Friday, July 29, 2016

Another Tow

In my last post, I lamented a little bit at the end about dropping into a version of limp mode (1200 rpm symptom) and sporadic misses. Today's post covers the start of what I did to resolve it. I split it into two posts because I tend to get wordy.

Muir's Divination
If you haven't read How to Keep Your Volkswagen Alive by John Muir, you absolutely should, even if you don't own an old Volksie. His tone and humor can still be felt on some VW boards and the YahooGroup member mail. Somewhere in his book, he writes about the promises we make to our cars of future repairs, if he-she-it just gets us home. Old VW's seem to have a soul, and they respond to those promises (sometimes) with safe passage home. The return trip from 4Peaks was one of those moments. About the time I was re-starting the engine to reset the engine from the 1200 RPM symptom every 50 feet, I promised Hapy that I'd get him fixed before I drove him again. He just needed to get us home. Like a good soldier, Hapy settled down and took us home with little trouble. Since my usual sled (Flash, the TDI Jetta) was still being driven by my 18 year old son while he completed the repair on his car (subaru clutch job), I reneg'd on my promise to Hapy and drove him to work the next day. It was under 3 miles, but it was still breaking the promise. Hapy let me know how he felt when I went to leave work at the end of the day.

Repo-Style Tow
Hapy would start and drop immediately into the 1200 RPM symptom from the first start after work. By the way, I'm not calling it limp mode anymore since "limp mode" is actually a different condition. I was able to get positioned in a parking lot that allowed for a tow truck to get at the bus while also in the shade (90*+ day), and waited for AAA to send the usual flatbed. What arrived instead was what I'd call a repo-truck. It was small and had a relatively non-descript towing rig attached to the rear. As it pulled in, the tow rig looked like a large iron cross jutting up from his rear bumper. When lowered, the cross would abut against whatever tires it could and then latch around from the other side. All told, this truck was able to snatch a car in under a minute. The driver slapped on the safety straps, and magnetic marker lights and we were on our way inside 5 minutes after he arrived.

On the route home, the driver shared that this was his first boost of the day and that he was heading over to the Hillsboro Hops field for opening day next. Apparently, lots of folks park illegally at that park, so he spends a few hours at every game snatching illegal parkers and hauling them a few miles away to impound. Not exactly my definition of a dream job. He was able to drop Hapy in the "fixit spot" at the end of our long driveway, though (see picture).

Un-Rat's Nesting
in process
Before
My friend Justin will probably be the first to agree that the wiring I didn't do when I did the TDI install was long overdue for a cleanup. I did what Agile tells us to do: the very minimum to achieve the desired end state. When conditions indicate that things need to be redone, do it then. Well, with the 1200 RPM symptom and the other codes getting thrown, I think it was time. Or past time. So, circuit by circuit, I removed unnecessary wiring. I started with plugs in the rat's nest that weren't plugged into anything and tracing those wires to their termination at the fuse box, ECU or a junction. Then, I pulled the unneeded plugs and wires from within the engine bay the same way. This required significant unwrapping of cables and subsequent re-wrapping for cleanliness. Last, I dug into the fuse box. This last step could have been my first. By verifying circuits at the fuse against the fuse diagram in the Bentley, I eliminated more wire than I retained. In the process, I discovered a possible root cause: I had one main ground, and it had started to shake loose. By removing so much wire, I was able to reduce how many brown wires connected into that ground as well. The end result looks much better, but the relay frames and the fuse box still need to be attached to the body. And, the 1200 RPM symptom didn't go away. Drat.

I decided that the cause of the 1200 RPM symptom wasn't in the wiring nearest the computer. So, it must be the wiring or the potentiometer at the pedal. In the next post, I'll dig into what I found and how I fixed it.

As always, thanks for following along..
discards

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