Plugging Off Fuel Return Line
 

Used to be a way to blow some major smoke , anyone ever tried it on a cummins?

On what year truck? It returns for a reason DM :ph:

yeah, if it dont return or regulate pressure/fuel stuff starts to break

Oh now i know for a "fact" that a Dime will fit right in there then you hook the line back up and now your getting 100% fuel

This was on an old toyota diesel pickup

Tore the clutch out :D but it smoked like a freight train and ran like a bat outta hell

Do they have After market Overflow Valves for the P7100 ?

Doesnt the Over Flow valve regulate the fuel into the return manifold and back to the tank?

i think there may be a FREE mod that were not using to its full potential ?

Even if we dont block it 100% maybe we can restrict it ?

lol I was just being a smart *** ....after all it is you DM ...but that is pretty cool!

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It really regulates right to the tank. And opens lower than the actual pump psi. The return manifold goes back to the fuel filter housing and enters with low pressure fuel.
But , the p7100 seems pretty happy with 25 and opening valve at 22. I know there's some aftermarket ones but not much fuss was made.....the pumps seem to do fine without. Seem's like some of the newer ones are higher than 22

I understand the VP44 is Fuel cooled so that wouldnt be a good idea , But with the P7100 why waste the fuel that the Liftpump is pumping Shove it into the cylinders ?

Just thinking out loud here , Whats your thoughts ? :pca1:

Well....While the P7100 is oiled and oil cooled, the fuel also helps cool the pump , hence the reason it opens lower than pump pressure. Some folks push the pressure way up and modify the overflow to pulling trucks and such. I'm not very smart on this area....someone find hammer! He'll explain better!

Seems like a complete waste of resources to regulate the amount of fuel going into the cylinders with a return line , the technology is there for the lift pump to just send what fuel is needed . the pumps can be cooled by other means :pca1:

Another thing, Whats not used by the injectors is sent back to the filter housing....At some point unused fuel has to go back

not always ;)

The injector has to be cooled and lubed,too. The bypassing diesel lubricates and cools down the injector. Modern VP pumps and injectors have (like the VW Phaeton) an own cooling circuitry with an own diesel-to-coolant heat exchanger, a seperate coolant pump and a additional front mounted cooler. All to make sure heat is out of the diesel.

Actually the amount of fuel that is pumped is way bigger then injected. But it has to be this way to make sure there is always a sufficient amount of fuel under all conditions of driving.
Smoke is not that cool:tttt:. It only shows there is a huge amount of useless fuel which could be burned with more air, resulting in morrre powerrrrr:yeah:

me and a buddy decided to plug off the return line on his pulling truck and we ended up blowing apart a brannew berry grant fuel pump lol