2nd Gen Non-Engine/Transmission in tank fuel pump weak,can i add a carter?

[GreggNoble]

hi, my 2001 3500 4x4 has the in tanks lift pump conversion but that pump is now getting weak too, would it be possible for me to just buy an origional carter (on engine) pump and use it along with the one in the tank simultanously?

 

[rjrkihap]

Hi Gregg

Yes and No. Yes,you can add another fuel pump. It will act as a compound pump such that if the new pump is set up for 15psi and the old pump is only putting out 2psi, you will end up with approx. 17psi. The problem occurs if/when the in-tank pump fails. It will create an obstruction to the second lift pump. This will lower the efficiency of the second pump (lower psi and make it work harder) and drastically shorten the second pumps life.

If you go this route, I would recommend against using a Carter lift pump mounted in the original location. There are several aftermarket pumps that will last a lot longer and can be mounted near the tank.

Your best bet (long term) would be to bypass the in-tank pump by either removing it or adding a Draw Straw. Then use a FASS or Air Dog as you primary and only lift pump.

Good luck.

 

[GreggNoble]

Thanks,that sounds like good asdvice. money is an issue to me so i`m thinkin in the cheapest way ha ha ha h but isn`t there a simpler &cheaper fass pump out there now? one that has no filter attached i think i saw it somewhere.

 

[rjrkihap]

FASS makes 2 non-filter pumps; the HPFP which is a FASS pump without any filters attached and the Direct Replacement Fuel Pump which is a smaller pump that was designed to be a direct replacement for the factory Carter lift pump. Either pump will be superior to the factory Carter Lift pump.

Good Luck.

Ron

 

[GreggNoble]

thanks ron do you know the exact name for the model that bolts on the engine so i can look for it here in canada?

 

[rjrkihap]

I believe it's the FASS DDRP (Dodge Direct Replacement Pump) Description Catalog .

When you had Dodge install the in-tank pump, what did they do to the original fuel lines, electrical connections located on the side of your motor? Is it even possible to install a lift pump where the original Carter pump was located?


Ron

 

[Arctic Taco]

I think Geno's has a relatively inexpensive kit for relocating even the fass DRRP to the a spot near the fuel tank on the frame- a better option to be sure.

Cheers

 

[WilsonF]

Disagree

Hi Gregg



Yes and No. Yes,you can add another fuel pump. It will act as a compound pump such that if the new pump is set up for 15psi and the old pump is only putting out 2psi, you will end up with approx. 17psi. The problem occurs if/when the in-tank pump fails. It will create an obstruction to the second lift pump. This will lower the efficiency of the second pump (lower psi and make it work harder) and drastically shorten the second pumps life.



If you go this route, I would recommend against using a Carter lift pump mounted in the original location. There are several aftermarket pumps that will last a lot longer and can be mounted near the tank.



Your best bet (long term) would be to bypass the in-tank pump by either removing it or adding a Draw Straw. Then use a FASS or Air Dog as you primary and only lift pump.



Good luck.

I agree with everything you say but the 17psi Years ago in Hydraulic school we were tough that no matter how many pumps you have system pressure will be at the highest rated pump. The volume, however, will be the the combination of all the pumps.



Floyd

 

[HookMeUp]

I have been running the in-tank pump and the carter mounted on the frame rail for over 2 years now. I would develop 25psi, so I put in a bypass relief valve. Now I see 17psi at idle and 14psi at full trottle pulling the trailer up a grade. I also have the 1/2" fuel line kit installed. It's been a good setup so far.

 

[rjrkihap]

Wilson, I (in theory) agree with you, however I remember reading numerous posts like HookMeUp's, where people were developing high pressure when adding a second lift pump to the system (keep the weak engine Carter pump and then adding another Carter near the tank). I always thought this was a result of compounding the fuel pressure. I guess I'm not knowledgeable enough to understand how/what is actually happening. Any help explaining this would be greatly appreciated.

Thanks

Ron

 

[mhenon]

It's just like you and HookMeUp have said. The pressure of the two pumps in series is the sum of their pressures.

My system is exactly as HookMeUp's; intank (9psi) to a Carter (16psi) for a total of 25psi. I too had to install a bypass from Glacier to regulate the pressure to 15psi.

A failed intank will drop the pressure but the truck will keep going. My Carter would still make about ~12psi with the intank pump switched off. I agree though that running it long term with a dead intank would be asking for trouble.

For me at least it's been a pretty good fuel system and you can't hardly make the pressure twitch regardless of load. I'll think about upgrading the fuel system when I run out of spares. With two new Carters and a spare intank on the bench I should be good for awhile.

Mike

 

[Hammer]

Have any of you had the "in tank" fuel pump system ever out of the tank and seen how restrictive it really is?. If you did then you would rid yourself of it completely and go to another idea. When your trying to send fuel flow through a hole thats not much larger than a ink pen point I'd say there has to be and is a better solution.

 

[mhenon]

Have any of you had the "in tank" fuel pump system ever out of the tank and seen how restrictive it really is?. If you did then you would rid yourself of it completely and go to another idea. When your trying to send fuel flow through a hole thats not much larger than a ink pen point I'd say there has to be and is a better solution.

I've had several intank pumps in my hand and have run one in a bucket of fuel once to check the flow. As Richard at Glacier Diesel Power discovered the pump moves quite a bit of fuel but most of it gets bypassed before it leaves the tank. We're left with 5-8psi to feed the VP which isn't enough.

As a pusher though, feeding a second LP, it's a great little pump. It keeps a nice head of pressure to the Carter and the two in series provide more fuel than you'll ever need.

I agree though that there are better systems out there. I just found myself with a new intank pump (VP swap) and 3 spare Carters. Thought I would go through the Carters before dropping $500 bucks for a new system.

Still going strong at >50K miles now.

Mike