Privacy guaranteed - Your email is not shared with anyone.

EFI Bonneville not Re-Starting when Hot...

Discussion in 'Mechanical & Technical' started by Burphel, Sep 17, 2012.

  1. Ok, oddball problem here. 2010 Triumph Bonneville T-100 (EFI)

    3 times in the last few weeks my bike has refused to start. All with the engine hot. Hot as in I'd been cruising at 70 for an hour or so (which with a -2t front, means 5k rpm - the Bonnie's redline is 8500). While running, the bike sounds/feels normal. Stopped, killed the engine and did something for a while (unloading at hotel, watering a tree, eating lunch), and it wouldn't start back up. The starter spins, no grinding noises or anything, but no startup either.

    The first time it happened was 2 weeks ago at the hotel. After unpacking, I went to move the bike in front of the office and it wouldn't start as described above. Tried a few times, tried to bump start, but the parking lot was flat. So I went back up to my room and took a shower, got a pizza and soaked in the AC for a while figuring I'd let it cool and if it didn't work after that I'd stop at a dealership I'd spotted on the way into town. Tried again before I went to sleep, about 2 hours later and it started right up. Fired up fine the next morning and ran fine the rest of the way home.

    Also ran fine for running around town.

    Last weekend, went on another road trip. Ran fine Saturday, but on the way home Sunday, it refused to restart after a short pit stop, then again after lunch. Fortunately, the pit stop was at the top of a hill and another biker helped me push start after lunch. After bump starting, the engine again ran just fine. The first two times, there were no check engine lights. The third time, it came on and stayed on for the rest of the day.

    This morning, I started the bike up (normal start) and rode off to a parts store to scan the trouble code. On the way there, the check engine light turned itself off. The OBD scanner read "Crankshaft Position Sensor A Circuit Malfunction."

    My last oil change was <500 miles ago (right before the first road trip where this happened). Mobil1 synthetic 10w40 along with a new Wix filter. The one before that was ~2k miles ago, but I mistakenly got dino oil at the local shop (Motul, forget the weight, but good dino oil, anyway).

    Now I had done a track day on the dino oil (part of the reason I decided to change early). Also, as part of the track day, there was a *lot* of hard engine braking. I wasn't riding the rev limiter around the track, but I was hitting it several times in the course of a lap.

    My suspicion is that I'm dealing with a problem either with gummed up oil from having run dino for a while and switching back, or that something has otherwise fouled up the oil pump/cooler/circulation. I'm guessing/hoping that the crankshaft trouble light thingy is purely related to bump-starting.

    I hate to say it, but I'm really hoping that tipping in some Seafoam and doing an oil change will fix it. As I said, the bike seems to be running perfectly normal, except that when it's hot, sometimes the starter just doesn't work.

    Any ideas? I'm gonna take it to Mac's Cycle in the morning and pick their brains, but I figure I'd try here in the meantime.
  2. Oil ain't got nuttin to do with it.
    Check the sensor as the code tells you to.
    My other thought is a clogged fuel tank vent. (fuel cap)

  3. You most likely have a cracked pickup coil for the crank sensor take it up to Lonnie at Triumph of Tacoma - they can also check for any recall notices that may relate to your bike.
  4. Heh. Tacoma's a bit of a trip for me. Actually found a pretty good dissertation on it over at TriumphRat once I finally put the magic set of words into the search box. Fortunately, it looks like something I can probably handle with a weekend in my old man's shop once I get the parts. Unfortunately, with Triumph, that may not be until winter time.
Similar Threads Forum Date
Flipped stock handlebars on Bonneville Projects Jun 30, 2015
Bonneville Bolt Unveiling 10-25-14 Bellingham Oct 24, 2014
Bonneville Run for Fun Motorcycle Talk Apr 27, 2014
Speed Dreams 2-part documentary-Bonneville Motorcycle Talk Mar 16, 2014
Leaving for Bonneville this morning, Gas Question for OR Motorcycle Talk Sep 5, 2013