Looking for a mild bomb to increase low to mid range power with in-cab adjustability and low risk of EGT/boost problems, I opted for the VA C3.1. And it does exactly what the vendor told me it would do, and caused no issues with the EGTs or boost. However, about 1 hour run time after the install, my rig started missing/stumbling like fuel was being cut back intermittently, kinda like the stumble that happens on a gasser when the fuel pump starts to go south.
Thinking that the ECM may need time to "learn" the changes, I left the box on, toned back my throttle foot, and after another hour of 70-75 mph driving, the problem went from intermittent to frequent. Trouble code P0088 (High Fuel Rail Pressure) was set, and the MIL lit up. Turned the box off, after 5 or so starts, the mil went out. Had the code erased w/ a Snap-On scanner, called vendor, was told he had never seen this out of the VA C3.1. He quickly sent me another box to try, hooked it up, same story.
Obviously now the issue is not the box, but my truck. I left the code set (MIL has turned off), removed the box, and am headed to the dealer Monday AM to have the rail, pressure relief valve, et al checked. I'm thinking perhaps an injector or rail/sensor issue - any other ideas or directions I should steer the dealer towards?
Besides pouting because my toys don't work right, I'm concerned that the techs won't be able to find a problem, as the truck runs like a top without the box - but that this can be an early indicator of a forthcoming injector/pressure/pump failure that's gonna leave me stranded and thoroughly PO'd. Appreciate any help or insight offered.
Sorry for the long post - just trying to give all pertinent facts.

 

Wow my box has been trouble free for about 10k miles! No issues at all with the confuser. I got the dreaded CP3 pump leak, but I must add this is not at all related to the box.

 

I'm pretty sure it's the truck and not the box, since I tried two, and haven't found anyone that ever had problems with the C3.1 program. Just trying to figure out how to get the service dept to see the problem without having the box hooked up - all that remains of the problem is the code. Hoping they'll do some actual troubleshooting to test the fuel system.....

 

Sounds like the high pressure relieve valve in the CP3 pump failed. This issue also has been seen with the EZ pressure box.

MikeyB

 

Is this something that can be found and fixed without the box running on the truck, since it runs fine without the box? Or perhaps I can purchase the part and do the fix myself? Not sure if the CP3 pressure valve is the same as the rail pressure valve, I know I can't buy that one - dealer repair only, from what I've heard.