lift pump upgrade

[coxfmly]

I'm considering upgrading the lift pump when I install a new fuel filter on the frame. I have seen 2 pumps on line, one is modeled after a duramax pump and the other one has a brand of Walbro. Both pumps claim a significant increase in PSI while driving and both are plug and play. One difference is the duramax model is set up to pressurize the fuel system right before starting. seems like a good option, any thoughts??

Thanks

[bshull]

In my 95 burb I have a walbro, it is plug n play for the electric but you will need to plumb it in and mount it.

While I was at it I removed the tank sock and installed a racor fuel filter and heater pre lift pump. I also installed the relay controller from Kennedy diesel.

I wish I had a reliable fuel pressure gauge so i could tell you the pressure difference.

In my opinion, both pumps are way better than stock.

Brian

[DmaxMaverick]

I would NOT recommend the "Duramax" pump. It is only used before a start, or for filter priming, and NOT intended for continuous use.

Either go with the OEM pump, the Walbro (excellent product, but not OEM), or upgrade to something like Kennedy's pump(s). Cost = performance, in this case. His controller is a bonus.

[JohnC]

High pressure is pointless. There is a pressure relief valve in the injection pump that controls the system pressure. What you need is flow.

the '94 setup runs the pump when the starter is energized, so no fancy pre-start priming is necessary.

[DmaxMaverick]

John is correct. Pressure is irrelevant. Only the minimum pressure is required, and that is anything above zero under all conditions. Pump output is not infinite. Usually, when a pump's pressure capacity is increased, flow is reduced, and vice versa. Increasing both requires more power. Most vehicle electrical systems are marginal with OEM equipment at best. Adding additional load to a circuit is usually self defeating.

Also, the pump has nothing to do with when it runs. The pump is a dumb component. It runs when it's commanded to run (power sent to it). You can install any pump you wish, and if the rest of the system is left alone, the pump will run at the same time it has always run. If you want the pump to run at times it was not originally designed to run, you'll have to modify the control system, not the pump.

[coxfmly]

Since I have been having issues starting my Sub lately, I assumed the system wasn't getting the fuel pressure it needed when I cranked it over. The Sub always starts but it usually takes 3-4 attempts, doesn't want to fire like my 84. This is why I was looking int an upgrade.

In the last year I have changed out my lift pump and OPS switch twice. To fix the OPS issue I'm going with the Lift pump control harness from Kennedy. I have read that the factory pump doesn't have a very high PSI. I assumed a higher PSI would help on start up, this is why I was looking into a lift pump upgrade.

I often wondered if the charging system was up to speed. My 84 always sounded really strong when starting. My 94 doesnt turn over as fast and feels labored? feels It alwasy cranked

[coxfmly]

Wonder if a higher apm alternator or new starter would help things out?

[HH]

I often wondered if the charging system was up to speed. My 84 always sounded really strong when starting. My 94 doesnt turn over as fast and feels labored? feels It alwasy cranked

What kind of shape are your starter and battery cables/connections?

[DmaxMaverick]

Wonder if a higher apm alternator or new starter would help things out?

Unless your starter is used up, no. The alternator won't help starting. It's job is simple, and is done and over with by the time you shut down. Suspect the batteries, cables and connections long before a working alternator.

[coxfmly]

The batteries are about a yr old. The cables are factory and seem to be in good shape. I really don't care for the GM side mounts, tough to know how good the connection really is. Does anyone know of a company selling upgraded cables for a 94 sub. The cables on my 84 were replaced with a custom, larger set. Worked great but I would rather buy them vs custom making another set.

[a5150nut]

SS bolt and double nut to mount your cables. I just cut the rubber from around my stock cables and they have worked fine. If you need to replace them, use welding cable and ends.