Tuesday, May 31, 2016

Oh Crud, I Broke a Stud

It's been a busy month of moving and trying to wrestle a clutch into T's Subaru, so I haven't had many adventures worth documenting. Since T's Subbie is on ramps with a transmission sitting in front of it, he is driving my car, so I've been daily-driving the bus. It's really been great, with a few little hassles. Today is about those hassles.

Shake Much? Funky Clutch
Have you ever been pulling away from a stoplight and a semi-truck next to you starts shaking like there's no tomorrow as it pulls away from dead stop? That happens when something has been introduced onto the clutch or flywheel or pressure plate causing the clutch to not completely grab correctly. When I last pulled out the transmission (Transaxle Re-Assembled) in the Fall of 2014 I must not have completely cleaned either the flywheel or the pressure plate. MAybe I got a greasy finger on the clutch disk. The bus shudders as I pull away from dead stop now.. especially when it's cold. I'll probably have premature wear-out on my stage-one clutch as a result. Grr. The shaking, though, brings about it's own troubles.

No Power Rush Hour
I was on my way home from work a couple of weeks ago when suddenly and unexpectedly the engine stopped running. Turning the key had no effect. Since I was coasting to a stop at a pretty major intersection, I let the bus roll into the bike/breakdown lane and slipped out the slider door. I popped open the rear gate and looked at the wiring that ties my ignition key to the TDI harness. Knowing that there was probably an issue there, I pulled the pins out of the TDI ignition plug and popped in the original plastic plug. The engine fired up with the turn of a screwdriver, demonstrating that my remote starter was working. Back in business, I climbed back into the driver seat and motored around the corner, only to have the ECU drop into "limp mode". I fixed the "no power" by re-wiring the relays and wiring around the TDI harness ignition switch while taking a break from the moving fun. The root cause was one of the wires had freed itself from what it was plugged into. I blame the shaking mentioned above.

The computer needs to get a clean signal from the drive-by-wire accelerator potentiometer (usually called a "pot"). In the bus, this pot is attached to the underside of the cab and controlled by the stock accelerator pedal. The wire bundle running back to the computer is probably 15 feet long. In the original donor car, the wire bundle was about 4 inches long. If you add all that extra wire, there is additional resistance which can get in the way of that clean signal. When this happens, the computer drops into "limp mode", bringing the engine with it. Limp mode pins the engine speed at 1200RPM. While frustrating, the limp mode can be cleared simply by shutting off and restarting the engine. When this happened in the Rush Hour example above, I had to get off the road to shut down and restart because the "ignition" was 10 feet behind the driver seat.

4 out of 5 Recommended
Last March, I posted about getting some new wheels for the bus. They look great, but they are thicker than the stock wheels. Since the tires I had on the bus were 12 years old, I couldn't safely go back to the old tires, but the studs don't stick out far enough for the lug nut to get all the way on with stud sticking out the other end of the nut. I pulled a classic prior-owner-worthy fail in not double-checking the 94 foot-pound torque on the nuts, and then threw 2 nuts off the rear right wheel before noticing a "wub wub wub" noise. I pulled a lug nut from the other rear wheel to get 4-a-side, but one of the studs broke off and won't thread a nut anymore. The internet is not consistent about driving on 4 nuts when the vehicle delivered with 5. I've been doing it for a little while now, and I check my torque while looking for fluid drips.

Some of these hassles represent work I need to perform. Okay, most of them do. I have replacement wheel hubs on the way from Ken at TheBusCo and I already have the over-length studs I mentioned in my post about wheels (see Wheels, Studs, Chrome and Backspace) so I'm going to start preparing for that work. It could mushroom into more things since the rear suspension and brakes haven't gotten the deserved love in a while.

That's it for now. I'm in the process of getting T's car back together and him through high school graduation before I tear into solving some of the bus' issues. Thanks, as always, for following along..

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