3g Lift Pump?

[hoverlover]

3rd GEN Lift Pump?

Does anyone know if the 04's still use a lift pump? If not how do they get the gas out of the tank to the engine?



Thanks!

 

[lschultz]

They don't get the gas out it is diesel they run on. I had to say that. I am not sure but starting with the 03 there might be a different setup. Have not really looked at mine to see if there is a lift pump but I think they changed the set up they might not call it a lift pump but since these run higher fuel pressure something is different. There will be somebody that responds to this that knows for sure.



I think they have some kind of pump(don't know what they call it)mounted on the fuel filter housing. I remember my son was looking at it the last time I changed fuel filter. He just had to replace his lift pump on his 99 a coupled weeks ago. He changed fuel filter and could not get it started. The original one made it to about 150,000 miles.

 

[Dean Upson]

I don't know about the lift pump, but I saw a new '03 all torn apart yesterday with a bad fuel pump . It sure made some interesting noise .

Dean

 

[mgonske]

I'm no expert, just repeating what I remember of what I've read here, since there haven't been any further replies. The lift pump on the '03s is only necessary to prime the injection pump (CP?); once running, the injection pump is capable of drawing it's own fuel without a lift pump. That being said, it is reported that at increased HP levels (I believe 400 HP is the number Keith Locklier(sp?) at Diesel Dynamics cites), the stock fuel lines are not capable of flowing fuel at the rate at which the injection pump can draw, resulting in potential starvation (corrected by larger fuel lines, and what the heck, a supplemental lift pump).

 

[Casey Balvert]

Interesting, our EMS First Response truck just quit while running down the road. Dealer says it is the lift pump (the one attached to the fuel filter canister). I too thought that the injection pump could draw its own fuel. Anyway, dealer says that DC is aware of an issue with these pumps. Must be pretty rare, as I have not seen much regarding pump failures on any of the forums. The dealer claimed that some of the fuel companies are experimenting with diesel additives and that may be causing the problem. Stated last year he had problems with a local fleet of trucks using Shell. Seems pretty off the wall to me. I am going to check around a bit on this one. Dealer did promise to keep me updated on what DC comes up with then they inspect the old pump. In the meantime the truck is down waiting for a new pump. I will post my findings when I get them.



Would this be a good reason for using a lubricity additive? I have refrained from using anything for fear of damaging the injectors.



Casey

 

[TCDiesel]

Pump

The electronic pump only primes the cp-3 it will pump to 1to2 seconds to build pressure,If pressure drops it will engage for a sort time to build pressure again, it will not run continuously. I need to clarify this,at times when a vehicle will not start and you do not hear the lift-pump ,the pump must be the problem ,NO once it builds pressure it will not engage again until pressure drops. check out BigCarl64 post the spec"s are their.

 

[Jeff_K]

The electronic pump only primes the cp-3 it will pump 3 to 5 seconds to build pressure,If pressure drops it will engage for a sort time to build pressure again, it will not run continuously.

True, before the engine starts. Once the engine starts and is running, the lift pump runs constantly feeding the cp3 pump. I have replaced my lift pump with the DD pusher pump kit because I could draw the fuel pressure down to 0 psi on WOT runs with the EZ on level 3. The stock lift pump would make about 7-9psi at idle, but with the DD kit I now have 14-15psi at idle and you can definitely hear that Carter pump running. As far as I am concerned, it is cheap insurance to get rid of that stock lift pump right away if you are doing any sort of mods.

 

[rbattelle]

I believe maybe the CP3 can pump it's own fuel from the tank, but perhaps not with a fuel filter in the way. I mean, it can develop a vacuum at the inlet, but not quite enought to suck fuel through the filter and lines, which would explain why a truck with a bad lift pump might not run.



Casey,



Like you, I have refrained from using any additives for fear of the reaction from the injectors. I will continue to refrain until I'm satisfied that there won't be trouble. If there is anything about this engine I fear, it's the sensitive injectors.

 

[Blakers]

At what pressure does diesel fuel boil or vaporize at a summer fuel operating temperature? Say 150 deg F.



Anyone know?

 

[TCDiesel]

Pump

I have been trying to post the information from the 03DRM,The file will not post correctly. It is not readable I will keep trying.



