01 ch600 running rough

[Dalton1]

I have a 2001 CH612 with a 310hp E7 Etech that is running rough like it's miss firing and blowing some light grey smoke, no change at low mid and high rpms. The CEL comes and goes, it flashes a 3-4 for engine position sensor, the tachometer is working and seems to be accurate, is it run off the same sensor? Is it the sensor on the front cover?

I've ordered a new position sensor but wanted to see if anyone had any thoughts as to what it could be or other things to check. The truck does have very high mileage, 850,000 34,000 hrs 

thanks in advance!

[Dalton1]

Update, I checked the eup's by briefly shorting them out, when I short out cyl 5 there is no change, and all the other made it run rougher, so I'm assuming that's the cylinder that's missing.

i swapped the #2 and #5  eup's and there was no change, cyl 5 still no change, what else could be causing that cylinder to miss? And how can I test it?

[fjh]

If the eup swap did not move to the other cyl you either have an injector issue OR a bad valve if its a bad valve you will have blu white smoke

Pull the injector have it tested! your smoke color sounds injectorish!

You can also swap the injectors  hole to hole to prove it out! 

Edited May 28, 2017 by fjh

[Dalton1]

I'll try swapping the injectors tomorrow, thanks! Hopefully that solves it 

[Dalton1]

Update, swapped the injectors, made no change, cyl 5 still missing, while in there notice the the cyl 5 exhaust valves were adjusted to tight, adjusted the valves and it runs great now, I still get a little smoke but I imagine that's because the engine has close to a million miles on it.