Return rate quantity

[Dallas S]

Lmm, brand new cp3, ppe race valve(tested, does not return any fuel), injectors replaced twice with used ones.... At idle pressure follows right with commanded. Go for drive at hits 100mpa and then starts falling. This is with factory supply line or out of a Jerry can strait to cp3(bypass filter ect)

I want to run the truck off a Jerry can and run return into another bottle. Want to compare fuel used to fuel returned but I don't know what the factory spec is... Any help?

 

[Dallas S]

Should also state that a local shop is the ones that have done all the work. Two used cp3 then went to a new one, and the injectors were apparently tested, one new one was installed. Race valve return is also hear say. Hard to go off hearsay that's why I'd like to simply see how much fuel it uses and returns before I start going over others work.

 

[Dallas S]

Any ideas guys?

8 new injectors, new cp3, new drivers rail(race valve chewed original), ppe race valve.

Can build psi fine at idle(up to 160). Race valve leaks no fuel at any psi(at idle). As soon as load on motor actual psi drops fast. Very little power. Lmm with dpf delete. Was a ppe tune, now just a stock tune with dpf turned off.

I had some time to look at the truck yesterday. I tested race valve return, and returns from injectors(2-3 ML/15sec crank) and reflashed ECM just to make sure and it needed speedo recalibrated anyways. Balance rates and return rates looked good(+/-2 at 9mm3 calculated rate). All I had time to do. They went ahead and put all new injectors in anyways today cause they are at a loss. Exact same result. Next chance I get I'm going to double check cp3 supply and return lines and routing... I really have no idea at this moment

 

[SSchmi5519]

There should be nothing getting past the race valve.


Sent from my iPhone.

 

[Dallas S]

Ya, nothing is. I figured psi is psi so instead of drivin the truck with a bottle on it I supply commanded psi and watched the return. No fuel passed.

 

[chevyburnout1]

I'm kind of confused on your first post. Did you road test it with the fuel supply straight out of an alternate fuel source? Sounds like most of the high pressure circuits have been checked, so more than likely a supply side issue. Can the shop check supply line vacuum? When actual fuel pressure drops is desired still up where it should be?

 

[Dallas S]

Sorry, road tested with a line from cp3 to Jerry can. Same drop in psi. At idle command and actual follow as usual, road test actual drops from command. Usually desired and actual will follow right till ~80mpa, then desired will keep climbing as usual, and actual will fall to 25-30mpa

5 months ago when this started the truck would smoke like crazy when psi dropped. Now it won't even haze. No change from reflash.

*edit: when I say I ran a line strait to the cp3 I should mention it was actually from the 1/2" fitting behind alternator, where test port is. And while typing i just realized maybe that test port is leaking air...

 

[demax990]

it really sounds like a fuel filter or a supply line to the cp3