High rpm miss

[Cullen ledy]

Hello guys new member here, I drive a 95 cl700 e7 454 part time for my buddy’s construction company, mostly run equipment but spend a fair amount of time in the truck. This all started last winter when we were hauling snow and I was getting pretty aggravated when kw’s were passing me climbing the hills up here in the U.P, so I was doing some reading and I installed a manifold pressure gauge and I was only pulling 27 psi peak boost at around 1400 rpm. I pressure checked the intercooler, it was spent, put a new intercooler on it, got me up to 32 peak pressure at 1400rpm it was better but I still had trouble pulling snow up a hill. This summer it ate a turbo so it got new one, still the same pressure. one thing that I’ve been wondering about Is it sounds like it has a high rpm miss once you get above around 1450, and the boost needle starts to flutter or bounce after 1400 and it starts to miss, what do you guys think it could be? all the valves and jakes are gapped properly... burnt valve? Bad injector? Bad pump? And the cylinder closest to the fan seems to run cool by touch but does start missing when I crack the injector line. Any advice would be great thank you!

Edited November 7, 2018 by Cullen ledy

[Mack Technician]

16 hours ago, Cullen ledy said:

 This all started last summer when we were hauling snow...…….

Lol, only in the U.P. can a guy make a living hauling snow piles out in May & June.

Have you tried splicing in a fuel psi gauge to check under load? Usually won't cause a defined hit'n'miss, but its a good, easy, start point. 

 

[Cullen ledy]

Haha whoops I wrote the post after a long day.. winter not summer, but I will get a fuel pressure gauge in it to see thank you for the input

Edited November 7, 2018 by Cullen ledy