Stock lift pump psi Qs

[Cheatham]

Just bought a 2001 2500, 307 000 miles automatic, very clean and well maintained, I installed a mech fuel psi gauge, at idle 8 1/2 psi, at 60mph about 1600 rpm its at 7psi, is this low enough to hurt the vp44 ? iv hardly driven it as I am getting little stuff fixed first, iv ordered a Airdog frrp, its a stock motor and will stay stock and used as a daily driver about 6 000 miles per year and occasional light towing will this pump be suffiecient ? I don't know the maintance history of the truck as far as the vp44 being replaced nor the carter style lift pump.

[Texas CTD]

Lift pump pressure is too low. It needs to be above 10 PSI; ideally, between 14-20 PSI at all times.The 100 GPH pump is plenty for a stockish truck, although Airdog/Raptor have not been the most reliable pumps lately. . .

[Cheatham]

New pump is installed, it had a Carter maybe it had been changed as the bolts and fittings were barely tightened got it started and adjusted pressure to 15psi, is this enough ? I replaced the breather tube with a longer one and installed in a bottle to catch any oil, now I pulled the fan and shroud to clean the built up mess, glad to have found this site with suggestions and answeres.

[kingairc90c]

On the return side of the vp44 plumbing there is a banjo bolt pressure check valve that opens at 14psi. 15 at idle is fine, 17psi would be better. Wide open throttle or around 3000 rpm it benefits the vp44 to have 15psi. The reason is the vp44 is fuel cooled. If the pressure check valve is not allowing fuel to flow through it then the vp44 is not being cooled. The vp44 is also fuel lubricated so a fresh supply of fuel that is cooler helps with this too. As far as an upper limit, don't exceed 20-21psi as the internal diaphragm doesn't take to well to pressure above 21psi. I know some people run higher pressures and claim no problems. This may be true, but I have rebuilt pumps that failed from too much pressure. Hope this helps a little.

[Cheatham]

On the return side of the vp44 plumbing there is a banjo bolt pressure check valve that opens at 14psi. 15 at idle is fine, 17psi would be better. Wide open throttle or around 3000 rpm it benefits the vp44 to have 15psi. The reason is the vp44 is fuel cooled. If the pressure check valve is not allowing fuel to flow through it then the vp44 is not being cooled. The vp44 is also fuel lubricated so a fresh supply of fuel that is cooler helps with this too. As far as an upper limit, don't exceed 20-21psi as the internal diaphragm doesn't take to well to pressure above 21psi. I know some people run higher pressures and claim no problems. This may be true, but I have rebuilt pumps that failed from too much pressure. Hope this helps a little.

I will adjust it to 17psi. Ive also wondered why not use a pump like a holley, aeromotive racing gas pumps and a regulator if needed ? they can handle methanol/gas so I don't see why not diesel ? also was wondering why not move the block pump closer to the tank lenthen the wires and fuel line ? then the pump doesn't have to pull so much and can push the fuel.

[bry1216]

New pump is installed, it had a Carter maybe it had been changed as the bolts and fittings were barely tightened got it started and adjusted pressure to 15psi, is this enough ? I replaced the breather tube with a longer one and installed in a bottle to catch any oil, now I pulled the fan and shroud to clean the built up mess, glad to have found this site with suggestions and answeres.

A few questions: Which side of the fuel filter is your gauge attached to? What type of new pump did you install?

[Mopar1973Man]

I will adjust it to 17psi. Ive also wondered why not use a pump like a holley, aeromotive racing gas pumps and a regulator if needed ? they can handle methanol/gas so I don't see why not diesel ? also was wondering why not move the block pump closer to the tank lenthen the wires and fuel line ? then the pump doesn't have to pull so much and can push the fuel.

Holley pumps tend to fail in the motor brushes or the shaft seal. Back in the day Holley blue and blacks were very common. But failure was also very common too. Vulcan Performance Big Line Kit is what will do that exactly as for moving the pump towards the fuel tank. Includes all the electrical for the pump, plumbing and even the mounting bracket. But all this never cured the lift pump life span issues. Most the pump couldn't hold up to the additional strain during the cold winter months as the fuel thicken up to nearly jello state. AirDog and FASS where the first two pump to come forward that held up to weather conditions.

[Cheatham]

A few questions: Which side of the fuel filter is your gauge attached to? What type of new pump did you install?

I got the banjo fitting with the 1/8npt and I had hi psi hoses and gauges already so I connected at the vp pump line going in after the filter I bought the Airdog 100 it has all fittings and is ez to install. that makes since about the fuel at cold temps which the auto perf pumps would have problems, im on the Tx Gulf Coast so cold temps hardly exsist here lol.