2005 in tank lift pump dead ???

[LHirshman]

Ita has been some time since I posted here until.....

Yesterday I had a sudden power loss going up hill. The tank was half full. I filled up and power returned. Thinking of what could be wrong, Fuel Filter, FCA or Lift pump, The next time I went to start the truck, I bumped the starter and no sound from the lift pump. My truck is a 2005 with 141,000 miles.

Do these in tank pumps fail? Tomorrow I'll try and diagnose the problem.

So here are my questions, where is the fuse for the lift pump and where is the Lift Pump relay?

How many connectors are there to the tank and how accessible are they?

Why is the significance of half a tank when the lift pump is not working?

I appreciate any help and advise.

 

[p-Bar]

If it moves it's going to fail some time. The intank is a fairly stable pump , yours is the first I have heard . There is a flexible line on the pump that could have ruptured and is sucking air so that would be the full tank /half tank issue. My 04.5 was converted so it's not the same as yours in regards to wiring. I'm sure there is a fuse and relay. Pull the fuse cover and look at the pic for fuse. The pressure could have been up so it wouldn't bump. Try opening the water bleed at the fuel filter cannister leave it open and turn the key on see if it flows.

 

[LHirshman]

I think you hit the nail on the head. Last night with approximately half a tank, the motor stalled in our driveway, which is sloped. This morning, between raindrops, I filled the tank to almost overflowing and then tried to start the truck. After cranking for about 10 seconds, I stopped and could hear the lift pump. The second attempt at cranking finally started the motor. I read somewhere that the mechanical pump, built into the CP3, has sufficient suction to be able to draw fuel from the tank. Looking at pictures of replacement pumps there is indeed a coupling device between the two sections of hoses midway up the lift pump unit.

So now for some questions. Will running with the CP3 drawing fuel without the lift pump providing pressure damage the CP3?

Is there no other way to get the lift pump assembly out of the tank without dropping the tank or raising the bed? Since I only want to get into the tank this once, what is the most cost effective and reliable way of putting an external, to the tank, pump using the, Draw Straw, sold a t Genos Garage?

 

[p-Bar]

The CP# is designed to draw from the tank without the lift pump operating . Basically you can limp home guys have done it. The aftermarket pumps seem prone to problems and if your not hotrodding the truck go back to the in tank it's really the best as probably all vehicles today use the in tank method. You will have to drop the tank but it's a good time to clean the debris that has collected over the years. I'm sure there are some pics on doing this if you do a search.

 

[p-Bar]

Doing some research the intank pump is quite expensive so plan B would be to do a draw straw and go with a Holley blue or red pump and if it were me I would buy an extra and keep it in the truck.

 

[LHirshman]

Looks like I'll be dropping the tank. It will be a while till I get to it. When it's repaired and all is right with the world, the results of this endevour will be posted here. Thank you for your help.

 

[p-Bar]

OK sounds good you may want to do the tank vent kit which makes it easier to top off your fuel tank . I'll get you info if you wish.

 

[LHirshman]

Yes as long As I'll be under there, the vent kit sounds like a plan. Instead of the Holly, what do you think of the External Replacement pump Genos sells for the earlier common rails? Is it reliable?

 

[p-Bar]

Checking on the tank vent for you. Let's see what others are saying about lift pumps.

 

[TCDiesel]

Stick with the in tank Pump, the external ones look like that option is the way to go but its not, unless you want more power. The external ones fail often and are subject to conditions the in tank will never have.

 

[cerberusiam]

CP-3 is not designed to pull adequate fuel from the tank in a Dodge application, lines are too small and the rise too high for adequate suction only. Never worked well on GM product and works less well on a Dodge.

There is a overflow valve that regulates pressure after the pump and of course the line itself which is plastic. Both have been know to fail randomly. Also, the canister will tend to plug up with asphaltenes over time and restrict the fuel flow to the pump when fuel level drops. Since the pump is at the bottom and the failures are downstream you should see issues even with the tank full. Would need an LP pressure gauge to see that though.

The truck is 12 years old, probably time to consider a replacement of the canister and plumbing.

