2001 Duramax LB7 Knocking

[rpaoness]

At first I didn't understand what you meant since I was in diagnose/repair the symptom/problem mode. I think I get it now, and yes, if that happened it's possible that I have some diesel dilution. I've been constantly checking the dipstick for any appreciable level change, and there hasn't been a significant one, but I'll check again after I button it all up and probably change it as soon as the saga is over.

There is an o-ring in the injector line design that I think is supposed to make it leak up and out of fitting/line gap instead of down into the rocker area.

[rpaoness]

I think I finally got it sorted. 5 mile or so test drive tonight went fine, no apparent skips or misses, power seems OK. I can only "see" a few live piece of data. Max MAP reading I saw was roughly 65", I think that's about 31.9-14.7 = 16 psi. I wasn't loaded and on flat ground and was just running 30-50 mph, so I couldn't hold at max load long enough to see where it really peaked.

My best guess is that it was the only-torqued-to-spec line on a less-than-perfect seat on the #4 replacement injector. I torqued all of the driver side injectors to 35 ft lbs instead of 30.

[rpaoness]

Made a 600 mile trip to Lunenburg VT and back with an ATV and a bunch of tools, no trailer. I took the cap off and ran open bed/ATV on the way there/a tonneau cover on the way back. 22+ mpg on the way up and 18 ish driving around in VT/NH and on the way back. I'm wondering if the 22 mpg fill up was just an early pump shutoff. Maybe the mpg was awesome because I was driving slow and gentle due to ATV bounce - I was too lazy to restrain well since it fit fully in the bed. We'll see what it does over the next trip(s).

Had a check engine light during the drive up due to fuel pressure regulator performance. Cleared it once and it came back, then self-cleared after a couple more drive cycles. I had intermittent regulator codes a long time ago after replacing the regulator (due to a lopey idle that it did correct), but they went away eventually on their own. I threw some cetane boost/fuel lubricity additive that I had laying around in it and I'll keep driving it until the light comes on more regularly before doing anything.

I do also now have an airbag code/light on. My first guesses from 5 min of internet reading are: 1) I managed to drop a welded-on nut "hot" from my exhaust manifold or glow plug removal attempts into a wire for the air bag sensor, or 2) I have an age-related failure of the collision "sensor or it was no longer waterproof due to age and got coolant-soaked when I pulled the upper radiator hose and that failed it. I would like to troubleshoot and repair to both get the light off and get back functional air bag performance.

[kevm14]

Just about every "look at this trooper GMT-800 still going" video has an airbag and sometimes ABS light on. I am not saying it's hard to fix but the kind of people who drive beater 800s don't bother and magically live in states that don't care. But I agree, the airbag should work as designed. I still have that Tech 2 that I borrowed back for more in depth troubleshooting.

[rpaoness]

It doesn't look like the wires are routed by the frame rail that I dropped some molten metal into. Sensor is about $180 from gm parts direct, $276 from local dealer.

https://www.gmpartsdirect.com/oem-parts ... U1NA%3D%3D

[rpaoness]

I should've had Jamie/Christine pick up the Tech 2 since I'd like to check injector balance and read airbag codes...