An old diesel vet told me to stop overfueling my Cummins and he was right

Guy I met at a parts store in Dallas watched me tune my 12 valve and said "you're dumping too much fuel for that turbo." I was running 250hp sticks with a stock HX35 and wondering why EGTs hit 1500 degrees on a pull. Backed the fuel plate down and added timing and the truck actually hauls better now without melting pistons. Anyone else had a old timer save them from blowing up their own engine?

3 comments

3 Comments

river_jones19d ago

Man thats a fact. Had an old cummins mechanic watch me messing with a boost elbow on a 24 valve and he just shook his head. Told me to stop chasing big fuel numbers and get the air right first. Dialed back the injectors, threw on a bigger turbo, and the truck actually tows without turning the highway into a smoke screen. EGTs dropped like a rock and it pulls way harder now.

nancy92919d ago

Oh man, I learned that the hard way too. Chasing fuel on a stock turbo is just asking for heat soak and melted pistons.

alicem2919d ago

Chasing fuel on a stock turbo is just asking for heat soak" - yeah that hits way too close to home, I felt that one in my bones lol... I was the guy running a cloud of black smoke thinking it meant power, not that I was just turning fuel into a giant pyro show. @river_jones knows what's up, I had almost the same thing happen with a old IH mechanic who watched me crank the pump on my 7.3 and just sighed like I'd insulted his dog. He finally just said "son you're making more heat than horsepower" and walked off, which was pretty humbling honestly. I backed everything down to like 80% of what I had and threw a proper intercooler on it, and now it actually pulls a trailer without me having one eye on the mirror checking for the fire department. Still feel dumb about it every time I see someone else blowing black smoke and thinking they're cool.