GOT BOOST?

Hey I have been trying to figure out a 0148 code and also my cp3 has been leaking, well I did the high pressure fuel pump and injector return flow test and noticed that there were a lot of large air bubbles in the fuel that was flowing from the cp3 return. I think this is the culprit of my 0148 code, any suggestions on how to track it down. Of note I have my walbro feeding the cp3 at 25 psi. is it possible to have the lift pump sucking hard enough to entrain air along the lines somewhere or possibly entrain it in the fuel tank or is the likely culprit the leaking cp3 entraining air. Thanks guys. Jay

gmctd

Bypassing air bubbles is a prime function of the CP3 internal lift pump, so that is normal - the volume of air sounds not normal, tho

Clamp a short section of clear reinforced 60psi vinyl hose between the walbro and the filter, see how the fuel looks there - be hard to see tho, as air compresses, even at 25psi - do the same between the tank and the walbro, see if it's originating pre-pump - do you have a pressure-regulated bypass?

XLR8R

What's your opinion of a FASS's benefit in view of the CP3/in-tank LP package?

gmctd

The in-tank pump is spec'ed for the 350\600 hi-output package, and will supply up to 500hp - for increased hi-perf duty, an aftermarket solution is required - the Fass pump\filter setup is functional for that, and particularly ideal for those that want or need plug-n-play accessories.

As practical proof of that, place a vacuum guage in the line between the fuel filter cannister and the CP3 inlet - when vacuum starts increasing toward 10"HG, it is time for aftermarket

NOTE - that's also sign that the lift pump is blocked or failing in a stock or modified system

I'm has no intent of debunking the after market systems, Fass or other wise - some of the owner-installations may leave a lot to be desired, tho - what I am trying to accomplish, by posting the rest of the story, is to reassure those stock CRD owners that a hi-dollar aftermarket solution is not required, unless they intend to build for big power

However, I would not recommend a Fass, or any other, to the average driver of a stock truck, when the oem system is purely functional.

The only drawback - the only drawback - is that the oem system is difficult to replace in event of failure, and it cannot be pre-filtered

Is that two? Yep, that's two drawbacks - ok, so I lied - sue me!

84mphcdt

Hi, gmctd, thank you for your various posts around this topic...are you saying that some of us should be hiring out the installation of FASS, etc. systems to mechanics or are you referring to systems that some diy sort of owners have "designed" themselves?

gmctd

Good question - and, as you know, commenting on someone's ability is akin to making disparaging remarks about one or more of their children, and gets similar results - that was not my intent - but, just reading thru the various posts is what prompted me to fill in some missing data

Some installations are just cut\splice, some are more comprehensive, but most all requiring more background information, such as NPSH, which relates to the type of pump and location in the system - whether it is designed for push or draw service - mounted below fuel level or above fuel level, mounted near the tank or near the engine.

Though some consideration should be given as to whether the installer was born with a greasy thumb or not, success is in the details, as in maintaining constant internal diameter of the lines, tubing, and fittings - and don't stick a high pressure gerotor pump up near the engine and hope that casual regulation and bypass return will suffice in a system where the fuel foams easily - stuff like that.

Low-pressure variable volume is required by the CP3 - high-pressure high-volume pumps will cause problems even with intense planning because Diesel fuel foams easily - foamy fuel is aerated fuel - aerated fuel is then compressible, resulting in less fuel volume per actual displacement volume.

So, whether it's a homebrew or homebrew copy of a professional kit or a professional kit, a final test step should be taken - place a section of clear tubing in the line between the pump and the filter, and another in the bypass return line - some bubbles are inevitable, but excessive bubbles in either\both indicate a problem