c/diesel-performance-chat

My $40 fuel pressure gauge almost cost me a $4,000 engine rebuild

Last Tuesday I finally got around to installing a fuel pressure gauge I bought off Craigslist from some guy in Reno. Fired up my 7.3 and the needle was dancing all over, showing 10 psi at idle then jumping to 80 when I touched the throttle. I panicked and shut it down, thinking my HPOP was toast or my injectors were done. After two days of tearing stuff apart and reading forums, I realized the gauge itself was junk, the little brass restrictor fitting was missing and it was just feeding back pulsation from the fuel pump. Slapped a $14 replacement restrictor on it and now it reads a steady 58 psi like it should. My buddy laughed his ass off watching me nearly cry over a gauge that cost less than a tank of fuel. Has anyone else chased a phantom reading only to find out the cheap tool was the problem all along?

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hart.cora•5d ago

Rolled 300k on my 7.3 and the odometer timing threw me off

I was hauling a skid steer down I-80 outside of Cheyenne last Thursday when the truck rolled over 300,000 miles. I knew it was coming for like a month, I had it at 299,800 before the job. But watching the numbers flip at 65 mph with a loaded trailer made me stop and think, this old girl has done more work than my last 3 daily drivers combined. The oil pressure stayed steady at 55 psi the whole time, no hiccups. Has anyone else tracked their exact milestone mile and felt weirdly proud for a machine?

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the_nina•6d ago

Spent $280 on a lift pump delete, wish I had done it sooner

My truck kept losing prime after sitting overnight, so I swapped the factory CP3 lift pump for a regulated return setup. The kit cost $280 and took a Saturday to install, but now fuel pressure sits rock solid at 15 psi even after a week parked. Anyone else seen a big jump in cold start hesitation after going the regulated return route?

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torres.sage•9d ago

My $800 compound turbo setup lasted 6 months before the wastegate gave out

Bought a budget compound kit for my 2003 F-250 back in March. Sounded great on the street, spooled up nice at 2,800 RPM. By September the wastegate actuator started sticking and I lost boost on a long grade near Flagstaff. Replaced it with a name brand unit for $240, but the install took a whole weekend. The cheap kit saved money up front but cost me two weekends and a tow bill. Anyone else burn themselves on budget turbo parts instead of just buying the good stuff once?

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mary776•10d ago

Used to chase dyno numbers with my 6.0, now I chase fuel economy like a grandpa

Back in 2019 I spent $4,800 on stacks and a hot tune cause I wanted to smoke out every Honda on I-10. After that fuel bill hit $180 a week for grocery runs, I flashed back to stock and now I hypermile with a light foot, anyone else trade the smoke show for saving cash?

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ray189•10d ago

Talked to a kid at the fuel pump, made me rethink my tuning setup

Ran into a college kid at the Love's in Amarillo last week. He was running a stock 7.3 with just a clean fuel system and a basic chip. I told him about my stacked tuners and he just said, "why not get one good one and learn it?" Honestly, that hit different. I spent 300 bucks over three years on budget boxes, never really dialing anything in. Now I'm selling two of them and going to a single custom tune. Anyone else ever simplify their setup and got better results?

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the_riley•11d ago

EGT dropped 180 degrees after I finally fixed the boost leak

Chased a lazy spool for months on my 6.7, cleaned the MAP, checked the actuator, nothing. Found a cracked CAC boot near the passenger side headlight last weekend, replaced it with a reinforced one, and my EGTs on the same grade dropped from 1250 to 1070. Has anyone else seen that big of a swing from just one boot, or am I missing something else?

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robertgreen•14d ago

That cold air intake delete actually woke my 6.7 up

I pulled the aftermarket cold air intake off my 2012 F-250 about 3 weeks ago and put the stock box back on. The truck had a rough idle at stoplights and I kept chasing a P0401 code that never made sense. Turned out the cone filter was letting fine dust past the MAF and it was reading way off. Now the idle is smooth and I got 2.5 mpg better on my last haul to Boise. Anyone else seen worse performance after bolting on a fancy intake?

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the_riley•16d ago

Took the old guy's advice on my twin turbo setup, glad I did

My buddy Mike at the shop kept telling me to ditch my big single and go twins for my 6.7 build. I thought he was just trying to sell me parts, but after 3 months of lag and high EGTs I finally caved. His point about spool time and towing load made sense once I actually watched the data logs side by side. Now I'm pulling my 12k goose neck at 1400 degrees instead of 1600 and it drives like a different truck. Anyone else had a shop guy prove them wrong on turbo sizing?

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the_wren•17d ago

Rant: Why I ditched my old school boost gauge for a digital readout

I ran a mechanical boost gauge for 10 years on my 7.3, thought it was bulletproof. Last month it showed 8 psi at full throttle and I nearly parked the truck thinking the turbo was done, turns out the line was cracked the whole time. Swapped to a digital setup with a pressure transducer, now I get exact readings to the tenth, anyone else deal with analog gauges giving false panic?

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gray6•19d ago

Single vs twin turbos on my 7.3, the tow test settled it

I ran my 2002 F-250 with a single 66mm for about 14 months, then swapped to a compound setup with a 38mm and 71mm last fall. Pulling my 12k gooseneck up I-70 near Vail, the EGTs stayed under 1100 on the twins, but the single would spike past 1250 on the same grade with similar boost. The spool difference was the real kicker, twins start building boost around 1800 rpm instead of 2400, which made merging with a load way less stressful. Downside was the install time, took me a full weekend plus a Tuesday night fighting charge pipe routing near the passenger frame rail. Fuel economy on empty drop about 1.5 mpg, but I got that back in cooler oil temps. Anyone else run compounds and find the lag tradeoff worth it for daily driving or do you keep it simple with a single?

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kai914•20d ago

I was wrong about tuning boxes, a dyno day changed my mind on Friday

For like 2 years I kept telling everyone a tuning box was just a waste of money compared to a real custom tune. My buddy Dave kept saying the opposite, that for my setup a good box was all I needed. I finally went with him to a dyno day at a place outside Tulsa last Friday. We strapped my truck down and the box gained 43 hp and 80 ft-lbs over my stock tune. I was so sure it would show nothing. I still think a custom tune is better for max power, but for a daily driver that I tow with, the box is honestly fine and way cheaper. Has anyone else had a dyno result that made you flip your opinion on something?

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michaelchen•20d ago

Rant: I thought EGT gauges were overkill until my pyro hit 1450 on a grade outside Flagstaff

Ngl, I ran two years without one and told everyone they were just for dyno guys, but after watching my temps climb that high on a 6% pull with a loaded gooseneck, I ordered a probe kit that same night and now I'm curious how many of you actually run a factory turbo with no gauge still.

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drew965•20d ago

That fuel rail pressure sensor failure in Waco

My 2016 Cummins started bucking like a rodeo bull about 10 miles outside Waco last Thursday. I pulled over, checked the fuel filters, and they were clean, but the scan tool kept showing erratic rail pressure readings. Took me three hours of chasing grounds and wiring before I finally swapped the sensor, cost me $85 at the local parts house. Runs perfect now, but I still don't trust that sensor design. Has anyone else had these fail without throwing a hard code right away?

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hill.andrew•23d ago

My torque wrench was 30 ft-lbs off for 2 years

I was double checking my injector install last night and decided to test my torque wrench against my buddy's snap-on unit. Turns out my cheap one was reading 90 when it was really putting down 60. Been running my truck with head bolts barely snug for who knows how long. Never had a leak but now I'm paranoid. Anyone else ever find out their tools were lying to them?

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uma685•26d ago

Swapped my edge tuner for a smart one and I'm never looking back

I ran an Edge Evolution on my '06 Cummins for like 4 years. Thought it was fine, got decent fuel numbers, truck pulled okay. Then my buddy let me borrow his CTS3 for a week. First thing I noticed was the live data actually made sense. I could see EGTs climbing before I even felt it. After 2 days of hauling my usual 12k load up I-70 near Denver, my trans temp stayed 30 degrees cooler just because I backed off when the gauge told me to. That one feature alone sold me. Now I watch my boost pressure like a hawk and my truck hasn't felt this healthy since I bought it. Anybody else made the jump from a basic tuner to something with full monitoring?

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brian_ramirez•1mo ago

PSA: That old trucker I met at a Pilot in Ohio told me to stop idling my 7.3 for 20 minutes before shutting it down

He said letting it cool down for 3-5 minutes after a hard pull is plenty, anything past that just wastes fuel and wears the glow plugs faster, and he's been hauling freight since the 80s, has anyone else heard different from their mechanic?

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uma685•1mo ago

Had a injector fail on I-75 south of Atlanta last month, changed how I buy parts forever

I was hauling a load of lumber back from a job near Macon when one of the injectors decided to crap out right near the truck stop outside of Griffin. Lost power fast, had to pull off and call a mobile diesel guy. He got me going with a used injector he had in his truck, but it cost me 200 bucks cash and I was stuck there for 4 hours. After that I started buying parts from a local diesel shop instead of the online places that ship slow. Anyone else have a breakdown on a highway that made you switch up where you get your parts?

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jennifer965•1mo ago

Wasted $400 on a 'stage 2' tune that was pure garbage

I fell for one of those mail-order tuners for my 6.7 Powerstroke last spring. The guy on the forum swore it would wake up my truck and pick up 80 horsepower easy. Spent $400 on the whole kit and loaded it up in my driveway. First tow with my 28-foot camper the trans started slipping on a hill near Chattanooga. Pulled the tune off after 3 days and the check engine light was on for a week. Ended up paying a local shop $150 just to flash it back to stock and tell me the tune was way too aggressive. Now I just stick with the canned tunes from a reputable brand. Anyone else get burned by a shady tuner that promised big numbers?

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paul346•1mo ago

That cheap boost tube fitting I bought on eBay actually held up

I needed a 2.5 inch 45 degree silicone coupler for my 7.3 build and grabbed a $12 kit instead of the $50 brand name ones. After 3 months of daily driving and a few hard pulls up a grade on I-5 it hasn't slipped or blown off once. I even double clamped it like I always do but still figured it would leak by now. Kinda makes me wonder how much of the markup is just for the name on the box.

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danielhenderson•1mo ago

Finally got my 6.0 to hit 400 hp on the dyno after 3 blown gaskets

Spent all last week swapping head studs and tuning on my 2005 F-250. Third time was the charm I guess. Hit 402 hp at the wheels and the smoke cleared up way better than I expected. Anyone else have a project that just fought you every step of the way?

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the_lucas•1mo ago

Was dead set against a tuner on my 7.3, buddy proved me wrong in 45 minutes

My buddy Jared has been telling me for 2 years to put a Hydra chip on my 2000 F-250. I kept saying no, stock is reliable, I don't need the extra heat or stress. He finally dragged me to his shop last Saturday and let me drive his truck after he tuned it. His 7.3 had way more pickup on the highway and still ran at 190 degrees coolant temp. I ordered one that night and put it in Sunday. Has anyone else held out on tuning for a long time then got surprised by how well it actually runs?

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margaret99•1mo ago

Hot take: bigger injectors aren't always the answer for towing

I was at a diesel meetup in Odessa last weekend and saw two guys arguing over a 6.7 Cummins. One was saying you gotta dump $2k into big injectors for any real power gain, the other was all about tuning and keeping stock nozzles. I've been running my truck with just a mild tune and a lift pump for towing heavy loads and it pulls fine. So which side is right for daily driving and hauling, or is it really just about what you use it for?

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terryf62•1mo ago

TIL most guys are tuning their 6.7 Powerstrokes completely wrong on the EGTs

I was at a diesel meetup in Raleigh last Saturday and watched this dude with a '19 F-350 keep hammering it while his pyro was reading 1450 for like 10 seconds straight. He thought that was normal because his tuner guy told him it was fine. My own truck has 180k miles and I learned the hard way after cooking a turbo at 132k that you gotta stay under 1250 for more than a few seconds. Anyone else see people just ignoring their exhaust temps at the track or on pulls?

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west.anna•1mo ago

That one Thursday where my truck ran 12.4 all day at the track

Last spring I was out at Bandimere Speedway with my 6.7 Cummins and everything just clicked. I mean we did three back-to-back passes and every single one was within a tenth of 12.4. No defueling, no heat soak, nothing. The air was cool maybe 55 degrees and my intercooler was actually working right for once. Has anyone else had a day where your truck just decides to behave perfectly?

2 comments