Fuel pressure

[WillWagner]

I did a service on the beast today, oil and filoters, fuel filters. Just for S&G, I put a QD fitting at the bleed fitting in the sec/final filter head. I got 30 PSI at idle and 63 at high idle! Is this normal?? How do you get more positive pressure form an in tank pump that isn't engine driven?

 

[cranetruck]

Sounds normal Will, the in-tank pump puts out about 5 to 7 psi and this is boosted by the pump on the IP to 30 to 60 psi before feeding the secondary and final filters (and the flame heater pump too).

 

[JDToumanian]

I believe that is correct... The in-tank pump only puts out something like ~3-5 psi, fuel passes through the primary filter and then into the injector pump where a small gear-driven pump steps up the pressure to ~50 something psi (I'm doing this from my memory, which isn't really worth a crap)... Then it goes through the secondary and final filters and into the FDC and on to the hydraulic head. If you want to check the pressure coming from your in-tank pump, you've got to tap in closer to the fuel tank...

Jon

 

[gringeltaube]

How do you get more positive pressure form an in tank pump that isn't engine driven?

Not the in-tank pump but the small booster pump at the IP is engine driven. At 60 psi the relief valve on top of the secondary filter is open and most fuel is returning to the tank.

 

[WillWagner]

RE: Re: Fuel pressure

Guess I need to look at the TM' t see how it flows! I was expecting 8-10 PSI max. Thanks guys. I had a 30-60 compound gauge hooked to it, thought I was gonna ruin my gauge!

 

[houdel]

RE: Re: Fuel pressure

The data is given in the LDS465 manual in the TA section, but as memory serves me the pressures you mentioned are right in the ballpark.