Hello
A fella I work with bought gauges for his truck a 03 HO with the 6 speed. He tapped into the fuel line coming from the bottom of the fuel filter running to the high PSI pump is. ( I think that is what it is) It goes to where the injection pump is suppose to be.
He is seeing 7 psi at an idle and and sees the psi drop a few psi when rowing through the gears, but with his Bully Dog Torque Dog box sent at the high output setting it drops to 0 . I told him that is'nt a good thing and if it was my truck I would try and keep at least 2 or 3 psi. I am thinking old school where the fuel COOLed, CLEANed, LUBEd and of course made the engine run.
I have my own interest in this for my wife's truck which I recently added a edge EZ box. I have not installed a fuel psi gauge to her truck yet, I will be ordering one this week.
Question
1 What is the safe fuel psi for this engine?
2 What are you doing to supply more fuel pressure?
3 Where did you tap into the fuel system to get your readings?

Thanks for your help. The new trucks are a bit different than the old stuff.
Trying to learn as much as I can about the 3rd Gens.
See Ya
Chris

 

Hey Chris, Johnner has been through this and found the limits of the system. He has a Holley Blue with -6an stainless and aeroquip fittings on his 04. Send him a PM (Banshee) to see where he tapped for the gauge.

 

I'm experimenting now with using the boost channel of the SPA technique gague to read fuel pressure. I put six feet of 1/4" fuel hose on the sender, and connected to the CP3 low side point using a tapped banjo. bingo, have a $15 fuel pressure gauge. We'll see if the electronic sender itself can tolerate the abuse...

I see 8 lbs at idle, and all of the aggressive pressure boxes (Quadzilla, Bullydog, Banks, Volumizer, Predator 3) pull it down to 0 or 1 psi. thats what you get for raising rail pressure to 26,000-27,000 psi. the low side can't keep up with the flow requirements.

Moderate fueling boxes like the EZ and VA maintain a higher pressure on full load. But the EZ, at 70HP, still gets close to zero.

 

Doug, did you test the VA CP3.2?

 

not yet! soon to come though. In general I expect a pretty good correlation between low-side fuel pressure drop and the gain in horsepower output. Its just fuel in fuel out, whether you accomplish the additional fueling via pressure or duration. I just haven't measured peak horsepower yet on these boxes so I don't know how creatively they have been reported. I'm just thinking here that a "100HP box" (depending on what that means) will drop pressure to near zero.

I'd like to see more of Banshee's work on this. From talking to Rod@Wildcat, I have particular interest in the Holly blue because of its lower peak pressure output (appears to be better regulated)

 

I will do a pusher of some sorts soon as well!

 

That is a good place to get the fuel pressure readings from, after the filter and before the pump. 7psi is pretty normal and it will drop with fuel demand.

 

Thanks, CMNSPWR
I will talk to Johner and see what he done with his truck.
Thanks for the information.
See Ya
Chris