that filter and the problem started again. I changed the filter and upon inspection, it was clean. I got about 300 miles this time and having the problem again. I turn on the ignition and fuel pressure builds to about 6-7psi but quickly drops to 2-3psi and the truck will crank but not start. If I cycle the key 2 or 3 times, the pressure goes no higher, but the truck starts ans runs fine with 7-8psi on the gage and no signs of lack of power. Tomorrow ends our vacation and we drive home towing the 5th wheel from Saint Louis back home - I am a little nervous about shutting the truck off during the trip.



Any thoughts? I am beginning to think it could be the lift pump, but not sure as there is 7psi or so once the truck is running...



Any advice or help is always appreciated!



Don

 

[rbattelle]

I think you're wise to suspect the lift pump, although you have the in-tank model which is generally pretty reliable. 7-8 psi is sufficient, as you've found.

Did you make it home?

Ryan

 

[DZinger]

Made it home - although I did not shut off the truck during any fuel stops. We shutit off when we stopped for dinner in INdianapolis, though. It still needs to have the ket cycled two to three times in order to start.

 

[jelag]

I have several trucks and have been up to date on this board... I can't remember a person who has had an in tank lift pump failure... .

I did have a problem with the factory wiring... on our 05, in the middle of no where... . driving along and it would just slow down and get better... and than slow down... I had bet money on a lift pump failure when I called the tow truck 30 miles out of town... .

An hour later the tow truck showed up and I'd gotten my lap top out and the manual, and did a lot of trouble shooting..... as I sat with the service tech in the dealer ship giving him this long story the mechanic went to work... I went to breakfast... . while eating the tech called, said it was a bad wire 3 feet from the pump which had been damaged in the loom... water from the road had gotten into it and the electrolysis had eaten it up... . tow bill $125. 00, not a warranty repair $100. 00, piece of mind that it wasn't a lift pump PRICELESS..... I have sitting next to this computer that 3" piece of wire...

Hope this helps. .

 

[DZinger]

I will look at my wiring. I just find it odd that the problem goes away very temporarily if I replace the fuel filter. It seems as though as soon as it meets any resistance (even though the filter is still relatively clean) it looses fuel psi. Once I have it started and it is running the psi climbs back to 7-8psi and stays...

 

[steved]

Since they introduced them, I've only read of one or two failed in-tank pumps... they seem to have actually hit the mark on this pump.



One thing that comes to mind... doesn't the in-tank pump have a pressure relief (pop-off) valve? I seem to remember guys talking about modding this to get more pressure? Could that have failed (pump runs but just returning the fuel to the tank?)...



Also, I thought it was normal for the lift pump to cycle on, then shut off... mine did that until I recently installed the Smarty Jr software... very noticeable when you have one of the older FASS.

 

[VolCTD]

Could it be a sticking FCA (Fuel Control Actuator)? Mine would start the rough idle problems and like you I would change the fuel filter and it would go away for a short while only to return. They are only around $125 from the Cummins store or I noticed Geno's Garage now sells them for $103. I don't have a fuel pressure gauge so I wasn't able to see if the psi changed any when my problems started.

 

[jelag]

I didn't mention that we have installed on all our trucks a 10 micron primary filter and a 2 micron secondary filter on the frame rail... we change these filters once a year and drain the water from the water trap on the primary filter every 6 months... . we've yet to have one of these plug up... . or lower fuel pressure... these filters must hold over a qt of fuel have lots of surface area...

I've tested some of the take out filters before we went to this system... . it was a very crude test where I'd plug one end and try and blow through the filter... in a lot of the cases, the old filter (stock filter) would be very restrictive and the new filter going in would be very clear... of course is not a valid test... . but just a rough guess... .

I have trouble thinking your getting these plugged up... but who really knows. .

 

[DZinger]

As far as the FCA, I had no rough idle or anything like that. I decided to take it to a friend that is a Dodge service tech to get his opinion. Wierd thing is that yesterday morning when I went out to start her up, I thought I'd try a one key cycle start. The pressure only went to 5psi, but did not drop, so I cranked and it started right up. All day the pressure got hiher and higher and everywhere I went, I started it with one cycle of the key as it should be. By the time I dropped it off with John, it was functioning fine. I will still let him go through it as it is a little unnerving to wondering when it won't want to start up... I will keep this thread posted as to his findings...

 

[JRMora]

I have several trucks and have been up to date on this board... I can't remember a person who has had an in tank lift pump failure... .

Jim,



LP #1 (engine mounted) failed at 80,000 miles in the middle of nowhere.



LP #2 (in tank mounted) failed at 29,000 miles... . also in the middle of nowhere.



Common theme - in the middle of nowhere.



I had hoped #2 would do better.



Juan

 

[DZinger]

OK - got the call from the tech - lift pump was bad - he changed it and cleaned the fuel tank - he suspects that I got ahold of some bad fuel...



Thanks to all for you input!



Don

 

[DZinger]

Picked up the truck last night. Runs great. Holds about 11psi from the lift pump until I hit the go pedal - drops to 8-9psi then rises again. Tech told me I did get bad fuel - black, sandy stuff in the tank - he cleaned out what he could and advises I change the filter after about 100 miles or so...

 

[steved]

black, sandy stuff in the tank

Since the pump is pre-filter, this is probably what killed your pump... running grit through it.



Have you checked to ensure your tank vents have been "fixed"?? That's typically where most think the sand/water enter the tank.

 

[DZinger]

Fixed? Help me out here... .

 

[steved]

Fixed? Help me out here... .

This will explain it better than my repeating it...



https://www.turbodieselregister.com...ssions/125393-check-your-fuel-tank-today.html