So, I'm super bored at work, so I figured I would write this.
Edit: Hey, I got included in the Best of Oppo!
This is a while back when I was working on the 4.5L V8 diesel (LMK) that was supposed to go into the GMT-900 1500 trucks. My specific job was the cold start calibration. Basically my job was to calibrate all the engine parameters to get the engine started at all temperatures (despite being called "cold start").
Our official limits were down to -29C at sea level and mid-altitude (~5000ft) and -20C at high altitude (all without a block heater). My unofficial record for a Duramax (when I was working on those later) was -36C at sea level. One of the biggest issues that keeps us from starting lower is battery power. Even with 2 batteries and 0W oil, we would only crank at about 50RPM at the coldest temps, and the system voltage would drop under 5V during compression events. The lights on the dash would fade in and out as I was cranking. In fact, the vehicles systems are only required to function down to 5V for a short time, but I remember seeing ~4.7 occasionally and it would still crank. I tried doing a start at -40 just to see if I could do it, and the starter just clicked. Even with full batteries, it just couldn't turn the engine.
If the engine was started when the coolant temp was above about 15C the emissions calibration would take over immediately after the engine start. If it was started below that then I would control the injection timing, boost, rail pressure and other things for a while until the engine warmed up and it went over to the emissions cal.
My co-worker that was doing the LML and LGH calibration and I would always travel together to do our testing. In this case we were in Colorado doing mid and high altitude testing. In Denver we leased space from a testing company that had a cold soak room as well as emissions testing capability. At high altitude we had very high-tech cold starting facilities up in Silver Plume, CO just off of I-70 at an altitude of about 9000ft. By high-tech I mean, reefer semi-trailers. Dug into the dirt. At the edge of a borderline ghost town. The truck barely fit into the trailers and you could always tell which development trucks were the cold start trucks because they always had some scratches on the passenger side. It was just impossible to go in and out of the trailers that many times while trying to bias the truck to one side so, you know, we could actually get out, without scraping the side. They have since moved them, but for a long time we would base out of Denver (and do testing at "mid-altitude", and run up into the mountains everyday to do our testing at 9000ft.
One day after a test my colleague came back from a drive and said that he blew the transmission in his truck. It would idle and move the truck on level ground, but that's about it. It didn't have the torque carrying capacity to accelerate or even go up a slight incline, so there was no way he could drive it back to Denver. We called up a flatbed tow truck and when he eventually showed up we slowly drove the damaged truck to the base of the tow truck, but it wouldn't drive up the sloped bed. For some reason this tow truck didn't have a winch or even come-alongs to load our truck so we were stuck.
Except, I still had my (actually another colleagues borrowed LMK) that ran perfectly. I was still fairly new at this point, but my colleague said we needed to get this truck back down to base so he told me to use mine to push his truck up onto the flatbed. At this point the tow truck driver is in the damaged truck and I line up behind him, put it in 4 wheel drive and start to push. After a bit of wheel slip, we started moving. At first the bumpers lined up and there wasn't a problem, but as his truck started up the ramp his bumper rose up and started smashing in my grill. I stopped for a second and he just said "Go!" so I kept pushing as this bad crunching sound was coming from the front. The whole time I'm thinking these trucks are development vehicles that are hand-built and cost a hundred grand and I'm just smashing them up like it's nothing.
Once we got his truck where it needed to be I backed down and the tow truck driver jumps out of the truck and was astonished. He was like "I've seen a lot, but I've never been a part of something like that before!".
After that the LMK basically had no grill left, and I felt bad having to give the truck back to the colleague I borrowed it from for my testing. Luckily we had enough old trucks laying around that the mechanics were able to sorta swap in a new grill once we got it back to Milford.
That is certainly not the only truck I damaged during my testing, but it is the only one where I did it intentionally!
