Cummins swap, lift pump?

[major519]

For those who have done the 5.9 Cummins swap, is it a neccessity to install the lift pump as used on the original Dodge pickups?
I am a diesel novice, please excuse my ignorance.

[major519]

For those who have done the 5.9 Cummins swap, is it a neccessity to install the lift pump as used on the original Dodge pickups?
I am a diesel novice, please excuse my ignorance.

[maskale]

Never done a cummins. But going with yes u need a lift pump. It doesn't have to be the stocker. You can add an electric pump on the frame near the tank or under hood if it can suck that far. Most electric pumps are pushers, not suckers. Be sure it meets the specs of the stock pump.

[ken ruhland]

Definitely need a lift or transfer pump which they are sometimes called. I have installed a few by the name of raptor on factory dodge trucks that bolt onto the frame. Also a pressure warning light that goes into the factory filter housing is a good idea. The reason for the light is if your pressure gets low it will hurt your main high pressure pump. Plenty of aftermarket options for the pump and light.

[tndonor]

Yes you need a lift pump. People use the aftermarket lift pumps on 24 valve (98.5-present) because the injection pumps are not mechanical. Under high fuel flow from a chip, the fuel pressure drops and the pump burns up. Also, fuel cools the electronic pumps.

There are 2 mechanical pumps. The VE (89-93) and P7100 or P pump (94-98). The VE pump is cooled with fuel as the electronic pump is. They use a diaphragm lift pump. They can be upgraded to a low pressure piston pump if you plan on adding power.

The p7100 is oil cooled. It is the work horse, makes the horsepower, etc. It uses a high pressure lift pump. For reference, I have a compounded Cummins in my 715. It will make about 500 horsepower give or take. It uses a stock lift pump.

The problem with not using the factory lift pump is 1, you have to make a plate to cover the hole (lift pumps 89-98) are driven off of an eccentric on the camshaft. Second reason is one more thing to go wrong. There is really no practical use for one on a 12 valve. Most people are using the electronic lift pumps as insurance as to not trash their injection pump on 24 valves.

[glenn]

The 24 valves with the VP44 pump had an electric lift pump mounted on the side of the block. It didn't like the vibration or the heat and would quit on a fairly regular basis. The bad thing is that when it quit the engine would still start and run but the IP wouldn't be getting enough diesel to keep it lubricated and cooled. The usual way to find out is your truck quits and gets towed to a shop or you go to change your fuel filter and your truck won't ever start again without the electic lift pump to prime the filter. The truck getting towed usually means you get an upgraded lift pump and IP, the other way is usually just a lift pump and possibly an IP in the not to distant future depending on how long its run with no lift pump working. Dodge came up with an in tank electric lift pump as a fix for this problem on both the VP44 trucks and the common rail trucks.

[Barrman]

What year engine do you have? The mechanical IP 6BT has a mechanical lift pump on the block. You do need it.

I would imagine the 98.5 and newer 6BT electronic IP will need its lift pump as well. I just don't know if that is an electric in tank pump or mechanical pump on the block.

[major519]

Looking at the purchase of a 1993 6bt 12v.

[major519]

So, on a 12v '93 cummins, the block mounted mechanical lift pump is what is normal in the stock application?

[Mikel]

So, on a 12v '93 cummins, the block mounted mechanical lift pump is what is normal in the stock application?

Yes.