DOTR ... Dead On The Road. HELP

[aviationfred]

Check the rear break switch. The lock nut has a tendency to work loose. I have seen this be the cause of a short in the brake switch wires. This switch IS on the turn signal fuse circuit.


Fred

[timleslie1957]

Will do ... I will have a lot more time over the weekend.  Leaves are changing, gotta get her running again!  I feel like I lost a family member!   

[Stuarto49]

You are certainly on the right track.  If you found a blown fuse, and it blew again, you will find a short somewhere in the system.  Study the wiring diagram in the shop manual so at least you will know what devices are fed by that 15A fuse.  There are only a few devices on that feed.  One of them is a dead short to ground.   

Stuart

[ribbert]

Anyone that tinkers with cars or bikes should have one of these, makes finding shorts and broken connections a cinch. You can check the continuity of all electrical connections and test the integrity of earths at any point over their length in minutes. To find a short, attach the clip end to earth and start probing live wires (with no power to them) and any wire that lights up the tester is shorting to earth. No more scratching around for days swapping bits out hoping to get lucky.



It's a self (battery) powered continuity tester, sort of like a reverse test light. It makes homing in on a short a few minutes work, particularly on a bike where everything is accessible.

Way better for this sort of work than a multi meter and they are only $15-$20

Noel

[timleslie1957]

You are certainly on the right track.  If you found a blown fuse, and it blew again, you will find a short somewhere in the system.  Study the wiring diagram in the shop manual so at least you will know what devices are fed by that 15A fuse.  There are only a few devices on that feed.  One of them is a dead short to ground.   

Stuart

Funny you said that about the manual.  I have it here at work today and was just getting ready to take a break and take a "squint" at it.  I was an Electronics Warfare Specialist in the Navy so I know my way around schematics and such.  I also know shorts and dead shorts are difficult, but the wiring seems fairly accessible.  I just need some quality time (early in morning before my boys awaken) to troubleshoot now.  Lessons relearned a kazillion times now - you can't tell a fuse is blown simply by looking at it.  Have you ever tried the "glow" fuses? 

Stuart, as usual, thanks for your time.  I get lazy and look for shortcuts, and this forum is INCREDIBLE so I data mined here since I have access to PCs all day long.  I really appreciate your help.  I absolutely love this bike.  Never rode anything I enjoyed more.  And I have ridden a lot of them.  A friend is pushing me to buy a newer model one day, and I am thinking on five year plan to get another Yamaha but I am not selling this one.  Incredible machinery supported by these guys here so well.  Incredible!

[timleslie1957]

Anyone that tinkers with cars or bikes should have one of these, makes finding shorts and broken connections a cinch. You can check the continuity of all electrical connections and test the integrity of earths at any point over their length in minutes. To find a short, attach the clip end to earth and start probing live wires (with no power to them) and any wire that lights up the tester is shorting to earth. No more scratching around for days swapping bits out hoping to get lucky.



It's a self (battery) powered continuity tester, sort of like a reverse test light. It makes homing in on a short a few minutes work, particularly on a bike where everything is accessible.

Way better for this sort of work than a multi meter and they are only $15-$20

Noel

Thanks Noel!  You know, I use a DVM and you are so right.  I use my friends continuity tester but should indeed buy my own.  Stopping by the store this afternoon on the way home from work!  I'm sure my bud will be relieved as well!  LOL

[timleslie1957]

Okay so the schematics in Haynes for my year bike has the solid brown feeding:

- rear brake light sw
- front brake light sw
- horn
- fuel gauge which jumps to: fuel warning light, neutral, oil level.
- E Regulator feeds base of fuse switches to headlight, ignition and signal.  The bike WILL start but bogs down soon unless you feed it entire choke, then revs steady about 2.5k to 4k RPM.  All listed items are inop.

So troubleshooting, I guess I should T/S destination to source (from say brake sw to fuse) etc until I find short.  The only part that has me confused is the feed from the regulator.  I need to trace the DVM back as well and I will assume it was hooked into the brown as well since it is dead also.  Sound reasonable?

[FJ_Hooligan]

I would start where any aftermarket equipment (like a voltmeter) was spliced into the brown wire.  Please don't take that personally Stuart!

Look for places where the harness rubs against the frame.  I know I've had trouble with my horn wires falling off the horn tabs.  The small section of the harness is subject to a lot of flexing.

What's a E Regulator?

I thought the carb issue was due to the fuel pump not working because it's on this circuit?  The choke supplies more fuel, but that fuel comes from the same float bowl.  Is this related to the electrical problem or a separate issue?

[Pat Conlon]

A ground fault in the horn wires is common. The 2 wires are hot, only grounded by the horn button.
The wires can rub against the steering neck every time you turn the forks.

For owners of the '88+ fuel pump FJ's it's important to learn how to splice your fuel line together to by pass the fuel pump in the rare occurrence when the fuel pump fails. This knowledge will get you home.

[timleslie1957]

I would start where any aftermarket equipment (like a voltmeter) was spliced into the brown wire.  Please don't take that personally Stuart!

Look for places where the harness rubs against the frame.  I know I've had trouble with my horn wires falling off the horn tabs.  The small section of the harness is subject to a lot of flexing.

What's a E Regulator

I thought the carb issue was due to the fuel pump not working because it's on this circuit?  The choke supplies more fuel, but that fuel comes from the same float bowl.  Is this related to the electrical problem or a separate issue?

E is voltage symbol ... Sorry.  Old habits.  Duuno about fuel pump.  All I know is it will nokt run without choke on full..  Did not see the brown feeding the pump but will remember to run that down.  Thanks.

[timleslie1957]

The bike would not run when this happened as in it died.  I do not know if separate issue.  Laid up all weekend with bronchitis.  Going to take a cursory look in a few minutes before daylight runs out.  Going to look at schematic again to see how pump ties in.

[timleslie1957]

Isolates to bundle at battery at connection block to DVM.  Should be simple rework.  I am going to search some heavy duty well insulated connector blocks and redo everything around battery then point to point to horns and such this winter.

[timleslie1957]

And yes ... The fuel pump is indeed on the signal fuse hot.  Just checked Haynes again.  I was looking at fuel reserve which is not on same fuse.  Fun time learning this bike.  Just took a short ride after bolstering up the connections to dvm and lights.  Did perfectly.  Smiling again!