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Discussion Starter #81
Yeah, just don't run the truck long like that. If the PRV is bad you'll see the pressure bounce.
The truck made 26 dropped to 18 then held the 26 for a while, does this mean that my prv and the cp3 are okay and it’s possibly my lift pump that slowed down, I heard it skip and that’s when it dropped
 

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I would think that if the cp3 was bad you wouldn’t make the 26,000 or it wouldn’t hold, or the prv wouldn’t blow off as well. If The truck makes 26000 steady wouldn’t that mean that there isn’t a fuel issue because it holds 26 steady?
There can definitely be a fuel issue. Because you aren’t applying any load at that time.
 

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Discussion Starter #83
There can definitely be a fuel issue. Because you aren’t applying any load at that time.
So where would you recommend I go from here, put a gauge on the fass and see what it puts out? if that puts out the pressure it’s gotta be my cp3 then?
 

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Haven't seen that before, myself I would probably pull the bolt, confirm it has a PRV, then plug the return line (it will flow from the CP3/Injector return otherwise) and put a hose on the PRV and confirm it actually pops. I did this once without the hose...don't recommend it. Diesel fuel fountain. Anytime I've tested a good PRV, they fire right up to 26.1K and sit solid, but when I had a bad one it bounced.

Need to track down what caused the drop. Specially if you can do it again and it does the same thing.

It shows it can make pressure, but doesn't mean it can keep up with the volume demands that are needed while driving. That can be a handful of things. Bad lift pump output, cascade valve issue, FCA issue, CP3 itself issue.
 

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Discussion Starter #85
Haven't seen that before, myself I would probably pull the bolt, confirm it has a PRV, then plug the return line (it will flow from the CP3/Injector return otherwise) and put a hose on the PRV and confirm it actually pops. I did this once without the hose...don't recommend it. Diesel fuel fountain. Anytime I've tested a good PRV, they fire right up to 26.1K and sit solid, but when I had a bad one it bounced.

Need to track down what caused the drop. Specially if you can do it again and it does the same thing.

It shows it can make pressure, but doesn't mean it can keep up with the volume demands that are needed while driving. That can be a handful of things. Bad lift pump output, cascade valve issue, FCA issue, CP3 itself issue.
I’ll obviously pull the bolt, my shop has a rig to test the out put from the fass,
If the fass makes proper pressure I’d assume it’s gotta be the cp3 correct?
It proves that it can hold the pressure at the 26.1 with the prv
 

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I’ll obviously pull the bolt, my shop has a rig to test the out put from the fass,
If the fass makes proper pressure I’d assume it’s gotta be the cp3 correct?
It proves that it can hold the pressure at the 26.1 with the prv
Should get a fuel gauge on to see what pressure your getting while on the throttle. You already know you are getting below demanded rail.

If it were me I would want gauges to watch lp and rail pressure.
 

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Discussion Starter #87
Should get a fuel gauge on to see what pressure your getting while on the throttle. You already know you are getting below demanded rail.

If it were me I would want gauges to watch lp and rail pressure.
Yeah I’ll probably get one after this, the shop is going to pull the fuel pressure off the fass and we obviously have the numbers off the rail pressure. I would say if the fass puts good pressure out, then it’s the cp3 the prv holds the 26.
if the fass does not put the pressure out it’s the fass then.At least that’s what I’m thinking
 

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I’ll obviously pull the bolt, my shop has a rig to test the out put from the fass,
If the fass makes proper pressure I’d assume it’s gotta be the cp3 correct?
It proves that it can hold the pressure at the 26.1 with the prv
The only other thing that can affect rail pressure is the crossover tubes not sealing to the injectors well.
 

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Discussion Starter #90
quick thing here from looking at some logs of half throttle, the desired and acutal pressure are only off when your at full throttle, or when i floor it, could my lift pump not be big enough to feed the cp3?
 

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Discussion Starter #91
as well it only has the pressure difference or drop on some logs, on my other logs it looks good, it seemes to be an on and off issue
 

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Discussion Starter #94
Shop says everything checks out and that we have good pressures, I was mistaken as it is a stock cp3 and is pushing proper pressures, I’ve asked mat to adjust
 

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well hopefully that was the issue. Would have sucked to switch tuners and run into the same issue. Though I'm kind of surprised that wouldn't have been caught from the logs.
 

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Discussion Starter #96
well hopefully that was the issue. Would have sucked to switch tuners and run into the same issue. Though I'm kind of surprised that wouldn't have been caught from the logs.
Still kinda annoyed me that it took 3 weeks and 42 emails for him to look at the rail pressure
 

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Still kinda annoyed me that it took 3 weeks and 42 emails for him to look at the rail pressure
I think somethings happened with him. I have my own complaint, but trying to give him a chance to fix it before I blast him. Tunes fine, it's a separate issue. He doesn't seem like the same person I talked to in March/April.
 

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Discussion Starter #98
I think somethings happened with him. I have my own complaint, but trying to give him a chance to fix it before I blast him. Tunes fine, it's a separate issue. He doesn't seem like the same person I talked to in March/April.
Yeah I don’t really know, it seems that everyone liked him but he’s gone down hill from what I’ve heard, I hope he makes the adjustments and I can give him a positive review but we will have to see.
i completely under stand if he’s got personal thing going on too
 

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I would bet since the epa has turned the screws down south, and the fact his name is getting around more, he’s probably swamp with questions. Not that it’s an excuse. But maybe he needs to manage better. He prob never saw his tuning being as popular as it is.
 

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Discussion Starter #100
I would bet since the epa has turned the screws down south, and the fact his name is getting around more, he’s probably swamp with questions. Not that it’s an excuse. But maybe he needs to manage better. He prob never saw his tuning being as popular as it is.
Yeah man I don’t really know.
I had a fucking city cop write me a ticket for “excessive smoke” douche bag....
Any ways hopefully he can get it dialed
 
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