New Installations/Got Rough Running

[speedyjdl]

I installed a set of injectors, rail cap, and a stage one CP3 today. I was getting impatient towards the end and I didn't want to adjust the back lash on the exhaust vavles. I figured that since I didn't touch the adjustment screws that I could just put the rockers back on and they would be at where they were when I took them off. So I went to start it up and after 3 tries no fire. I get out and there is fuel running on the ground and I remembered that I didn't tighten the rail cap. Did that and she fired right up. It idled good for about 5 seconds and then it started knocking and puffing out white smoke. I think that it is because I didn't set the backlash, but how could it be out from where I started? I'm going to take the valve cover off again tomorrow and adjust both the intake and exhaust valves and hopefully this solve the problem. I hope its not the injectors or something. If you guys have any suggestions please let me know.

Thanks-Speedy

 

[JStieger]

Speedy-



Sounds like you're getting late injection timing and/or low rail pressure, which can equate to late injection timing.



What you're describing happened to me too when my DD3 injectors carboned up. Off-Idle the engine sputtered, knocked, and blew white smoke until the rpm came up due to rail pressure taking a while to overcome the carboned up nozzle.



If you don't have a rail pressure gauge, you can measure the voltage off the center pin on the rail pressure sensor. From Matt400's rail pressure gauge:

First I have to thank dan. poitras for posting the OEM transducer specs from his Cummins wiring diagram which is:

0 psi = . 50 voltage return (VDC)

5801 psi = 1. 39 volts

10153 psi = 2. 06 volts

14504 psi = 2. 72 volts

20305 psi = 3. 61 volts

26107 psi = 4. 50 volts

So if you measure your voltage at idle and you're less than 1 volt (~3300 psi) and stock idle is ~5300 psi... this would probably point to your CP3 (since you got new injectors).



You could put your original, unmodded CP3 on and see what happens too.

 

[speedyjdl]

Thanks JStieger. I'll have to look into that. Another thing I was thinking about this morning is wether or not I tightened the center nut properly on the CP3 shaft. Does anybody know the torque specs on it and proper CP3 installation procedure. I was trying to go to 80lbs. but the belt would start turning and I never tried holding it.

 

[speedyjdl]

I don't know what the deal is. First I tightened the CP3 center nut as tight as I could. Then I went and got a volt meter and tested the voltage on the fuel sensor and it read between 1. 5 and 1. 6 on a cheap Walmart volt meter. Truck was still running like crap and I decided to take it for a drive and it ran terrible for about 2 miles and then all of a sudden it went back to normal.

I had both chips turned off and the truck felt pretty good. Like it did before almost with the old cp3, injectors and the chips on. Started turning the chips on and holy crap. This thing is fun to drive again. Hopefully get my FASS 150 on this week and get my twins done soon.

All smiles here!

 

[bzingre]

Air in the fuel maybe??? Should run bad for a couple of miles especailly with a new pump and injectors. Just a guess.

 

[Tomeygun]

Air in the fuel maybe??? Should run bad for a couple of miles especailly with a new pump and injectors. Just a guess.

My truck took about 10 minutes of funny idle before it smoothed out. AND that with blowing all the junk out by cranking engine without the injectors in (thats a heck of a sight)

 

[JStieger]

Tomey-



Still happy with the modded CP3? Have you got any more driving time with a DRB with the various TST settings? Also, how long did it take to swap the CP3 in hours?



Thanks!

 

[Tomeygun]

Tomey-



Still happy with the modded CP3? Have you got any more driving time with a DRB with the various TST settings? Also, how long did it take to swap the CP3 in hours?



Thanks!

I am happy with it, Although in hind-sight the stage two would have maybe been the way to go...



I have not drove anymore with the DRB, as well as when I was in KC, I drop my truck off and went into town for a couple hours. It was done when I got back. I think most people have told me 2 hours to swap a CP3, But I could be a little low on that figure...

 

[speedyjdl]

Yeah its pretty quick. You are looking at 4 nuts and a couple of fuel lines. About 1. 5-2 hrs. I wish I went with the stage 2 as well, but definately a big improvement over stock. Maybe next year. I was down at II the other day and they say they have a cp3 that flows something like 230% more than stock! It wasn't a direct bolt on though. These 3rd gens are gonna get crazy!