 

[AEdelheit]

Speaking from personal experience the pump on the CP3 can pull from the tank until it looses prime then it will not be able to and leave you on the side of the road. Dropping the tank is actully pretty easy and so is lifting the bed up so neither option is too bad of a job.

 

[LHirshman]

From your replies it would seem that replacing the in tank unit is the most reliable fix. There are quite a few choices out there, which aftermarket manufacturer of the in tank (pump, sender, etc.) would you all recommend?

 

[TCDiesel]

I recommend OEM...BC its difficult to replace and can leave you stranded the aftermarket just to risky.

 

[cerberusiam]

All in all, I would go with a FASS and a bypass loop. A failed in-tank pump, for whatever reason, is leaving you dead in the water with no options. It has to come out and be replaced and when\if it does fail it will be with so much stuff in the bed that it will be a major problem, just the way the odds work for me anyway.

I believe even if the FASS motor dies, as long as the system does not get drained the CP-3 wills till draw thru the FASS pump, a bypass loop would make sure that would happen but keeping it full is another question. A failed external pump using new 1/2 lines from the tank to the OE filter housing will usually allow you to get back to civilization. A failed stock pump with stock lines has a much greater chance of stalling right there.

External pumps quite a bad rap but talk to the guys at Genos and get some more info on the FASS. My impression from talking to them is the bulk of the failures are bad installs. Since they carry the pumps pretty sure they will get you back on the road as soon as physically possible if needed.


Sometimes it not just the item but the vendor support that can be critical.

 

[LHirshman]

It would be nice not to have to drop the tank of raise the bed (not possible for me). If I go with the FASS, I found, from FASS, the STK-5500BO Sump Kit.
It mounts on the outside bottom of the tank, requiring a hole to be drilled on the bottom of the tank right below the in tank unit. Has anyone experience with this Sump Kit?

 

[cerberusiam]

Sumps are not a recommended solution, but, if there is no other way it is an option.

 

[LHirshman]

There are many different aftermarket external pump/filter options out there. They advertise 3/8" and 1/2" fuel lines. Some say they bypass the stock fuel filter and go directly to the CP3. One of the FASS units, for an '05, at Geno's, is that type. So what is the stock fuel line diameter, 5/16"? I want the fuel heater as close to the CP3 as possible which means using the stock filter. Genos has a FASS fuel pump which is external, no filters, will it connect to the existing fuel line to the stock filter? I'm confused!

 

[cerberusiam]

None of them HAVE to bypass the OE filter and unless you are building a race truck you should not do that. Multi-pass filtration is still the best solution available and for a street driven close to stock truck that should be the aim. Any of them can use any size line you want, you can put 1/2 lines and Holley black pump in there if you want so don't get confused thinking those are hard requirements.

The reason to use 1/2 lines from tank to the CP-3 is for flow and the ability to siphon if there is a pump failure, the larger the lines the easier it all will work. Stock you don't necessarily need the flow but any reduction is flow friction is going to enhance the results, and from the FASS standpoint, longevity. It is easier to suck thru a big straw than a small one and that is where it will help the external pump live longer. That really goes for any pump or combination thereof.

The HPFP that has no filters is not a bad solution either, but, you really should add another WS after it and a 3 um between the OE housing and CP-3. The HPFP can be plumbed into the existing lines and should work fine, but, you need to remove the in-tank pump and replace it with a pump-less canister or it really defeats the purpose.

 

[TCDiesel]

1/2 line is not needed, All the passages Manifold/Body/GP in OE CP3 are 7/32 & 11/64 3/8 line more than suffice. OE GP produce 24Hg @ 1700RPMs modded GP can produce 30-32HG@1700RPMs GP on other model CP3s can produce 40HG, That's why is so important to leave Factory Canister... I'V seen those aftermarket Filters after Factory Canister get complete collapsed...If You want to know the Facts on fuel systems call someone that has decades of knowledge and experience and will gain your trust Via conversation, lots of misunderstandings rampant on forums and web that will/may cost $1000s in repairs if followed.