when the lift pump goes out will it start making a loud knocking sound and increase with rpm? I can hear this in the cab with windows up and around driver's side fender well area.

 

If the spring that keeps the lift pump's actuator arm against the cam breaks or gets weak the arm will slap on the cam and make a tapping sound.
Before replacing the pump make sure the noise is indeed coming from the pump, a long screwdriver, pipe, etc on the pump and the other end on your ear will isolate the noise. Or better yet buy an automotive stethoscope, cheap at most autoparts.

 

would it make a tiking noise from the oil fill what i mean is when you take the oil fill cap off it makes some wierd tiking clanging noise you put it back on you dont heard it any more, could that be a lift pump or what

 

Sure, the sound could echo though the engine. The pump actuator slaps on the cam that runs up front to right behind the oil fill.

 

i will try doing the test you said eailer and see is there anything easy that would make that noise

 

If your fuel tank is creating a vacume from not venting properly it can cause your LP to work harder than it needs to which will make a ticking noise.

I have had this happen on two different trucks now. Eliminate the vacume in the tank and the ticking goes away.

 

my fuel tank was creating a vaccum because of the little red cap on the vent on top of the fuel tank. i removed the cap and vaccum was gone,but all that vacumm after 188,000 miles may have made my lift pump go out.Bill what do you and rhino think could the vacumm after that many miles make the lift pump go out?

 

Don't know about the vacuum causing the pump to go out, the fill cap also vents vacuum.

I've ran across one truck where the owner was unfortunate enough to have both the vent on the tank and the cap vent plugged (actually it was a aftermarket locking cap made for a gasser that didn't vent). The first time he went to fill up after he installed the locking cap he couldn't get the cap off, it was sucked on so tight. The vacuum creeped down after sitting overnight and he was able to switch back to his old cap and go fill up. Got to the station and and was only able to put 15 gallons in a tank when the gauge was on E, the vacuum had collapsed his tank. That's when I came in, pressurized the tank with compressed air to pop it back out.
Moral of the story, these lift pumps really suck.

188k is a good long life for a lift pump.
Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349

has lift pumps for around $100. While you're at it buy an overflow valve from him just to have a spare.

 

188K on a lift pump for 12v? That don't seem right at all. I must be very lucky at 331K and still ticking.

..PT..

 

Both mine have over 200k and may make it to 500k, who knows?
Lift pumps are a wear item like water pumps, starters, etc, they will eventually go out.

 

Bill;
I was going to order another overflow valve from Marty. Glad you mentioned the lift pump. I probably need one as the truck is a slug over 2,000 rpm these days.

Have you tried any of these lift pumps? I know some folks comment that his overflow valves hold more pressure than stock.

 

Is more pressure better?

 

I installed one of Marty's pumps in a '97, it looked just like the stock one that came out. You can also pick up lift pumps from a Case tractor dealer for a much better price than Cummins.

His OF valves are about 2 psi higher at idle.

More pressure is ok to a point but I've heard of some people with performance problems with pressure over 45 psi. Main problem with overly high fuel pressure is the potential for leaks and split fuel filters.

 

Thanks Bill, is there a case part #, or do they cross to a cummins part #?

 

I've heard and read a lot of mixed comments on the higher pressure overflow valves.
Some say it makes too much noise at the injection pump and remove it.
Others say it makes the lift pump noisy (noisier).
Others are very happy.

I've heard the 45 psi value before. I wonder at what pressure, fuel starts seeping past the plungers and mixes with engine oil.

I was at Cummins yesterday and forgot to ask pricing on a lift pump. Odd I forgot as we were talking about the Cummins campaign to change out 24v lift pumps. I'll call tomorrow and compare with local IH (Case) dealer, too.

-John