surging engine braking ??

[Alex S]

Has anyone else noticed this? Sometimes when engine braking (ZF5) in the upper RPMs (about 2500 area) it seems that the consistency of the engine braking kinda fluctuates and seems like it surges for a brief moment (kinda like it lost compression for a second). But it dose not always happen. Anyways today i noticed this "surging" was much worse/noticeable and the engine has been running a bit more rough

any ideas?

hope someone has experienced this as well

 

[typ4]

Your injection pump is telling you its not happy.

 

[NMB2]

I engine brake all the time when I'm towing, I have never felt this.

 

[Alex S]

Yea it's a strange problem. Also the idle rpm fluctuates a bit sometimes about by 200 rpm

 

[motoshop]

I'm having the same problem with the idle surging about 200rpm. In the morning when its cooler (I'm in Las Vegas so we're talking about 70 degrees), it will surge even worse. IP failing?

 

[dieselgiant]

Mine did something like this - "Down shift to 2(E4OD) on the column, engine revs up truck slows, then suddenly doesn't slow and exhaust note is quieter. Idled normally right after that" It's only done this to me twice. When I down shift it revs to 3400-3500rpm, 55mph is when I normally do it. At the time I was battling fuel and air intrusion problems, so fixed the problems and now its back to normal. How many miles on the IP?

And when I think about it, it was around 2600-2700rpm both times when it did it

 

[MidnightBlade]

Mine doesn't surge when I down shift but when it idles it has a lope to it like 2 or 3 cylinders aren't firing. I know for a fact my IP and injectors are goin downhill fast so we'll see if it still does it after the refreshed fuel system.

 

[Dieselcrawler]

my big truck does it. normally when my first fuel filter is clogged and the motor is starving for fuel. i replace that filter and it stops doing it.

 

[Diesel JD]

First guess, plugged fuel filter, 2nd guess, bad metering valve on the IP. You could dose it with some fuel additive to try to get it unstuck, most of these are OK with biodiesel also.

 

[towtruckdave]

Mine did that everyday until last Sunday-when I put on a new IP.