We Put 20% Over Injectors In My 389 Peterbilt!

[@JLR3Truckin]

Put an air dog lift pump on the truck. I have one on my x15. Tuned at 565 from 525. Factory turbo straight piped.

[@BlueCollarCoyote]

@@JLR3Truckin make a difference? I’ve been really debating it

[@JLR3Truckin]

huge difference. Throttle response and fuel mileage truck runs smoother too. If you put one on your truck and your still having vibration issues its probably not fuel related because the truck will always have all the fuel it needs with the pump pushing consistent pressure. But still will be a possibility of injector issues. X15 injectors are very sensitive. I had all 6 replaced at 50K miles under warranty because they went out

[@BlueCollarCoyote]

I might have to try an air dog then! The vibration drives me nuts and I really feel like it’s fuel related because of the way it acts, but we’ve tested everything I can think of.. except the lift pump. And always a possibility that it’s still an injector issue since I didn’t have them rebuilt. They did say they reset them and that they were all working good but you just never know once they’re back in the truck. We have noticed it vibrates less with smaller tunes (less fuel) and now with the bigger injectors it vibrates more, at idle and through the rpm’s

[@JLR3Truckin]

@@BlueCollarCoyote sounds like the truck is commanding more fuel than the factory pump can provide. Throw and air dog at it and it will definitely tell you if its injectors or just the truck wasn’t getting enough fuel. Im not a “certified”mechanic but i work on my own stuff and was a mechanic in the military and if i had to guess i think the pump should fix your issue or give you the answer to your issue. Also if you put one on get the heater kit and change the filters to fleet guard. Fs1000 and ff5588. The air dog filters dont work well in the cold. The fleetguard ones are way better especially with the heater kit

[@BlueCollarCoyote]

@ okay thankyou! I’m gonna look into this a little more and I think I’m gonna give it a try then! I’m assuming you bypass the factory lift pump then or did you go through it?

[@gordoncurrie8130]

Have you checked the injector harness? I have owned my 2014 Kenworth sense new and always thought it never ran right. Two years ago I had some issues and was testing the return flow on the injectors and noticed when you had the injector capped off and checking the return flow I had two injectors that didn’t log a miss fire code in the ECM. I believe it was 1 and 5 when I had either of those two capped off and running the rail pressure up as per the manual it didn’t log a miss fire code for those injectors thought that was odd so I put a new injector harness on for 350.00 pretty cheap when consider the price of injectors. Maybe just double check with someone who has done the return flow test on injectors for a X15 I could be wrong but what I have found with my Cummins is you half to follow the trouble shooting steps to find the problem.

[@BlueCollarCoyote]

Might have to give that a try too, thankyou!

[@gordoncurrie8130]

Some thing else you can ask your tuner is that on this Cummins engines with the common rail fuel system is that there are 3 or 4 different modes of injection. And when you get rid of all your mandated stuff on your engine you need to lock the injectors in one mode. I learned that from a guy that helped me out with mine I was having issues with mine one day not pulling great and the next it was great and also running like shit when you cold started it in the morning. He got me a good file and you could tell right away when the truck started it ran different and better. Like you said in your video these things are kinda finicky when it comes to programming. Good luck

[@esadtoplica1214]

Just curious you still running the oem turbo or went without vgt? Bcz you running straight pipes sounds really good curious on back pressure and Jake breaks?

[@BlueCollarCoyote]

@@esadtoplica1214 full tilt manifold and s475 AirTec turbo. Definitely lose a ton of Jake power but smoother power and better fuel mileage along with more reliability

[@ScottArmas107]

I have a DD-16 now after driving a few X15’s. That’s one thing I really miss is that Cummins Jake.

[@robertbradford7892]

Seen a vibration problem on a C-16 cat be the crank balancer.

[@BlueCollarCoyote]

Replaced that a couple months ago with no difference

[@caliworks2016]

Harmonic Balancer ( crank damper) could be the problem

[@BlueCollarCoyote]

First thing I replaced.. no change unfortunately

[@thomaskraemer6583]

How many miles do you have on the motor? Might be time for a new balancer!

[@BlueCollarCoyote]

Just threw a new balancer on and it made no difference

[@RyeTheGuy]

have you tested the fuel solenoids ? iv had some weird issues with those in the past on some of are other isx engines might have a bad one causing rough runner although engine might sound smooth worth a check

[@RyeTheGuy]

@8:49 when it stumbled and hazed is the give away for me iv heard that sound before one of them was acting up. cause at that point that high pressure fuel system would have pushed any air out during all the revs my old 388 started running like that 24/7 till we swapped injectors ( wasn't necessary ) and replaced all the solenoids that ended up fixing it

[@550hpW900L]

No fuel solenoids on common rail

[@3406e]

Cummins recalled those injectors if I can remember correctly