j_martin

My money's on this one.

Crazymonkey

Just looked it up in my manual:

"Properly operating lift pump will pump a minimum volume of 0.75 liter (0.70 US quart) of fuel in 30 seconds at engine cranking speed."


Which I would assume translates to 21 gallons per hour, but that is just at cranking speed. I didn't see anything in the manual at idle speed

Im looking right now to try to find out the correct flow rate before buying an electric pump today.

Thanks!

Crazymonkey

I happen to have a Carter P61294S inline fuel pump laying around with specs:

10-15 psi
30-35 gph

Im going to hook that up today, & post my results later.

Thanks again for all the help!

Crazymonkey

74 degrees today. Started my engine, showing 0 psi.

hooked up the carter pump.

applied 12v to the pump without starting the engine and 1 psi registered on my gauge.

started the engine with the 12v pump running & still showed 1 psi on the gauge.

assuming I need to find a better inline pump

j_martin

What does the pump do just into a gauge, no flow? Is the regulator in the IP nackered?

edwinsmith

If you have a VE injection pump, whatever you do don't let the pressure at the inlet to the Inj pump go over 15 psi. If you do you could blow out the front seal and fill your crankcase with diesel fuel. Don't ask me how I know.

Crazymonkey

I will try that in the morning to see what it shows on the gauge.

Im not sure about the regulator in the IP. The IP was rebuilt last summer.

Thanks!

Crazymonkey

thanks for the tip!

ive been having a hard time trying to find an electric pump that is 15 psi max and in the 60-ish gph or more. I'm still not really sure on that gph number yet

Crazymonkey

this morning hooked the electric pump directly to my fuel pressure gauge and got a 7 psi reading.

its 57 degrees out. Started the engine without electric fuel pump hooked up & fuel pressure gauge reads 4.75 psi.

Installed electric fuel pump again directly before the mechanical pump and with 12v applied to electric pump, engine not running I'm showing 5 psi on my gauge. Started engine and still showing 5 psi on the gauge with electric pump running.

Crazymonkey

Just moved my banjo bolt where the where the fuel pressure gauge is tapped into the fuel system from after the fuel filter to between the fuel filter and mechanical lift pump.

73 degrees out and at this location I'm showing 1 psi

Also with all hooked up as above I installied the electric fuel pump before the mechanical pump with engine not running showing 4.5 psi. As soon as I start the engine it drops to 1 psi
Thanks!

j_martin

I'm at a loss. It's again looking like excessive bypass in the IP. I don't know if you've tried this yet, but at 0-1 psi time, if you restrict the return line and pressure goes up, that implicates the IP.

Crazymonkey

I'm at a loss also

Today I bought a vacuum gauge and t'eed into the fuel line before the mechanical pump.

1st time using one but appeared to be in spec. It was bouncing consistently back & forth at the 2 in. hg vacuum and positive psi. In spec was not to exceed 3.75 in. Hg

Next I removed everything from the mechanical pump to the injection pump. All the metal lines hooked them up to my electric fuel pump and shot diesel through them. All lines flowed freely with no resistance.

Removed the fuel heater and cleaned that with brake cleaner spray can spraying through the turbine looking fins and cleaning it with pipe cleaners. Really didn't look very dirty.

The points where the lines attach to the block (inlet/outlet) of fuel filter, looked clean, shined a flashlight though the threaded holes where the banjo bolts go in and with a mirror could see the light coming through, looked really clean.

as far as I can tell there are no restrictions between the lift pump and the ip.

Put it it all back together.

started the engine and I'm only showing 2 psi with outside temp at 66 degrees

Crazymonkey

Finally decided to take it to a shop,

They said everything was working properly, my problem was in the gauge or the line to my gauge. They suggested to just throw the gauge in the trash & not get another. I told them I swapped out gauges and they said if I really wanted a gauge to use a hard line instead of a fuel line hose.

Thanks for all the suggestions & ideas to help me try to fix it!

KRB

You’ve used two gauges right? And the psi was the same?

I use a grease gun hose, what were you using? Or is it a mechanical gauge?