IT'S DRIVING ME CRAZY!!!!! Need to start the troubleshooting SOON. Coming home from work yesterday the RP was jumping from 10k to 15k at cruise and the engine had a noticeable surge with the jump. Will definitely verify full RP reading with FCA unplugged in the morning. Other than that, the guage IS good and I guess the spring in the relief valve is bypassing.

 

Sooo........days later.....I finally got around to unplugging the FCA....RP gauge went straight to 26k psi without hesitation and stayed there without fluctuating. Could that still mean that the PRV is not holding properly at highway speed? I'm not against capping the PRV and running it that way to see what happens.....I'm not in any way taxing the system on pressure. At WOT the system does good to reach 20K psi.

Any thoughts.....could I possibly be looking at a fresh CP3 in the near future?

 

Well the relief valve is elimimated as a culprit. If it holds 26k in the driveway it'll hold 12-15k on the highway.

The cp3 is another story... so maybe/maybe not. It's one thing for 26k in the driveway, another for 15k on the highway when you are now asking for a lot more volume.

What kind of programmer are you running? It is not necessarily that uncommon for programming to create those symtoms. Especially the come and go kind.

Is it possible to get a dealer flash and drive around a little? Or if it is a box, disconnect it? Try a different FCA? You can plug the PRV for now to ensure that is not part of the issue too.

I still have a gut feeling this is electrical and not mechanical at this point.

 

Need to watch to see what is commanded vs. actual RP.

Tobin

 

I'm running the old, original Bully Dog Power Pup downloader. It stays on the tow program 98% of the time. I've actually spoken with some of their reps at truck shows and they tell me that there are no updates of any kind for that downloader being as it's "old".

I do have a spare FCA and NEED to try it out and see if that's an issue but with the current one supposedly working correctly....i.e. I don't have any idle issues and it fires right up. I'll try and find time this week to put it in.

Thanks for your input soulezoo!!!

 

Finally got around to swapping in the new FCA and the pressures settled down some but the fluctuation at highway speeds is still present. The surge isn't quite as noticeable either. If switching back to stock programming doesn't solve the issue does that only leave the CP3 as the culprit?

On a side note, while at highway speed, I can go WOT and the RP gauge will drop a few thousand psi (about 3-5k) and take a second or two to start climbing. Even then I can barely hit 20k psi at full throttle. Is that normal with stock CP3 and 100hp sticks with my programming?

 

yes it is normal, 100hp sticks is awfully large for a stock cp3... it is struggling to keep up. If you had a smarty, you would be draining the rail. Hitting 20k with the setup seems normal as well.

Sounds more like the cp3 is not necessarily "worn out" but simply "out of capacity" or on the edge of it.

Is the FCA modified? That can help some.

 

Everything on the CP3 is stock.......with tons of miles and hours on it. Have seriously been wanting to do the pump mods with Motorsport Diesel parts. Would that help out at all? With the AirDog pushing the extra fuel I don't see how it could hurt!