Marc's Public Blog - Cars

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I was looking forward to going to thunderhill again, it had been too long (since last year). It just wasn't quite done deal from the start though. After trying to guess from the weather reports whether it was going to rain monday or not, it first looked like it wasn't so I mounted my other wheels with Toyo RA-1s to replace the current "winter" tires (Toyo T1-S) a couple of days before the weekend.
On saturday morning, I managed to flat-spot my front right tire while bedding / testing my newly installed brake pads. Swell... At this point my options were to mount the tire in the wrong place (left back) and worry about the weather reports that had switched back to partial rain (those tires were not ready for rain at all since they mostly had the sticky rubber left on them, but little tread), or to take the backup car.
It came close to that, until Larry nicely answered a post on BAMO and offered to sell me his brand new RA-1s that were sitting in a garage (turned out it was the only way to get those on a saturday as all the possible warehouses in California didn't have them for same day delivery). Some running around to pick them up and get them mounted, by late saturday, I was all set. Yeah!

On the drive to thunderhill on sunday evening, I refueled at some Arco on the way, and noticed that my EGTs (exhaust gas temperatures) were shooting a bit high (more than 800C) at 110mph, so I just drove an almost decent speed on 505/5. That should have been a hint that things were slightly amiss already.
The next morning, I filled the empty portion of my tank with 100 octane, but that was only 4.5 gallons out of 12.7.

I first went out with my student to show him around the track in my car, and then later in his. He had a lot to learn, but eh, it was his first time, so that's normal.
After that, I went to have a little more fun on the track, but soon realized that my EGTs were really getting out of control. So, I called tech support (aka JasonC), took notes on what to reprogram in the Tec-II, and went to a support technician (aka MattY) to make sure the fuel enrichment and timing advance were done properly.
This helped a little bit, but still, I was running quite hot. Since Carlos was having the same issue and we both had gotten Arco 91 Kalifornia crapola gas, we figured that this week's Arco gas was probably watered down or something. We both added more fuel in our respective maps and messed with timing some more, which helped a bit. It also got a bit better for me after another more aggressive enrichment tune, and 6 more gallons of 100 octane in my tank once I had burned some by mid-day.
This is also around the time that I obliterated my AC/power steering belt (luckily it was that one), which in hindsight may be related to the high EGTs I was having, and a small exhaust leak (I think this caused my map sensor problem later). Anyway, I got to drive the last 4 sessions with no power steering, which made the drive a lot more intense (incidently, my back and shoulders were fairly sore the next day from pushing/pulling the steering wheel with such high gearing an no assist).

Matt "I'm too cool for my hair" Y

Carlos "I'm faster than you, but I can't drive 10 10th right now"

Jason "My blower is bigger than your turbo, so there!" W

Marc "Look at the back of my car, that's all you'll see Carlos" M

bling bling! represent! :)

By the end of the day, I was able to run the open track at full bore and came down to 2:18-ish (maybe 2:17), which was decent but not as good as I did last time when I didn't have all those mechanical problems and was much more focussed on driving and shaving off imperfections. Eh, at least I got a nice "you are positively insane" comment from the last passenger I got. All in a day's work... :)
Just for the record if you were wondering :), I never got close to losing control of the car, left the track with even one wheel, or made any dodgy pass, but with the RA-1s, I could drive very hard and keep a nice controlled yaw angle through turn 2. For that matter, even Bonni tried to get me off track by getting off turn 10 backwards and throwing dirt right in front of my car, but she failed too :)

Now, on the mechanical side, my clutch started acting up again, just like last time I went to TH: somehow it wouldn't always downshift from 4th to 3rd before turn 2, or 2nd to 3rd in turn 11 (mostly due to temperature apparently). This was annoying in itself, but on top of that in turn 11 while struggling to shift back to 3rd, I must have messed up a bit, and the gear somehow slipped in 1st, when I was at the top of 2. Ouch!!! I was actually expecting to see my engine drop on the road in my rear view mirror after that, but somehow it was still working...

Things became more gloom when I came back to my car that was idling on the paddocks to circulate oil through the turbo while it was spinning down and cooling off, and I noticed that the engine wasn't running anymore. Ok, maybe a fluke, so we drive to Willows to refuel, and when I'm ready to leave with my BAMO buddies, my car half starts and dies, and then won't start. Damn...
I pull out the laptop and connect to the engine diagnostic/reprogram port, and notice that one of the sensors is reporting failures: the MAP sensor (manifold air pressure). The Bamo buddies who had stopped to help me start looking at it, MattY at the laptop, and Carlos at the engine bay, and Carlos finds that one of my vacuum lines by the manifold was very hard and half pinched (hard due to temperature under the hood I'm sure, and pinched due to poor routing). Carlos cut it, re-routed it, and that took care of it.

We head out on Hwy5 south, but I end up driving slow: 55-60mph because I noticed that my EGTs are quite high. Argh... After pulling over, I tried to re-upload my engine map from the track (over-rich) even if I'm not supposed to need it and it might knock with less 100 octane gas in the tank. Car barely starts and move after that upload. Argh! Ok, now I try the middle map I had (a little less rich), and the serial connection fails half way through the upload, and I can't see the engine computer on my laptop after that anymore. Argh, argh, argh!
At this point, I was quite stressed because it looked like a half upload was a failure you couldn't recover from. Yet, somehow after restarting the stupid wintec2 crap software, I finally got an upload to work, and the car was finally on its way. EGTs were still high (more than 800C for cruising), but I was able to drive 85mph or so.
Then, I noticed on the way while looking at the real time engine stats on the laptop that it was showing much lower RPMs than I was driving (2900 rpm when I was doing 4500 or so). Since I know my gearing, I knew that my dashboard was right, and the laptop (and therefore ECU) wrong. While I'm not much of a mechanic, I knew enough that my ECU being off on RPMs by 1800rpm is very wrong. For that matter, my engine won't run if it's off by an 8th of a turn, never mind more than ten thousand times that. Anyway, the car limped along up to Mell's diner on Hwy 80, and after talking to tech support (JasonC), I re-routed the crank position sensor wire away from the ignition wires which were apparently messing with the electrical signal (Jason also said that the Tec-II has a weird failsafe mode where it apparently runs the engine without really knowing what position it's in)

After a dinner at Mel's with the BAMO guys, the car started fine and showed the correct RPMs, so we headed for the freeway, where I proceeded to drive 45mph this time due to even higher EGTs :( The convoy nicely pulled over for me again, and Matt helped me look into the problem again. Since the RPMs were now fixed, we reset the original map (the non enriched one), and Matt slightly tweaked it. After a quick test drive the car really seemed ok this time, and we were able to finish the drive home.
This was frankly more excitement than I was hoping for, and I'm not quite sure what state the car is in right now, but I'll have John look at it.
Either way, I'm somehow still happy I was at thunderhill with the BAMO crew and the miata, and thank you so much to all the people who helped me and waited for me on the way back.

Moral of the story: if you have a Tec-II, don't leave home without your laptop, a cell phone, and your tech support numbers :)

Anyway, you can browse the pictures here