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Keen to hear thoughts on mechanical issue on the road...


Gmc28

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Here we go...

”red” (what i’ll Call this silver/red 02 lemans) decided to quit running while cruising down a tasty back road north of Tucumcari.  The cool road is another story, but of course it happened as I came into the most remote part of the road, and had no cell service.  Coasted to a little driveway area to troubleshoot.  

Symptoms: while loping along in 6th at about 70mph, she just all of a sudden felt “gutless” for little bit... still running and going, but twisting throttle didn’t do much. That went on for 5-ish seconds, then got worse, then it faltered, and again, then started to decelerate whether I wanted it to or not, and I pulled in clutch to let her coast, and she sputtered, then quit.  Toward bottom of hill I released the clutch to bump start, and it did, but sputtered more and quit.

what I did:  what I did didn’t fix it, I think the brutal wind that I’d been cursing probably helped cool things down  quicker, though that’s just a stab.  Turn key and hear the fuel pump and solenoid.  But, it sound anemic.  Little unsure about that, as a solenoid should either work or not, and the wind made it really hard to hear, but I swear the click and the hum from the fuel pump was weak.  In fact, the pump sort of squeaked.  

Pulled the seat, checked fuses just because, then verified the fuel pup relay was clicking. It was, but changed it anyway.  Started, ran rough, and I shut her down.  Changes the ecu solenoid just because I had several solenoids and wanted to do something while thinking about what’s going on.  Plenty of gas.  In hindsight I did not pop the fuel cap to see if there was any suction, as actually the bike behavior would be consistent with a clogged charcoal cannister (just noticed it back there... thought it had been removed, but no).  Vacuum build up from bad tank venting could cause that sort of slow flame-out, then allow it to run fine after waiting a bit.

i had just come up a tasty, steep, twisty road carved into the the face of a mesa-cliff thing, with 25mph posted speeds and me of course not behaving.  I was not going easy on red, but neither was I flogging her.  Data point perhaps.  And I pulled over for a 1 min photo op and left her running, and it was hot out.  Another data point perhaps. 

After 15-ish mins of futsin’ around, changing those relays, things cooling off, I figured I’d give it another go and see if I could reach top of next hill to get cell reception.  She ran fine , and I rode her the next 20 mins in deafening headwinds (32mph winds per the local airport Wx  info) to the gas station and cell reception, where I am now.  

Topping off then, heading to Santa Fe, about half hour I think, and hope it goes well.  Eager to hear thoughts on what u think my gremlin is.

cheers

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Adventure! Sounds of intermittent fuel starvation from.... idk, stressed pump, mashed potatoes in the lower reaches of the fuel tank? what was fuel level when this happened? Just shite gas on the last fill up? throw some fuel additive in just for kicks. WAS there vacuum in the tank when you popped the lid?

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Arrived without further drama in Santa Fe. Adding fermented liquid to the throttle operator now...

she ran basically flawless on the freeway.  75mph limit, so easy to do 85, and she purred the whole time, about 56 miles worth.  Entering downtown went through the series of traffic lights, and she idles poorly.  Odd.  Perhaps just a distraction, or maybe related.  I’m thinking distraction. 

Manual fuel cock, if I recall the details of that.... there’s a nickel sized metal turn-knob just under the aft left side of tank which presumably is the fuel petcock.  What’s the tell-tale of a manual vs electric... a wire?

bad fuel a possibility.  Added fresh high octane at last stop, but it was only half empty, so could take a while to work that out.  Maybe some additive, as suggested.

cant yet prove yay or nay on suction/vacuum in tank.  Was ready to pop fuel cap if she started to sputter again, but she didn’t.  And I’m truly about deaf now from the brutal wind onslaught.  I left my earplugs out after she quit, thinking I’d be able to better hear any telltale signs, but instead the road straight into that damn 30+mph gusty wind, which rag-dolled me around and shrieked in my ears to where I feel like I just left a Metallica concert, minus the good parts...

do failing fuel pumps on these exhibit a pattern of faultering before dying?

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More likely a failing Relay#5 or Ignition Switch wiring. What are you sticking in there for relays?

Also, must be concerned for fuel filter and air filter. These often get neglected on V11 since they are "tank off" maintenance. . .

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Replaced the #5 fuel pump relay.  With the old relay it still gave me a fuel pump “click”, but maybe it was failing, and the new one (Bosch, because it was there in the kit and readily available, but I have the Omrons in my kit as well) fixed it.   I’d love to believe that is the case... hate not having a smoking gun.

fuel and air filter are indeed a troubling possibility.

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I’ll have to double check docc, but I believe that’s exactly what i have.  But the issue with the brand & model is more about longevity, and not so much about being junk out of the box?  In other words, i assume that if the Bosch I just put in works, then it works, since it’s a relay, and then it’s just a matter of how long it will last?

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So, this is more about amperage (current) ratings. The Bosch are good relays. I use them to blow my (FIAMM) horns.

They just are not rated for High Current (Relay#5).

If you are riding an early V11, the front two relays are needy, as well.

 

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Roger-roger.

this is an 02 lemans, so not sure if that qualifies as an early V11?

tomorrow morning i’ll Seek out some fuel additive (maybe sea foam) to clean up some possible bad fuel,  and check the charcoal cannister lines.  Any quick guidance on which lines do what on the cannister?  I’m comfortable with how they’re usually plumbed on other bikes but haven’t looked at the v11 setup.  Assuming I can vent the one line to atmosphere and leave the other two or plug them?

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Ya, in theory I can just unplug it all, and keep the lines open for now, but hoping to avoid tracing each line to figure out which is which, till I get home, if possible.  Maybe it’ll be Easy. Just assumed that since it’s in back it may not be immediately Obvious where each line routes.

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Any vacuum leaks in that vapor-recovery-mess can be addressed with a couple tight fitting caps at the intake taps. Leave the rest just hanging for now . . .

Stab in your Best Relays and tighten the battery terminals.  And service that main ground behind the seat lock, if you can get to it. :luigi:

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Thanks all for thoughts so far.  I’m thinking fueling issue, whether pump, relay (for pump), vacuum from clogged charcoal cannister, or bad fuel is hard to say.  New relay in place, next tank of fuel and additive to address bad fuel, and maybe mess with the charcoal can lines and we’ll be off for Durango tomorrow.

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