Old school vs. computer diagnostics on a 2008 Freightliner

I used to swear by my manual timing light and listening to the engine knock to set injection timing. After I picked up a used Autel scanner at a swap meet in Tulsa last spring, I quit doing it the old way. The computer caught a 2 degree offset I never would have heard, and that saved me from pulling the head on a customer's truck. Has anyone else switched over and found the digital tools are actually better for older stuff too?

3 comments

3 Comments

hall.joel1d ago

Read a writeup in Diesel World a few years back where a guy put a 12-valve on a chassis dyno and the wideband O2 sensor showed a lean spot at 2,200 RPM that sounded perfectly normal. He'd been tuning by ear for twenty years and missed it. That article got me to buy a used MicroPod for my 7.3 Powerstroke. Now I can data log a whole afternoon drive and see exactly where my injector pulsewidth starts acting up. Old school still has its place for quick checks but computers catch the stuff your ears just can't hear.

angela_harris1d ago

I was the same way with my old Snap-On timing light and a stethoscope to match injector clicks. Then I plugged a cheap scan tool into a 2000 International and it told me the crank sensor was drifting while the engine seemed fine to my ear. I felt like a guy who'd been using a sundial when digital watches were already at the pawn shop. The computer caught a lazy injector that I'd have chased with a compression test and a prayer. Now I keep the old tools for the nostalgia factor, but that scanner paid for itself on the first fuel mileage complaint.

michaeld4822h ago

Made me feel better about the time I spent an afternoon swapping relays on a 6.0 trying to fix a no-start, only to find out my scanner's PID list was showing a 50 psi drop in high pressure oil that I'd been too stubborn to look at. Guess my mechanic's stethoscope doesn't hook up to a laptop.