** Help. **

[Nemo]

Doing some research for a friend, below is what he is telling me...

His truck is poping fuel codes, cannot view code with qaudzilla or PPE Programmers and doesnt pop on the Dash. Full scan with efi shows the code, low rail preasure at part throttle, little over 1,000 RPM it starts to have low rail preassure.

He replaced ecu 6 months ago to try and fix the problem with no luck. He has spent countless time and money and can't find the problem.

No matter what programmer is in it, it does the same thing.

Someone had mentioned to him that if he "puts the new EFI software in his truck" that it will most likly fix the problem... I am not 100% sure what the kid was talking about so if you can elaborate for me that would be great..

He has a PPE fuel pump so it is getting more than enough fuel and he runs his Quadzilla on a lower level as well...

[GMC-2002-Dmax]

Injectors ??

Possibly it has high return rates or a bad FRPCV on the CP3 or a bad CP3 pump.

[Nemo]

Injectors are fine, if it were the CP3 it would be messed up the whole time... It is fine off the line, poors smoke like any other would but at a certain point it just drains the rail, even at 30-50% throttle. He checked all the lines etc and nothing is cloged... This has been happening for a little over a year and no one can figure out what it is.

[GMPX]

Someone had mentioned to him that if he "puts the new EFI software in his truck" that it will most likly fix the problem... I am not 100% sure what the kid was talking about so if you can elaborate for me that would be great..

Sorry, not sure what that is referring to.

[Nemo]

Hmmm, well, anyone got any ideas?

[ynotracing2221]

I would think bad cp3. Sounds like the CP3 is starting to go out, thats why it can't keep pressure up when it needs a lot. Just my .02 tho.

[MMLMM]

Is the FPRV shimmed?
If so, how much?

[GMC-2002-Dmax]

Injectors are fine, if it were the CP3 it would be messed up the whole time... It is fine off the line, poors smoke like any other would but at a certain point it just drains the rail, even at 30-50% throttle. He checked all the lines etc and nothing is cloged... This has been happening for a little over a year and no one can figure out what it is.

Sounds to me like a fuel restriction, bypass the stock fuel filter for a quick diagnostic run, also does the truck have lift pumps ???

[McRat]

Yeah, step one would be to install a fuel supply gauge. Get an El Cheapo boost gauge from Summit (or any other low pressure gauge, be nice to have negative and positive) and install it right before the CP3 inlet.

What EFILive can do is help diagnose the issue, and it can disable "limp modes". It's not going to fix hard-parts issues since it doesn't weigh enough to use as a hammer.

[Big D]

any updates on this nemo?