ULSD 101

[lostcause]

Gasoline engines work the same way - but with a single, on demand pump that ramps up as the engine needs it.

i guess i never really thought about it being able to work that way. i assumed it would have to keep a reservoir available but i guess with the number of sensors providing feedback on a vehicle now you can probably meter and adjust fuel on the fly pretty easily. i'm not sure when they did away with the replaceable filter on the gas engines, but i'm thinking it was 04 or 05.

i also have an 01 gm with a diesel, and i admit i never gave a thought about the pressure and temperature difference between diesel and gas until you mentioned it. that truck only has the injector pump supplying the system and i guess there isn't much alternative to returning a lot of fuel with that system. i do have an electric lift pump, but all it does is move fuel from the rear tank to the front tank to keep them at an equal level. the fuel system only draws from the front tank.

i guess it should have been obvious about the heat issue, since that truck has a "fuel cooler" on it. the first time i heard that term tossed around i thought it sounded like the equivalent of muffler bearings, but no, it actually has a little radiator in front of the fuel tank to help cool the fuel. from the best i can tell the fuel is actually used as a coolant for the fuel injection electronics module too. tracing the lines, they appear to go right through it.

 

[Foxtrot08]

It's why they keep fuel pumps submerged now - especially in gas engines. It keeps everything cooler and in theory, with less heat = longer it should last.

With the primary fuel pump in a gasoline engine submerged, there is no reason for a secondary pump to feed a second reservoir - in my opinion.

Why they do it with a diesel? Probably to prevent cavitation of the tank when it suddenly ramps up from idle to 3000 RPM and so much fuel flowing.

I've never really spent much time messing with gas engines... I've been into performance diesels now for a bit. For those diesel guys, here is my ride:

2008 F250 4x4 Off road, King Ranch edition. Spartan Tuner, 4 inch pro~flo DPF/CAT delete, S&B Stage II airbox, Rudy's diesel IC pipe, Banks Engineering IC, Diesel site boots.

 

[jonyyuma]

Foxtrot, Did none of your trucks ever have a Racor fuel filter added to them. They have superior fuel element, that will not pass water? I know i was amazed at the amount of water that I caught in my PU fuel system, and i was not doing a lot of miles a year? I did use PS..

 

[jonyyuma]

Lost cause, The Gen-station has so much diesel slobber or fuel return back to the main fuel tank..20,000 gal.us..The temp of the fuel came up to a unsafe level in our hot summers...We added a 5 ton chiller to cool the fuel, before it returns to the fuel tank, , of course it has temp probe on the line?? Of course the engines are huge at 1200hp each....so less for the smaller type engines..Glad to hear GM has improved their systems for diesels?

 

[Foxtrot08]

Foxtrot, Did none of your trucks ever have a Racor fuel filter added to them. They have superior fuel element, that will not pass water? I know i was amazed at the amount of water that I caught in my PU fuel system, and i was not doing a lot of miles a year? I did use PS..

Ironically, I just had to look into a Racor fuel filter because my sister's boat has one.

Her boat is also powered by a 26? HP 'Universal' diesel, aka Kubota. Which is the same engine in the BX2660 lol.

Yeah I've seen them... we haven't installed any yet on our fleets. We used all hygroscopic filters on our fuel pumps to catch water coming out of the tanks.

 

[jonyyuma]

Okay, at least you have noticed them..They used both types here...I prefer the Racor, I have a small one to go on my Kubota to protect the engine better than just the stock 15 trying to locate it is another puzzel....I am reluctant to go to the 2 element..

 

[Foxtrot08]

Yeah I had a really hard time matching the filter to anything. The only place I was able to order one was on the internet.

 

[TWD]

Wow, lot of great info in here thanks :thumbsup: