c/diesel-mechanics

Question about the $1200 Jasper reman I dropped in a 6.0 last fall

Did that Jasper rebuild save my shop hours or just burn my customer with a ticking time bomb because that thing already has a weird knock at 15k miles and I'm starting to wonder if those cheap in-frame kits from the parts house would have been smarter.

Question about an old master tech's advice on injector timing

Had a 30-year veteran at the shop in Tulsa tell me last week to stop chasing factory specs and listen for the knock instead, and now I'm wondering if I've been overthinking 90% of my rebuilds since I started.

30 minutes turned into 4 hours on a simple injector swap

I had a 7.3 Powerstroke in my shop last Tuesday that just needed one injector. Simple job right? Well the glow plug tip broke off in the prechamber when I pulled it. Had to pull the head off to get it out. Customer was standing there watching the whole time too. That extra labor cost him almost $600 more than the original quote. Has anyone else had a straightforward job just totally fall apart like that?

Spent $600 on a fancy injector puller kit and it was junk

Bought a Master Injector Puller set from a tool truck last spring. First time I used it on a 6.7 Powerstroke, the adapter threads stripped out. Cost me another $200 to have a machine shop fix the head. Went back to my old two-jaw puller and never had an issue since. Anyone else get burned by overpriced specialty tools that don't hold up?

I used to rebuild injectors in a clean room now I do them in my truck bed

For 8 years I worked at a shop in Tulsa where we had a sealed off room just for injector work. HEPA filter, static mats, the whole deal. Took it for granted. Got laid off last March and started doing mobile work. First time I had to rebuild a set of HEUI injectors in a dusty parking lot I panicked. But honestly? Wipe everything down with brake clean, work fast, bag the parts as you go. Done maybe 30 sets this way now and zero come backs. Has anyone else had to downgrade their workspace setup and found it works fine anyway?

Heard a guy at the parts counter say never use impact guns on injectors... now I get it

Surprised how a 100-hour injector service changed idle quality

Has anyone else seen a set of injectors that looked fine but turned out to be the whole problem?

I think everyone's wrong about oil change intervals on newer trucks

At a shop in Phoenix last spring I had a 2020 Ram 2500 come in with 45k miles running great. Owner had been going by the computer every 15k miles like the manual says. Everyone at my shop was freaking out saying that's way too long between changes. But I pulled the filter and sent the oil to Blackstone Labs and it came back fine. Now I'm starting to think these 15k intervals are actually fine with the right synthetic oil. Has anyone else actually tested their oil instead of just guessing?

The time I tried chasing a fuel pressure issue on an older Cummins ISX and swapped three sensors before finding a $12 crimp fitting that was loose under the cab.

Spent last Saturday in the shop tearing my hair out over a 2015 ProStar that kept dying on hills, only to realize a bad ground connection at the frame rail was the real culprit, and now I'm wondering how many of you check every single connector before throwing parts at it?

That injector trick I nearly ignored saved me 4 hours

Had a 6.7 Powerstroke in the shop last Wednesday. Rough idle, white smoke, the works. Figured it was a bad injector right away. Pulled the valve cover and saw the usual stuff. But instead of grabbing my tools to yank it out, I remembered this old tip from a guy I met at a parts counter in Tulsa. He said try running it with the harness unplugged one by one. Thought it was dumb but gave it a shot. Third injector from the front, the idle smoothed right out when I unplugged it. Turned out it was a loose connection at the harness, not a dead injector at all. Saved me pulling the whole fuel rail and buying a $400 part. Anyone else ever find a bad connection that acted just like a dead injector?

Lost $200 on a reman injector that was crap from the box

I picked up a reman injector from a discount parts place in Nashville last month to save some cash. Installed it in a 2012 Cummins, took me about 3 hours with all the bleeding and test drives. Truck ran rough still, so I pulled it and sent it back. Shop refunded me but I lost the $200 in labor and downtime. Has anyone else had bad luck with these reman parts from the smaller suppliers?

That job at the quarry in Ohio made me ditch impact guns for good

I was working on a loader out at the Miller Brothers quarry near Zanesville last fall. My 1/2 inch impact just couldn't budge a rusted bucket pin, even after soaking it with PB Blaster for 20 minutes. A 30 year old guy named Dave walked over with a 4 foot cheater bar and a socket, and popped it off in 30 seconds with no power tools. Has anyone else switched to manual tools for heavy rusted shit because impacts just spin and waste time?

Can we talk about that injector puller I bought from a random truck stop in Ohio

I dropped $150 on a puller at a Pilot in Ohio last month because I was in a hurry and figured it'd do the job. Turned out the threads stripped on the third injector and I had to borrow a Snap-on from a buddy to finish the job. Anyone else get burned by roadside tool purchases like that?

Switched my mind about pre-filtering diesel after a bad job in Rapid City

I used to think inline pre-filters were just an upsell from parts shops, but last month changed that. I was working on a 2015 Freightliner Cascadia that kept bogging down under load. Customer swore he just had the fuel filters changed 500 miles ago. I pulled the water separator and it was packed with crud, like little black specks and sediment. Found out his supplier had a bad batch of diesel with algae and rust particles. The pre-filter on a buddy's recommendation caught most of that before it hit the CP4 pump. That pump is a $3,500 fix if it goes, so now I see the $40 pre-filter as cheap insurance. Anyone else run into bad fuel from a specific station or region?

Aftermarket injectors vs OEM on a 6.0 Powerstroke, no contest

I swapped a set of cheap reman injectors into a customer's 2005 F-350 last month and within 200 miles it was stuttering and smoking like crazy. Pulled them out and put Motorcraft remans in from the local dealer, cost about $400 more but the truck runs SMOOTH as glass now. The cheap ones just can't hold the same idle balance on these HEUI systems. Has anyone else had better luck with a specific aftermarket brand or am I wasting my money on OEM?

Spent $600 on a Snap-On torque wrench and snapped a bolt anyway because I forgot to set it back to zero before putting it away

Took me a full afternoon to extract that broken bolt from an old Cummins block in a hurry, and now I'm wondering if that premium cost was just paying for the vanity of having the shiny truck come to my driveway - has anyone else had a cheap torque wrench actually outlast the expensive ones?

Spent $80 on a cheap torque wrench from Harbor Freight and it ruined a head gasket job

I figured I'd save some cash and grabbed one of their Pittsburgh Pro wrenches for an 18-bolt Cummins head job I had last month. Set it to 90 ft-lbs like the book says, clicked three times on each bolt, felt fine. Got the truck fired up and within 20 miles it was pushing coolant out the overflow. Pulled the head back off and found two bolts that were barely at 70 ft-lbs and one that was way over. Had to buy a new gasket and spend another 6 hours redoing it. Lesson learned, I just dropped $200 on a Snap-on digital torque wrench that I'll probably never touch again but at least it won't blow my work up. Anyone else get burned by cheap torque tools?

Hot take: I ragged on diesel additives for years until my fuel gelled at -15F last winter

Was stuck on a job site outside Nashville at 4am with a truck full of injectors and zero heat. Told my dad about it and he just laughed, said he's been using Power Service since 1998, so I finally tried it and haven't had a cold start issue since. Anyone else have a product they swore was snake oil that proved them dead wrong?

Had my injector stick open on I-25 outside Denver last month

I was hauling a load of feed between Denver and Colorado Springs when the whole thing started shaking like a washing machine. My 6.7 Cummins pushed 50 psi of oil pressure into the return line and filled the crankcase in about 15 miles. Who else has had injector problems ruin a perfectly good run?

That moment my air ratchet crapped out mid-bolt on a wet Wednesday

I was under a 2015 Freightliner Cascadia out in the rain last month, working on a drum brake job at a truck stop in Ohio. Third wheel nut was rusted on good and my Ingersoll Rand 2135 just gave up. No warning, just stopped turning. Had to finish that one with a breaker bar and a cheater pipe while getting soaked. Took me an extra 20 minutes and I nearly lost the nut in a puddle. Swapped it out for a used Snap-on I found at a pawn shop the next day for $60 and it's been fine since. Anyone else ever have a tool die on them at the worst possible time?

Unpopular opinion: I think digital tuners are ruining diesel work

Was out in Odessa, Texas last month helping a buddy with a 6.7 Powerstroke. He was stuck on a code for hours with his laptop. I walked over, listened to the idle for 30 seconds, and pointed at a fuel injector harness. Fixed it with a multimeter and my ears. He spent $400 on that tuner and it still missed the obvious. Am I the only one who thinks we rely too much on screens now?

Talking with an old diesel tech at a parts counter made me rethink my approach to injector timing

I was at a Fleetpride in Phoenix last Tuesday grabbing some filters, and this older guy, must have been in his 70s, was waiting too. He saw me ordering a timing kit for a 5.9 and just goes "you planning on actually setting that, or just throwing parts at it?" Kinda caught me off guard. He started talking about how these newer guys rely too much on the scan tools and don't check mechanical timing by hand anymore. Said he caught three trucks in the last month that had the timing off by a few degrees because someone trusted a sensor reading. Made me realize I've been doing the same thing lately. Anyone else have an old timer call them out on something basic like that?

PSA: That 'cheap' injector puller cost me $200 and a full Saturday

I tried saving $50 by buying a budget injector puller set from a parts store in Phoenix last month. First injector came out fine, but the second one snapped the puller clean in half with the injector still stuck. Had to call a buddy who brought over a Snap-On kit and it took us 4 hours to extract the broken pieces. Has anyone else had a cheap tool fail at the worst possible moment?

Just realized I was torquing head bolts wrong for years

Used to just crank them down by feel. Thought I knew better. Then a guy named Jake at a shop in Nashville showed me the torque-to-yield method on a 6.7 Powerstroke. Tried it on my own truck last week and zero leaks. Anyone else skip the torque wrench for years?

Chased a fuel leak for 2 hours and it was just a loose clamp

I was working on a 2005 Peterbilt 379 last Tuesday and it was dripping diesel like crazy. Checked the injectors, the lines, even pulled the filter housing apart. Finally I grabbed a flashlight and looked under the truck from the back and saw a $2 worm clamp on a return line that had backed off. Has anyone else spent way too long hunting something simple like that?