X15 rough idle issues

[Valley11]

n the topic of X15. I have a 2018 X15 565hp. Demandated and running 605hp by Uni 2 years ago. Only 90,000km on truck the other day started to idle rough and smoke white haze. Rev up to around 800rpm smooths out and stops smoking. Once in awhile on start up runs smooth and doesn’t smoke never will safety twice in a row like this tho. Injector #1 was bad put new one in didn’t change. Sent all injectors away to get tested found all were gummed up do to lack of lubricant they said. They clean and set all injectors reinstalled them and acts the same. If I snap the throttle it will roll coal. While running truck no loss in power is noticed. Checked imap sensor exhaust back pressure sensor and tube all clean. Returned truck back to stock file started truck same rough idle and haze smoke rolls coal if snap throttle. Any thoughts what else to check?

[Waterloo]

Injectors... Do you have a Quickserve account? I would go there and look up their trouble shooting protocols on testing the injectors. Gummed up due to lack of lubricant? Sounds like snake oil to me. With that high of a HP setting on a motor that is not really capable of staying together under the stress, the injectors would be the first thing I would dig into. Me, I would turn the HP down, sounds like you did, and change the gearing in the rear end if you need more oomph.

May want to inspect the fuel and metering actuators too... I still think it is injectors.

Oh, the fuel pump, you do know about that, correct? 400,000 miles they need to be rebuilt or replaced.

[tree98]

As Rawze always says....... will it pass a leakdown test??

I think whoever told you the injectors were gummed up due to lack of lubrication is an idiot.

[Valley11]

I didn’t turn hp down prior demandate file went back in. I am concerned that maybe it could cause issues down the road as it wasn’t supposed to have hp added even tho they come in the 605hp from factory. Mechanic said it passed injector performance test but I should do or make sure leak down test was done

[tree98]

(01-22-2021 )Valley11 Wrote:  Mechanic said it passed injector performance test but I should do or make sure leak down test was done

Yes do the leakdown test.

[Rawze]

(01-22-2021 )Valley11 Wrote:  n the topic of X15. I have a 2018 X15 565hp. Demandated and running 605hp by Uni 2 years ago. Only 90,000km on truck the other day started to idle rough and smoke white haze. Rev up to around 800rpm smooths out and stops smoking. Once in awhile on start up runs smooth and doesn’t smoke never will safety twice in a row like this tho. Injector #1 was bad put new one in didn’t change. Sent all injectors away to get tested found all were gummed up do to lack of lubricant they said. They clean and set all injectors reinstalled them and acts the same. If I snap the throttle it will roll coal. While running truck no loss in power is noticed. Checked imap sensor exhaust back pressure sensor and tube all clean. Returned truck back to stock file started truck same rough idle and haze smoke rolls coal if snap throttle. Any thoughts what else to check?

Also you should not rebuild electronic injectors at an injector shop. Here is my thoughts on this...

http://rawze.com/forums/showthread.php?t...67#pid4367


and like mentioned... did it pass an injector leak-down test before pulling them out? --- and does it pass now that they are back in?. - there are proper procedures to follow for this type of stuff instead of blind-mans guessing and wasting money.

[Rawze]

(01-22-2021 )Valley11 Wrote:  ... Demandated and running 605hp by Uni 2 years ago.
...

you might want to get with him or mommaburt on here and see if there are updates to your program avail. 2 years ago is a long time in the world of custom engine programming.

[Valley11]

Today I did an injector leak down test and it passed built to 29000psi dropped to 23000psi after 30 seconds allowance is 21000psi drop. Check low pressure side of fuel system restriction pressure lift pump pressure all passed. Did cylinder cut out test found that #1 cylinder cutting it out the haze out of the pipes would clear up and come right back with it back on. Cutting out any other cylinders the haze was always there. According to that o would say there is an issue with #1 cylinder. That’s as far as it got today the shop was full of raw fuel by the end of all that

[tree98]

Thats WAY to much drop. It shouldn't really drop much at all. I think the spec that Cummins says it's still ok is a little over 4000 in 60 seconds. Does it go all the way down to a few hundred if you keep watching it, or does it level off around 10k-12k ?

I just looked it up on quickserve and it does say (as you said) a 21,756 psi drop or more in 30 seconds is an indication of a high pressure fuel system leak. I think this must be a misprint.