Two-Stroke vs Four-Stroke Detergents: I was wrong about one of them

For years I swore by four-stroke oil additives for cleaning injectors on highway trucks. Thought two-stroke oil was just a small engine thing. Then I ran a bad tank of fuel through my Peterbilt outside of Phoenix and the injector stuck open. A buddy told me to run a 2 ounce per gallon mix of cheap two-stroke oil in the next fill. I laughed at him. After 200 miles of hard interstate driving, the truck smoothed out and the smoke cleared up. Now I keep a jug of it in the shop but I still question the long term effects on DPF systems. Anyone else use this trick or have a story where the opposite happened, where a trusted additive failed you completely?

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faith_schmidt18d ago

My buddy Dave runs a fleet of Kenworths out of Flagstaff, and he figured this out the hard way back in 2021. He had two trucks throwing injector codes after a bad batch of fuel from a no-name station in Needles. Dealer quoted him like 4 grand a truck for new injectors, so he said screw it and dumped a quart of that cheap Walmart two-stroke into each 100 gallon tank. Drove both rigs hard up the I-40 grade for a couple hours, and by the time they hit the top both of them were running clean, no more smoke, no more codes. He still swears by it for the older pre-DPF trucks but will not touch it on the newer ones, says the ash buildup risk is just not worth saving a few bucks. He had one instance where it made things worse though, put way too much in a little 6.7 Cummins and clogged the injector screen solid, had to drop the tank and clean the whole fuel system.