johnnyboatman

iTrader: (5)

filter was changed after it went into limp mode, then we reset the computer and test drove it. the fuel pressure will drop way down when the rpms started getting high. so i think it needs something to help feed the fuel, Is there a easy to install external fuel pump for these? its a 06 with a 6speed auto trans.

kidturbo

Two most likely causes for the fuel pressure drops at high RPM:

1. Rubber fuel line section is collapsing, check for service bulletins about them. Will cause limp mode like a clogged filter. Diagnose with a vacuum gauge on the test port between filter and CP3 pump. Should not exceed 4hg at idle or like 10hg WOT. Please verify my numbers before testing, but HERE is a link to a post about checking it... The problem will get worse if it's a kinked line, while a lift pump will eliminate such issues going fwd.
Lift Pump I Run

2. Returning to much fuel. Typically from the pressure release valve on the high pressure fuel rail popping open. Normally won't cause it to limp mode, but is a common issue with higher HP tunes. Cheap easy fix. Ten minute job to replace with a Race Fuel Valve or you can just do a shim trick on the stock one. HERE is a quick video showing how to change it.

That's the easy / cheap fixes. If it's neither of those problems, possibly an injector or pump returning to much fuel, but not as likely.

Unlimited jd

iTrader: (5)

If it has over 120k on it you prob need a cp3 pump. Not saying you won't find what kidturbo posted, but in addition to. I have yet to see one over that hold rail pressure. I know guys that replace them every season just to stay fresh.

s022mag

Some good points that I probably should of brought up with Kyle, but didn't. I believe his tunes eliminated the EGR all together, didn't put a block off plate in though.

I got the dsp5 1)stock 2) light tow 3) heavy tow with turbo brake 4) fuel mileage 5) low hot tune 75hp

I don't plan on taking the truck over 93mph, but if I do then I'll call him back to see if his tunes eliminated that, good point on the tire pressure gauge but I think I'm OK there, I put some 420S on last summer and no light came on.

Thanks for the help guys, I think a lift pump is definitely in my future.

ChargeIt

A tune does not eliminate the EGR it just instructs the vane to remain closed as much as possible. From my understanding, it will still open under certain conditions.
Blocker plate does block the valve but if not done well, can leak. It can also be a real PIA to get in place. I have mine programmed closed as well and have not had a need to inspect how well it is working but I assume mostly closed is better than open?

The 93mph is not a huge deal. If you have 75mph interstates and run with the flow to 85, 93 is not that much more if you are trying to speed up to hit a gap or pass.
Funniest was when, I got into a little testosterone battle on a two lane and I assume he had a tune but maybe not, he was messing with me as I tried to pass. I could tell exactly when he hit 93 and defueled as I drove around him. Look on his face was priceless

Actually, I find myself cruising along slower most of the time in the truck vs a car.

ChargeIt

I agree with kidturbo and would try a lift pump first. CP3 is likely getting weak but lift pump may help it survive much longer. Especially if you have weak fuel lines, pump can solve both problems for 1/4 the cost. If you still limp, lift pump was a great addition regardless.
Air Dog and FASS both have mounting brackets that easily bolt up, I don't know on the individual PPE and Kennedy pumps but assume they should be easy to mount.
I don't think installation is very hard but the proper fuel fitting pliers make the job much easier. I paid to have it installed. Those that do them regularly can knock it out pretty fast, know where to tap wires and make it a smooth install.

I am a DIY guy but my theory is, if I will only ever do it once, let someone else do it, especially if special tools or knowledge make the job much easier. If it is something repeatable like brakes, flushing or boat impeller example, DIY will pay bigger dividends.

Unlimited jd

iTrader: (5)

Do not buy a Kennedy or ppe pump. I had at least 6 Kennedy pumps fail. And got told pound sand. The ppe pump is a rebranded edelbrock. I ran a Mallory comp 140 for a few years on mine. Made my own 10/2 micron filter and water separator system. Worked fine to 850 hp

kidturbo

Might have to disagree with ya on the fuel pumps Lil Red...

While Mallory builds the most respected gasoline race units, I actually run the 160gph Edelbrock model 1792 with an internal pressure regulator / bypass. Which as Red stated is the same unit PPE sells. "There goes my discount.." That PPE pump listed above is the smaller 120gph unit set at 6psi without a regulator. Either way, these are all re-branded from "SX performance", the true OEM who does make reliable fuel system parts. I've logged 4 years with mine feeding a 650hp Dmax in the boat, running mostly 80% biodiesel, a higher viscosity fuel. So it's got good motor windings at least..

As for pump problems, they're all rotary vane designs, same as FASS and other high $$$ units. Mine had a very fine screen on the inlet port which gave me some troubles in the boat due to some junk in the fuel tank. I finally got pissed and scrapped that screen, it's been fine for two years now. Easy to work on also, only 3 bolts to disassemble. Nice thing is, if these rotary vane styles fail the factory lift pump will still pull fuel thru the electric lift. I've tested this multiple times by accidentally leaving mine switched off. Just know there is several good options out there for under $300, so shop around and read reviews on each.

ChargeIt; your correct about that EGR block off plate. The EGR valve will easily blow open above 22psi boost without power to the valve to holding it shut. Acts like a faulty MAF or sticky VGT. About an hour to slide a $2 piece of steel in there and that problem is gone, along with that risk of melting the cooler down. Easy DIY job for a Sunday afternoon.