Old timer at the shop told me to bump the timing on a 7.3 Powerstroke by 2 degrees

He swore it would wake it up and fix the cold start stumble. Tried it on a customer's truck last month and it ran worse, threw a code for injection timing. Anyone else had that advice backfire?

2 comments

2 Comments

perez.cole3d ago

You ever have a buddy swear by something and then it bites him? My friend tried that on his 7.3 and it started knocking like crazy after a week. He ended up having to reset the computer just to get it to run normal again.

lily_sullivan823d ago

Hold on, I gotta push back on this one hard. That old timer's advice isn't some hack, it's a well known trick for the 7.3 if you know what you're doing. Your customer's truck probably threw a code because you didn't clear the PCM's learned values after the adjustment, or you bumped it too far past 2 degrees. The cold start stumble is a real thing on these old engines and a tiny timing advance helps the injection pump fire off better when the glow plugs are struggling. Your buddy's knocking noise wasn't from the timing bump, it was likely bad fuel or a failing injector that finally gave up. I've done this on three personal trucks and two fleet vans over the past ten years and every single one started smoother and pulled harder on the highway without a single code. You gotta zero out the base timing with a scan tool first and make sure your harmonic balancer isn't slipped, then it works perfectly.

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