1 problem fixed now need help with a new one.

[Duke86max]

1986 Vmax
I was having problems with the start button not working figured out I had a 2 wire starter relay that was grounded got that fixed and took the bike for a ride got about a 1/4 mile and it cut off after letting it sit for a minute or two I cranked it back up and rode about a 1/4 mile and it cut off again ended up having to push it back home cause it wouldn't fire again.

When I was riding it the tach dropped and the signal fuse blew. I went out this morning and put a new fuse in it got the neutral light back as well as the fuel pump tried to start it and it would crank but not fire up. I jumped it off and it started, I unhooked the charger and left the bike to warm up it ran for a few minutes then cut off. The signal fuse was blown again:ummm: No neutral light and no fuel pump.

I am wondering if the battery is weak and the charging system not working can that blow out the signal fuse when the fuel pump is trying to run? I know the battery is probably no good as it won't hold a charge but I'm not sure the bike is charging either.

I'm just wondering why the fuse is suddenly blowing and if it can be related to a load that can't be handled???
Thanks
Duke

 

[Duke86max]

Nope way off! Seems to be related to fuel pump.

 

[Redbone]

The fuel pump is blowing the fuses?

 

[Duke86max]

Man I really don't know but pushing this thing is getting real old real quick.

I turn on the key and the fuel pump comes on and does it's thing then shuts off. Neutral light is on hit the button and it fires up( no tach at all) sits and runs for a minute or so and cuts off, neutral light is off and the signal fuse is blown. I have done searches and read various posts where things are sort of like this but the person had to turn on turn signals or the like and that's not the case here. You can just let it idle and it will blow the fuse. Also in the posts I've read it is said that the fuel pump isn't run by this fuse but if it cuts off and you cycle the key off then on with the fuse blown the fuel pump is silent put the new fuse in and turn the key on and the fuel pump comes on.
Duke

 

[rhoke]

Well, to me it sounds similar to the issue you just had. However, now it is grounding somewhere in the signal circuit. Time to track down the gremlin and iron it out.

 

[MaxMidnight]

Agree - you need to establish what is causing the fuse to blow.

The signal fues powers:
Starter circuit cut off relay
Horn
Water temp guage
Neutral, fuel and oil warning lights
Rear brake switch

 

[Duke86max]

Apparently when I taped up the wiring harness when I was finished fixing the other problems I taped something together that should not have been. I untaped the wires that go across the front of the airbox and it cranked up and ran fine with no blown fuse. It's not apparent at a quick glance what it was but I will look when I get up this afternoon.

I still have no tach and the neutral light comes on when I pull in the clutch with the bike in gear???????

If I ever get this electrical sorted out I may be able to ride this thing. LOL
Later
Duke

 

[satariel666]

Time to rebuild You harness completly.Unzip evrything and zip it from a new. Id say dont do that unless You have some electrical skills - better buy another used harness in a case You dont have electical skills. Im sure Sean have some on hand.

I've done complete rebulid about 2 weeks ago, serching the poping gremlins I've started to have on my v-max.
I replaced some wires to thicker ones.

Unfortunetly the harness was not my problem.
But I finaly found the poping problem.

Good luck.

 

[Duke86max]

Well there is no more fuse blowing so I took it for a little ride. Still have no tach even though I have 12v at the grey wire and the brown wire to the back of the tach. The neutral light lights everytime I pull in the clutch going up through the gears.

Went for a putt and got about an 1/8 mile and wouldn't take throttle just bogged then cut off. I tried to restart and it just cranked but wouldn't start. I cycled the key on and off 2 or 3 times and it fired right up turned around and headed home and by the time I got here it cut off again. I pulled the plug for the fuel pump and have 12v to the fuel pump and put on a new fuel filter still the same.
Later
Duke

 

[vmaxcruzer]

Have you checked your safety switches on the side stand and clutch lever? You can bypass them to see if some or all of your problems go away. Its a long shot but easy.

 

[naughtyG]

I agree with Przemek - your best bet is to get another harness from Sean or anyone who has one and replace it.

I had gremlins (my bike could not be turned off) and I'm pretty good with electrics, I unzipped most of my harness and took a good look around and could find nothing wrong.

Replaced the whole harness and it went away. It's not that hard to do actually, a lot of the end stuff stays on the bike and just plugs straight into the main harness.

 

[Duke86max]

I checked the switches and they are working. I dug a little deeper today and found that with the engine running there is no power to the fuel pump.

There are 2 relays one is the big flasher relay and one that on the wiring diagram is called the fuel pump relay. When I first turn the key on the fuel pump comes on and runs for the 5 seconds then the relay clicks and shuts it down. I start the engine and check the voltage at the fuel pump plug and there is nothing.

What I'm wondering is this: Is the relay bad? Or is there something keeping the relay from coming on? As I said before the tach is not working either even though I have 12v at the brown wire and the grey wire on the back of the tach and also 12v to the grey wire that goes to the fuel pump relay and to the vboost control unit.

I had a problem before when the bike was running where I would be riding and all of a sudden the tach would start bouncing then drop to 0 and the bike would shut down. I would pull over and switch it off for a minute or 2 and it would crank up and I was on my way again.
Thanks
Duke

 

[naughtyG]

Again everything you say points to an electrical fault in the wiring harness - some wires are getting fused esp. when hot hence when you pulled over and restarted it would be ok.

Find a new harness, replace it and you'll prolly never look back.. My 2cents, ask Sean.

 

[Duke86max]

No way that I can replace an entire wire harness so if that's what it is I guess I will need to cut my loses Thanks for the help.
Duke

 

[naughtyG]

No way that I can replace an entire wire harness so if that's what it is I guess I will need to cut my loses Thanks for the help.
Duke

Honestly I did it to mine last year and it was way less hassle than I thought!

The harness is just the backbone of the electrics - everything stays in place and plugs into it. You just have to remove a bunch of things to get to it around the front - scoops, carbs, TCi box.

 

[one2dmax]

Hot wire the pump first to see if that solves the problem. If it doesn't then we can go forward from there. If it does we can work on solving it. For some reason I want to say the very early bikes had a resistor inline up near the gauges that goes bad. The pump runs off the timer when you first turn the key on. After that it needs a tach signal to the relay to keep the pump power activated. It might be a simple relay or maybe even the diode block.

I can loan you a few different items to test with. See my parts loaner program in the Morleys Muscle section.

Sean

 

[Duke86max]

The relay is getting 12v via the gray wire from the tach. I have ordered a new relay but I am worried that if something is amiss in the wiring harness it will short out the new relay. I may need to get some assistance from someone who has swapped harnesses and see exactly what needs done.
Thanks
Duke

 

[Duke86max]

Well I got another wiring harness and installed it. Now the neutral light goes off when I put it in gear but the turn signal indicator stays lit still hard to get started and no tach. Still waiting for the new relay to come in but I don't think it will help I am keeping my fingers crossed though. I could live with the signal light staying lit but not the tach. not working.
Later
Duke

 

[Saml01]

Check the state of the wire coming off the fuel pump and then the harness end of it.

This is what the ground look like in mine coming off the pump and inside the wire harness.

 

[one2dmax]

You have the nuetral wire and oil level wire crossed more then likely. Check under the left side cover. The 2 bulleted wires. Swap them around. They aren't color for color like most of the other wires on this bike.

Sean