Engine/Transmission (1994 - 1998) Smoke at high RPMs?

[Hvy-DCZ]

Probably a dumb question, but do you (ya'll) push a fair amount of smoke/haze at higher RPMs when really leaning into it (~2500 at highway speeds)? I notice when getting into it pretty good I seem to blow a lot of haze / smoke. Not sure how much is really normal. My #8 is mostly forward, and I can hit ~30 psi on boost.



For some reason I'm feeling like something is not quite right. It has ~147k on the clock. Doesn't miss per se, but doesn't feel right over 2k. Still strong to 2200, but will rev hard beyond 3k, though I rarely rev past 2500.



My fuel consumption hasn't improved too much since I got my DTT... . Fun factor increased too much. Blaming it on winter fuel.



TIA,

Hvy

 

[Johnstra]

Mine does the same thing (smokes at high RPM). I think it's normal. Recently my truck has gone from grayish to black smoke when I jump on it at high RPM. This was even before I installed my #10 plate.



What makes you think something is not right?



-john

 

[Hvy-DCZ]

Thanks for the response. My smoke is also grayish/black.



Not sure why I get the feeling somethings not right... I think I expect it to sound/feel solid and strong all the way to 3k. It's like there is a mild harmonic or very slight virbration in the motor that seems to be less than perfect beyond 2300 RPM. If accelerating, it blows smoke too, which isn't my favorite thing to do. I don't mind a good black puff pulling away from a stop light, but not into a long gray/black cloud running down the freeway.



Wonder if my injectors might be dirty or tired? Only 147k on the clock. I use Lucas diesel additive regularly.



Any input would be appreciated.

Hvy

 

[Johnstra]

I think our engines behave very much the same way. When I give heavy throttle and get RPM up past 2300 or so, I'd describe my engine as feeling kind of ragged. It's not smooth sounding/feeling.



So I too would like to hear from the guys that really know the 12V well and how it behaves and feels at higher RPM. Is this *ragged* feeling typical or does it indicate something's not quite right?



-john

 

[Johnstra]

This ARTICLE, which is referenced in a different thread, discusses something that might be the roughness we feel at higher RPM. It says there's a point in the RPM band when the flyweights in the P7100 that control the governor transition from being held strictly by the large idle springs to being held by the smaller springs. At this pointer the article says the engine runs rougher. From this, I suspect what we're describing is perfectly normal.



I'd like to hear if others experience the same thing on their trucks.



-john