Engine/Transmission (1994 - 1998) Popping sound WOT at high RPM?

[Cummins4Life]

2700+ RPM there is a loud or pronounced popping or chugging sound. The engine seems smooth but it just doesnt sound right out the pipe.



When I bought this truck it had a noticable chug chug chug 800-1200rpms that would shake the truck a little. After replacing the DV's and changing out to the GSK it was greatly reduced but seemed to move up the power band to around 1800rpm but its hardly noticable. Just wondering if it may be related.

 

[Vaughn MacKenzie]

Zach my hunch is it may be something with the injection pump? Have you ever replaced the overflow valve? Can you see any smoke out the pipe when it happens? It almost sounds like the plunger isn't getting a full supply of fuel before it goes into the injection phase or something like that.



Vaughn

 

[Cummins4Life]

Thats what I was thinking. The overflow valve is new or well only a few months old. Once the boost comes on the black smoke clears up and it burns clean. No puffs of grey or white. I dunno this rig has never really idled very smooth, the tach is steady but you can feel it.

 

[Vaughn MacKenzie]

Mine idles super smooth. Smoother than any truck I've owned, but part of that is the fact a manual transmission has a heavy flywheel and that smooths 'em out. Every Auto 12v I've been in has a slightly imperfect idle especially after good & warmed up or driven hard.



Vaughn

 

[tURBOdIEZEl]

check the overflow valve as said above, i would also check your timing. maybe you need to ad somemore or time it down a bit. know before my timing was advanced i was getting a popping noise when i would hold the throttle down for a couple seconds. just my . 02