Hello and a strange issue

[bmw111]

New forum member, thanks in advance for any help. Reading and lurking for a while, I finally bought a Vulcan last week. Having a strange issue. I'll give my bike information and what I've attempted below.

Today (80 F, humid), I took a quick test ride, felt great, no issues. Did a u-turn, looked down at cluster and both the Coolant Temp and Low Fuel light were on. Gas gauge indicates half tank, I can see lots of gas in tank. Yesterday I did a fan test to see if the fan was working and after idling quite a while the fan came on so I know the fan is working.

Both lights stayed on all the way home. Both lights come on and stay on when I start the bike. Starts and idles OK. When I rev the engine in Neutral, both the Coolant Temp and Low Fuel light flicker/waver and vary in intensity.

Here's what I did after searching online -- basically checked/cleaned/applied dielectric grease to all electrical connections listed below:

• Clean the throttle body throats
• Check/tighten battery leads
• Remove right upper side cover, apply dielectric grease to starter relay, check/clean/grease all relay connections and oil pressure light delay unit connection
• Under seat, check/clean black/yellow wire connected to negative post/harness, bike tip over connector check/clean
• Open and check/clean/dielectric grease control switch housings connections Including ON/OFF switch, clutch switch
• Added Seafoam to tank
• Cleaned out coolant reserve tank due to gunk around hose at bottom that runs to the system, filled reserve tank with fresh coolant (did not check radiator)

The only issue I found was the Starter relay switch connector was VERY corroded. I cleaned it, applied dielectric grease.

Yesterday after a ride with no issues I did the following, to be thorough in my checking/cleaning:

• Opened up ignition/key switch, check/clean/dielectric grease (then crawled around on garage floor until I found those **** ball bearings that flew out of the housing)
• Removed left engine side cover, check/clean dielectric grease, side stand switch connection, Neutral switch connections, all plug/connections under left side cover I could access including reg/rec connectors

Any ideas about the Low Fuel Level and Coolant Temp lights coming on at the same time? Just seems a strange combination of warning lights to come on simultaneously. Doesn't make sense how they would be tied together, and seems unlikely they would both occur at the exact same time if they were different issues.

[Tamej]

With a new to you motorcycle, I would pull the tank. flush the coolant with new, and test the thermostat to make sure it was opening. The bike has been sitting and the thermostat maybe stuck(little or no coolant flowing). You could also check the hoses and tighten the hose clamps. Replace the old vacuum hoses too.
The low fuel light might be on because of low fuel. Mine comes on with 1.5 gallons left.

As Peg replied, disconnect the PCIII while the tank is off. Early, non USB version PCIII could have issues.

[Peg]

You could try bypassing the PCIII to see if that makes any difference? They've been known to go bad & cause strange issues. Certainly check it's wiring. If any of the joins have corroded, or the earth wire isn't a good connection, it can cause problems.

[BrokeAss]

How about the frame ground? I see you checked battery leads, but both ends of each?

[bmw111]

Thank you for the quick replies. I've got a couple new things to add to my growing list of things I've checked or have to check. PCIII bypass, frame ground (duh, why didn't I think of that?), and thermostat. I've been so busy opening and cleaning electrical connections I seem to miss simple things.


Just a few minutes ago I did the following -- check/clean/dielectric greased the ECU connections, the gauge/cluster connectors. I will pick up some coolant tomorrow and do the tank removal and coolant flush.


Didn't know that about the early PCIII models. I'll look more into that aspect.


Appreciate the help.

[denny 606]

Check the wire harnes near the gas tank where it runs along top of the frame, more Than one of us have found wires shorting to ground fro rubbing against the tank/frame. A little electrical tape and a couple of zip ties Will keep,them from harm tooo

[bmw111]

Thanks for the good tips. I'll update this thread with results.

[bmw111]

Update.


After doing these -- check/clean/dielectric greased the ECU connections, the gauge/cluster connectors (in addition to all the original connections) -- the warning lights went away. I've been taking it on short rides for the last few days and no issues. Until today. I decided to take it on a longer ride, couple of hours, and all was well until I was coming back home and accelerated at full throttle onto the highway. The same two lights (low fuel level and coolant temp) started flickering. I backed off the throttle and they went away until I was just a few minutes from home (just cruising) and they they came back on and stayed on when I was downshifting.


So now I'm going to remove the tank and check/clean the connectors and wiring under there as well as do the coolant flush. I still think it's bizarre that these two lights -- and only these two -- flicker and come on identically, like they are on the same circuit or connected somehow.

[redjay]

Did the stalling issue go away ?
How old is the battery ?

[MrMikey]

When I rev the engine in Neutral, both the Coolant Temp and Low Fuel light flicker/waver and vary in intensity

Wondering if it's charging? When you rev it up and they start flickering it's what makes me wonder as you need more juice to keep the engine going. Check for 70VAC± from the stator and over 14VDC± out of the RR. Just a random thought popped into my head.......M

[bmw111]

No stalling.
The battery is new as of April this year.



So after I updated the thread today I went out to the garage ready to remove the tank. On a hunch, I kept the ignition ON while I started removing items, to see if anything I removed or touched would make the lights disappear since it sure seemed like an electrical connection issue. When I got to the battery to disconnect the negative lead I saw the lights flicker. So I started moving stuff around, pushing, poking and it turns out the main DFI fuse connection (which I had checked before to make sure there was no obvious corrosion) would make the lights turn on and off when I moved it around. This was kind of an "aha" moment because every time I would cycle the key when these lights were on, the fuel pump "priming" sound didn't seem right. Sounded like it was "struggling" or took longer than normal. And could a bad connection there have caused the stalling issue, as well?


So I cleaned the connectors and fuse, applied dielectric grease. I opened up the rubber tubing that the two fuse connector wires were in as far as I could and the wiring up until it joined the harness was in perfect shape. After I cleaned and applied grease I couldn't get the lights to light up no matter what I did with the wiring and connector, and the fuel pump primed like normal.



I buttoned it up and went for a test ride. This time the low fuel light did come on (by itself), but as expected when the gauge was getting close to the Empty mark.


Seems the thorough connector cleaning did the trick.