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-   -   Bike Start w/o Button Presses (https://www.vn750.com/forum/19-electrical/79922-bike-start-w-o-button-presses.html)

Scubawerx 12-31-2015 04:35 PM

Bike Start w/o Button Presses
 
My '03 750 tries to start after I turn the power 'ON' but before I press the start button. Quick suggestions?

Vulcan2000 12-31-2015 05:59 PM

Quote:

Originally Posted by Scubawerx (Post 1028978)
My '03 750 tries to start after I turn the power 'ON' but before I press the start button. Quick suggestions?

Not sure if the start button can be taken apart and the contacts cleaned. If possible I would use a small file and contact cleaner.

Spockster 12-31-2015 07:05 PM

Not sure if this would cure it, but The Two Wire Mod bypasses the relay in the JB that can be a problem with the start button. Also cures or prevents other problems. Look for the sticky post in Electrical.

Scubawerx 12-31-2015 10:25 PM

Will do, thanks.

Scubawerx 01-01-2016 03:56 PM

Little more digging found these issues.
1. Power always on to the low voltage feeding solenoid when key is turned on.
2. No power to tail light (as should be there if the key is switched on) but light does come on when I press the "Start" button.
And again, if the switch is turned on, the engine immediately starts to turn over. So something is switched.
I think the ECM may be bad, but would like to test it prior to ordering a replacement. I can't find directions for test the unit.

michiganteddybear 01-01-2016 05:22 PM

there is no 'ecm' per say on these bikes.. there is a junction box (where the relays and fuses are) and the ignition module (which only controls the ign and timing, NOTHING else).

its sounding like you have a shorted relay (or other short) inside the junction box. they are known to cause a multitude of weird and or strange issues when they start acting up.

Yes, you can take the start button apart to check/clean it.. in fact its a totally 'open' switch.

im trying to dig thru my memory on whether or not there is a constant +12v on one side of the solenoid.. I want to say there is not a constant 12v on it.

the 2 wire bypass mentioned previously will bypass the clutch switch and neutral switch, which means it will start in gear. BUT it bypasses a known problem in the junction box that causes intermittant cranking when the start button is pressed.

a stuck solenoid can also cause the issue your having..

and last, but definatly NOT least, is the ign switch itself.. it can cause strange shait when its dirty as well.

Spockster 01-01-2016 08:14 PM

You can check to see if the bypass will help by removing the two wires from the 10-pin plug at the JB, jumper them together, then see if the phantom cranking is gone. If it goes away, proceed with the Two Wire Mod.

Hey mtb, check your inbox ;)

slimvulcanrider 01-01-2016 11:00 PM

Quote:

Originally Posted by Scubawerx (Post 1029178)
Little more digging found these issues.
1. Power always on to the low voltage feeding solenoid when key is turned on.
2. No power to tail light (as should be there if the key is switched on) but light does come on when I press the "Start" button.
And again, if the switch is turned on, the engine immediately starts to turn over. So something is switched.

I think the ECM may be bad, but would like to test it prior to ordering a replacement. I can't find directions for test the unit.

Start button is constantly making contact, or short in the start button circuit near the steering neck connectors.

The taillight doesn't come on until after the stater energizes the headlight relay inside the fuse box, so the engine must be running

When you say the ECM, I am prone to believe you are talking about the Ignition Control Box [ICB]. If the ICB were o fail, it woulnd't cause the starter solenoid to be engaged with the key on.
first thing I would do is take a part the Starter switch, and with the switch apart try turning on the ignition (ready to shut it right back to the off position if the engine starts to crank). If the engine doesn't crank go to step 1: If not finish step A:
A: The starter button is a very simple switch to take a part and clean. just unbolt the switch housing from the handlebars and its pretty self explanatory to get to the stater button itself. Once you get to the starter button, pull out the little spring and clean it with brake cleaner, then apply liberal amounts of graphite to the spring where it resides inside the plastic button itself. on the contact side of the spring dab on a small amount of dielectric grease. look for carbon scoring on the switch contacts and use a piece of steel wool to shine the copper back to a shiny copper color.
Reasemble the switch and housing... retest.. If bike still tries to start after turning on the ignition switch with out the use of the starter button, move on to step 1:

1: Check the connectors under the clutch side neck cover for looseness, corrosion, broken connector, and/or possible shorts to ground. Unplug the 6 pin connector and test for power on the Blackd and Red wires (main harness side of the connector). If you have power on either wire, then you have a faulty Starter relay inside the Fuse (junction) Box and needs to be fix/replaced.
If no power present, every thing this far is good. Reconnect the 6 pin connector and go to step 2.

2: check the power coming out of the Fuse Box on the large white wire with the ignition switch off. (should be power). next check for power coming out of the ignition switch on the Yellow wire (should not have power). If you have power on the last test, you have a faulty Fuse Box and have to repair or replace the fuse box.

Scubawerx 01-02-2016 10:26 AM

I found the issue last night. When reinstalling the new wiring harness, I wrongly connected two of the connectors at the steering neck. Once corrected, everything works as was designed.


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