Not holding rail pressure help. x2CP3

[slipclutchms]

I am running an airdog 165 with pressure gauge, 15 psi low side runs down to 10 psi truck hot at wide open throttle. I just installed a dual fueler kit from PPE. I TIG welded the FPRV banjo bolt closed at the same time. I command 26k and I will see it for a split second before dropping to 18k. If I unplug the regulator from the second pump there is no change in rail pressure. I swapped regulators thinking that it was stuck but no luck. At this point it has to be the second CP3 is bad...(possible as it was a used pump) or the injector return rates are to high. Correct? If I use the DVT and command 160 mpa it holds it fine nice and steady. What is the easiest way to isolate the problem here? Also because I was curious I plugged in another regulator into the second cp3 position and held it in my hand while someone turned the key on just to see if the pintle moved or clicked or anything. Nothing happend...Is there a way to make absolutely positive that the black box is working? Thanks guys I am scratching my head on this one

 

[SmokeShow]

Didn't someone recently mention having some return & feed lines swapped & resulted in similar situation? Have you triple checked that everything is routed 100% correctly?

If not, it seems the second cp3 is tits up since it won't go to 26k even with fprv unplugged. I could be way off though?

 

[slipclutchms]

Ah yes of course.....So I removed the feed line and verified I have flow with the key on from the lift pump....the feed is going to the nipple which is parallel with the ground. I.E. the return is connected to the nipple next to the high pressure output. This is correct right????

 

[xcablb7]

that's how mine is

 

[slipclutchms]

james if you yank the plug off the regulator on your second pump it brings it to full pressure right?

 

[skintback]

Sounds like the box isn't working bad ground or power i would start there and get the meter out make sure your getting power to the reg

 

[05smoker]

Sounds like the box isn't working bad ground or power i would start there and get the meter out make sure your getting power to the reg

If it was a bad ground or no power, they would be wide open. Been there, done that. Doubt it's the second CP3. One good one should hold better than that. I'm thinking injector issues (possibly cracked bodies). How old are they?

 

[slipclutchms]

When the regulator is NOT powered it should be at max rail right?! What should I have for voltage at the regulator at idle?

 

[ChevyDieselLLY]

X2 on power to the box.

 

[05smoker]

When the regulator is NOT powered it should be at max rail right?! What should I have for voltage at the regulator at idle?

Yes, if you unplug the regulator it goes wide open.

 

[KB3MMX]

Could be a bad splitter harness for the dual cp3 pumps, not uncommon.

Sent from my SCH-I510 using Tapatalk

 

[05smoker]

When we had issues with the dual pumps, we unhooked the second pump completely to rule out the controller. Start with that IMO.

There have been issues with the controllers as some of the other guys are saying.

 

[slipclutchms]

I did unhook the regulator completely........no change. And I do have power to the box with key on. I also have tried pulling the fuse to the box and no change either....How can I make sure the box is good?

 

[1lowdiesel]

Try calling Dan at PPE. He was very helpful when i ran into an issue with one i did a few years back, he can tell you how to test it.

 

[xcablb7]

what happens if you unplug both regulators ?, it should go full pressure when you unplug the regulator, if you lok at b1010 reg current goes down as flow goes up, no current=max flow. so i would think you have a high press leak somewhere can you send me a log ?

 

[slipclutchms]

I just got home and checked voltage at the second CP3 reg. and got around 9 volts. Sound right? James I will send you a log. I did talk to Dan yesterday and he seems to be thinking that the injectors are returning to much fuel. The injectors are about 1 year old and have maybe 10k miles on them. Balance rates are perfect and the truck runs perfect other than this issue. No fuel in oil etc. If it was a high pressure leak it would be rather apparent wouldn't it? See it in the oil or outside of engine? and again using the DVT and commanding 160 mpa it holds that perfect at idle....I just want to exhaust all options before doing injector(s)

Thanks guys

 

[xcablb7]

i would think so, unless it's an injector leaking into it's return i.e. high return rate or the cp3 returning too much not that i've ever seen that but thinking more in theory a leak from high press to the return

 

[S Phinney]

A really easy way to get a quick idea of return would be to disconnect the return at the tank and see what comes out. It isn't that hard to do a bottle test for return at the engine either.

 

[slipclutchms]

The return will be high anyways because of the x2 CP3 right? At least that would make sense to me. I tested voltage at the regulator of the second cp3 and got 9 something volts so I assume that is fine. I just have never seen a truck that has high injector return rates not have any other symptoms of injector failure.

 

[slipclutchms]

I just had a thought...............would the CP3 sound strange if it was dead-headed against something?