I was out to the race track and a guy there with a lb7 said to take off the supply pump on the injection pump and drill out the 2 holes that the fuel travels through. He said it would allow more fuel into the injection pump and it would help it from starving for fuel. Has anybody else heard of this? if so does it work? and what size holes? thanks

hmmmm, intresting. I have not. But would like to hear more about this.:)

It is popular with the dodge guys. Go to Relentless Diesels web page and they have the pictures and how to. Just dont modify the fuel pressure regulator.

Here's a link to the thread about it. It's interesting. I emailed him and asked if the same thing would work on a GM pump. I'll let you know what he says. I think there both the same pump. But are they "exactly" the same besides 1 outlet vs. 2?

http://relentlessdiesel.com/forum/viewtopic.php?t=19

It is popular with the dodge guys. Go to Relentless Diesels web page and they have the pictures and how to. Just dont modify the fuel pressure regulator.

Why would you say not to modify the regulator?

You could also get a lift pump to help it from starving if you dont have one..

it works on GM

Very nice writeup

The valve inside the regulators are different, I am not sure the mod would work on the duramax. The dodge valve is a triangle shape, at idle the valve is in the closed position getting fuel from the top of the triangle and the duramax valve is rectangular and wider than the bottom of the triangle on the dodge. So I dont think making the slot wider is going to do anything for the duramax. Just my opinion.

Lift pumps would help as well but the more free flowing things are.....Just gathering info for anyone interested. This is the first I've seen of someone showing how to modify the CP3. Pretty interesting!
Pineywoodtom... Thanks for the info. I guess maybe this is a dead end..

I dont know if the regualtor mod will work or not, but i know the pickup pump mod is the same on a GM

Do this mod to the supply pump and regulator to help with holding rail pressure. I hear it can help around 2,000 psi on rail pressure when running a big tune.

Randyu

Ya don't think about it, do it, do it. Just make sure you've got an entire day to devote to it!

Oh ya be EXTREMELY careful when modding the regulator! Only cut the very bottom! If cut too high up it will buck. Your rail pressure might get a little eratic.

You'll like what is included in the FPE Regulator kits.. It pertains to the gear pump.

You'll like what is included in the FPE Regulator kits.. It pertains to the gear pump.

You tease. Tell us more...

Don't have a picture of it yet so I won't go into much detail.. It solves the issues with the pump, that's for sure.

So people have done this mod with the regulator and the gear pump and it worked.... Someone said the regulators internally are shaped differen't and some say it will work....:help2:
Brayden.... Stop with skimpy detail and tell us more! Price, when it's available...what! Your killing us here!!:clap:

If anyone is interested here's the response I got back from Chris @ Relentless Diesel....

""The FCA's are slightly different on the duramax's.
The benefit from doing the fca mod is minimal at best.

As you may know the FCA is quite a bit harder to get to on the duramax
as
compared to the Dodge. If I were you I wouldn't waste my time.

My personal advice would be to save up for dual cp3's. Don't waste
much
time or effort trying to modify a single one. As soon as we started
installing dual cp3's on the dodges it was such a dramatic improvement
I
felt like I had wasted my time with all the efforts to push more from a

single.

-Chris

With the cost of putting duals on granite they have come down, I would give a try for myself just to see if there is any benefit.

For the effort I've put into the mod'd FCA, I think it has been well worth it. Seat of pants and in the rail pressure logs that I've done.