BigCarl64, posted the information.

 

[Casey Balvert]

By the way. The truck is a stock SO that we took delivery of last April. The taxpayers have not added any mods. Since I was also under the impression that the lift pump wasn't necessary to keep the truck running, I was surprised when the dealer explained the pump as the cause of the truck just stopping. Somehow I am sceptical of his explanation but time will tell. It was rather cold that day, well below freezing. As well, some dope left all the radio equipment on overnight and killed the batteries the day before. And we know what low power will do to the electronics.



Casey

 

[BigCarl64]

FUEL TRANSFER PUMP - from Service Manual

OPERATION

The purpose of the fuel transfer pump is to supply

(transfer) a low-pressure fuel source: from the fuel

tank, through the fuel filter/water separator and to

the fuel injection pump. Here, the low-pressure is

raised to a high-pressure by the fuel injection pump

for operation of the high-pressure fuel injectors.

Check valves within the pump, control direction of

fuel flow and prevent fuel bleed-back during engine

shut down.

Maximum current flow to the pump is 5 amperes.

With the engine running, the pump has a 100 percent

duty-cycle with a minimum pressure of 11. 5 psi.

The transfer pump is self-priming: When the key is

first turned on (without cranking engine), the pump

will operate for approximately 1/2 second and then

shut off. The pump will also operate for up to 25 seconds

after the starter is engaged, and then disengaged

and the engine is not running. The pump

shuts off immediately if the key is on and the engine

stops running.

The fuel volume of the transfer pump will always

provide more fuel than the fuel injection pump

requires. Excess fuel is returned from the injection

pump through an overflow valve, and then back to

the fuel tank.

 

[r Hollander]

At last years May maddnes in one of the seminars a Cummins

guy said that the lift pump on the 03s could stop in a position

that will block the fuel flow .



Ralph

 

[dan.poitras]

Originally posted by Casey Balvert

By the way. The truck is a stock SO that we took delivery of last April. The taxpayers have not added any mods. Since I was also under the impression that the lift pump wasn't necessary to keep the truck running, I was surprised when the dealer explained the pump as the cause of the truck just stopping. Somehow I am sceptical of his explanation but time will tell. It was rather cold that day, well below freezing. As well, some dope left all the radio equipment on overnight and killed the batteries the day before. And we know what low power will do to the electronics.



Casey

Casey

All of our fire and ems equipment are equipped with master shutoffs so battery rundown is minimized.

 

[dieselpilot1969]

my 03 will only have a lift pump till it goes out, then gonna get a fass or equivelent

 

[Casey Balvert]

I am suspicious of the electrical system. I while back someone posted that their alternator went bad and the truck quit. It wouldn't restart until the batteries were fully recharged. Since they had allowed the batteries to go stone dead and since the tech told me the batteries were still down today (he was charging them up one at a time) I suspect all of this may be the result of low voltage. Or else it is one hell of a coincidence. These pumps just don't go bad, or at least it is rare. They installed the new pump today and are waiting for a connector hose. They are shipping the old pump to DC for analysis. It will be interesting to read the findings.



Casey

 

[Joseph Donnelly]

With key on but engine not running, the lift pump runs for a bit then stops. It runs continuously when the engine is running. I have seen the fuel pressure drop like a rock to zero with just a pressure box on the truck. The Diesel Dynamics pump kit fixes the problem. Because it uses the stock wiring harness and connector, it will behave like stock as to when it runs or doesn't run, a good safety feature. There is a small gear pump on the CP3 high pressure pump, but I wouldn't rely on it alone.



At a minimum, I'd check pressure if you added any power.

 

[Blakers]

Originally posted by Casey Balvert

I while back someone posted that their alternator went bad and the truck quit. It wouldn't restart until the batteries were fully recharged.

That's what I don't like about this new technology. Back before this "improved" technology, a diesel never even needed a battery to run - only to start. Once it was running, it would keep on running as long as it had fuel.



Now someone's bright ideas have made the diesel engine much less reliable! I miss my 12 valve.

 

[Casey Balvert]

I really think this was a fluke that resulted from someone's neglegence. FWIW I have had no problems with my own truck at all.



Casey