Fuel Pressures

What are the flow/press. specs for the M35 primary fuel pump?
Flow: G/S (gph)? Pressure: kpa (psi)? I would think low flow, low pressure.
Do any of you guys run a fuel pressure gage? I'm thinking about adding one to mine in order to help monitor the intank pump condition.
I think Saturn carries a fuel pressure gage. Thanks.

A fuel pressure gauge would be good for monitoring the fuel filters too. A build-up in the pressure would indicate that the filters may need changing.

I have been playing with one pump for the new heated tank that soon will be on the deuce. It pumps about 4 gallons/minut open ended. I used it to empty the tank a couple of times. In the system the rate and pressue will be different.

________________
Bjorn
MVPA 19212

1968 M49A2C modified. 1972 HIAB 765A crane and 1960 M756 pipeline truck bed.
11.00-20 NDCC singles.
M103A3 trailer.

"Some things cannot be made better, just differently"

CURRENTLY WORKING ON:
Adding small fuel tank (starting and shutting down in cold weather) and installing heating coil in main tank for biodiesel/cooking oil.

Fuel pressures from the LDS-465-1 troubleshooting manual:
700-750 rpm, 30-35 psi
1200 rpm, 48-57 psi
1600 rpm, 57-64 psi
2000 rpm, 63-69 psi
2400 rpm, 65-73 psi
2600 rpm, 65-75 psi
2850-2900 rpm (max no load speed) 65-75 psi
They show a 0-100 psi gauge plumbed onto the top of the final fuel filter.
These pressure ratings are for any approved fuel.
The in tank pump should give around 7 psi.
Hope this helps.

As flow increases, pressure drops. How are the high pressures developed prior to the injection pump from a 7 psi lift pump?

There is a second pump on the IP, lower portion, it feeds the secondary and final fuel filters and the flame heater system also.

Bjorn

Ahhhhhh..... I thought that fuel entered into the IP after the secondary fuel filters.
So in order to monitor the lift (intank) pump, the pressure gage would have to be before the primary filter, (or after the primary fuel filter to monitor the primary filter restriction). This would be low pressure readings.
Now, to monitor the secondary fuel filters, the gage would be after them, but with a much higher pressure reading.

the gage should be AFTER the filters, this gives the working pressure to the engine, if it goes down a bit at a time its the filters, all at once its the pump

Or put in a differential pressure gage that has a line pre-filter and one post-filter. then you know exactly how much flow is being restricted.