The last NASA Utah event of the year, the Tres Duro. Three track configurations in one day on Saturday (Outer, East, and Full), and then Sunday a full day of running the 4.5 mile, 23 turn full track. Awesome!
Earlier in the year I made a comment about my car being "nearly flawlessly reliable"... I knew I should have kept my mouth shut, and I knew it was too good to last. Lucky for me, it waited for the last weekend of the year for all hell to break loose.
Saturday went pretty smoothly actually. Four sessions, no problems, all in all a good day at the track. Towards the end of the day I felt that the car was understeering a bit more than I wanted. Maybe my driving was worse than usual, or maybe my tires were heat cycled out. Maybe I was just pushing it hard enough that I was revealing problems that I didn't know where there. Either way, I was either turning in too early and then pinching the corner exit, or turning in at the right time and missing my apex. So that evening I decided to try something and lowered the front of the car by about 1/2". In theory, that should transfer some weight to the front, and also soften the front by lowering the roll center. Both ought to make it turn a little better. The next morning in the first session of the day the car felt fantastic. The handling issues from the previous day were gone, and in my first lap I dropped 1.7s off of my best time from the previous day.
This bliss lasted all of a lap and a half before the battery light on the dash came on. Less than half a lap later it started missing, not enough power to fire the coils anymore. My guess at this point was that my alternator belt had exploded, or the alternator had simply failed. I pitted and just made it to my garage spot before the car died completely. Initial investigation showed that the alternator belt was indeed not on the alternator pulley, but that the belt itself was in perfect shape... That's wierd. On further digging I found that my lightweight alternator bracket had failed in two places and the alternator was supported only by the tensioner. A bummer, but not unfixable. Some zip ties (yes, zip ties!) and wire later and I had a functional if completely jury rigged alternator bracket. Jump started the car, and let it idle to charge the battery. Strangely, it's idling at ~2500rpm. I hooked up the laptop and find that my throttle position sensor readings were all over the place. WTF? I figure I will try to run a session like that anyway, but the car just bogs, stumbles, back fires, etc. Not working, at all! In hind site, I think my TPS had been slowly failing all summer, and maybe longer, as I had been having some intermittent hesitations and occasional popping before, but never this bad. I don't know if it was coincidence that it failed along with the alternator issue, or if running the car at very low voltages finally finished it off.
At this point, the car is still driveable, and I do need it to get me home (~7 hours typically), so I pack up and get ready to go. When I left the track on Sunday at about 4:00pm, everything seemed just fine. No noticeable TPS related issues. I stopped for gas at the Flying J, and when I pulled back onto the main road, it immediately starts bogging and hesitating. Shit! Pull over before hitting the freeway and grab the laptop. Signal seems normal, so I decide to go for it, see what happens. Manage to get up to speed on the freeway (full throttle seems to work better), but maintaining speed it is hesitating, bucking, generally not running great. But, I am going. Figure it's going to be a LONG trip home. But over time it smooths out. It seems to be highly temperature related. It cooled off while I was packing and then worked fine, but sitting at the gas station heat soaked it enough to act up. By the time I get to Salt Lake it's "mostly" OK, just the occasional hic-up. I finally catch my wideband when it does one of it's hesitations, and see that it went very lean for a split second. Then I realize that the way it is falling on it's face when it acts up feels a LOT like fuel cut. Maybe it thinks the throttle is closed? Pull out the lap top and disable my deceleration fuel cut, and all TPS related issues seem to go away. Right on!
Pull off at the "Interstate Oasis" (south of Pocatello) for a sandwich for dinner. As I get off the interstate I look down and see my temp gauge pegged red. WTF? Coast into the parking lot of an abandoned restaurant and get out and pop the hood. Doesn't "seem" hot, no hissing, no steam. Pull out the lap top again to see what it thinks the temp is (different sending unit from the gauge). Sure enough, 250f. Damn. I figure I would start it up to see if it will pump some coolant, and to my surprise it does, temp starts to drop. Get it down to normal, and go get a sandwich. The slowest most understaffed Subway in the world makes me a sandwich, and I come back to the car. Start it up and it seems to be OK. Off we go I guess... Seems to be running OK through Pocatello, but as I get close to Idaho Falls it starts intermittently getting hot again. Coast for a little bit and it cools off. Gets hot again... worse this time. Coast and turn the heat on and it cools off. Finally it gets hot and won't cool off, and I have to pull over at the side of the interstate. Not my favorite place to be in the dark, but at least I am in a little triangle where an on-ramp comes on, and kind of behind a guard rail.
I sit there for a couple minutes and try starting it back up, but it won't pump coolant. Temp stays high. Shut if off. Try bleeding the radiator, but nothing but coolant there, no air bubbles. I (carefully!) crack the radiator cap a quarter turn (with a glove), and of course get a bunch of steam and coolant spraying out. Start it up, and it's pumping coolant again! Cools off, and enables me to get off the side of the interstate. I am maybe a mile from my exit to turn north. At the top of that off ramp it starts getting hot again, so I take the first exit off of the highway and coast into a gas station parking lot. Crack the radiator cap again and this time I just get steam, no coolant. Let it steam for a few minutes while I re-fill my three 1-gallon water jugs from a faucet on the outside of the gas station. Finally it's cool enough to take the radiator cap off. Add nearly a gallon of water, and bleed both the radiator and heater core. And off we go!
I set myself a strict "no boost" rule, and now that I am off the interstate on 65mph roads it seems to behave itself. In fact, no further issues at all, though I drove most of the way home with one eye on the temperature gauge. Finally made it home a little after midnight. At this point, I am extremely suspicious of my head gasket. This is pretty much exactly the same symptoms as when I had a blown head gasket back in '07.
Oh, and the zip tied alternator bracket held up all the way home!
Regarding the head head gasket issue, I think since I will have to tear it down pretty far to do that, I may just tear it ALL the way down and re-hone the cylinders and replace the rings. This motor has always burned way more oil than I would like... Hopefully in doing so I don't discover that it burns oil because of some bigger issue, like the idiots that built it bored it too big for the pistons or something like that.