Bike used to shut off randomly, now has MAJOR grounding problems

[styran]

02 VFR ABS, recently in an accident. main wiring harness replaced

 

The bike will randomly completely lose power momentarily. Everything will shut off, including the dash and motor. When the dash powers back on, the clock resets and the speedo resets to KMH.

We measured 14 volts charging a couple days ago.

Replacing the battery did not fix the issue.

 

Now, after a random shutoff, the dash will light up but the bike will no longer start. It feels like there is not enough voltage to turn the starter.

Measuring the voltage with key off had 12.2 volts

with key on and engine off measured at 11.5 volts

bike did not start and did not crank fully

 

What could be the issue here?

 

[Grum]

No Clock power and resetting is a definite sign of Main Fuse A 30amp power loss, located in the Starter Relay, it will also kill power to the Engine Stop Relay coil = Dead Engine, and power for the Starter Relay coil = No Starter Cranking.

 

Further info - Loss of Clock backup power and it resetting also confirms that the fault can't be an Ignition Switch problem, as backup power is Not switched through the Ignition Switch.

 

Check the Red plug at the Starter Relay. Check for any sign of heat stressed wires and burnt spade connections for the Red wire. Check the fuse and its legs for any signs of heat stress or poor/loose connections.

 

Even though you have replaced the battery it still could be an issue. What does the battery voltage drop to as you attempt to start the engine?  Is your replacement battery a good quality item or Chinese cheapy? I've heard of a couple of new battery scenarios that were down on capacity straight out of the box, and not able to hold a charge, it may have been sitting on the store shelf for too long!

 

Let's know how you get on, good luck.

 

[styran]

6 hours ago, Grum said:

No Clock power and resetting is a definite sign of Main Fuse A 30amp power loss, located in the Starter Relay, it will also kill power to the Engine Stop Relay coil = Dead Engine, and power for the Starter Relay coil = No Starter Cranking.

 

Further info - Loss of Clock backup power and it resetting also confirms that the fault can't be an Ignition Switch problem, as backup power is Not switched through the Ignition Switch.

 

Check the Red plug at the Starter Relay. Check for any sign of heat stressed wires and burnt spade connections for the Red wire. Check the fuse and its legs for any signs of heat stress or poor/loose connections.

 

Even though you have replaced the battery it still could be an issue. What does the battery voltage drop to as you attempt to start the engine?  Is your replacement battery a good quality item or Chinese cheapy? I've heard of a couple of new battery scenarios that were down on capacity straight out of the box, and not able to hold a charge, it may have been sitting on the store shelf for too long!

 

Let's know how you get on, good luck.

 

Battery still has good voltage. 12.8V with everything off.

the problem is very intermittent. the bike currently cranks and starts up with no issues, at least right now.

ended up returning the new Yusasa YTZ12S battery and put the old battery back in.

 

main fuse A seemed in okay condition.

 

the red connector going to the starter relay had a hole much bigger than your picutre.

Could that cause the problem?

 

the old wiring harness has the red connector in good condition so I can swap them out.

 

 

 

ALSO, where did you get that wiring diagram with the colors? The one in the shop manual is black and white and a pain to look at.

[Grum]

That is definitely heat stressed, the Red wire has turned brown and the red plug has melted, a hot and high resistance joint. Think you've found the fault!

 

The Red wire will need cutting back to good unheated copper and new spade connector fitted.

Its not essential to replace the relay coil spade connectors but if you can, then just do it.

 

Replace the red plug with these high quality tin spade connectors, sorry can't remember the web site, just do a Google on Starter Relay Plug replacements should find them. Make sure the Red Wire male spade in the Relay isn't burnt or corroded.

 

You could also try the wiring mod shown using the additional spare spade connector to the Main Fuse to share the electrical load, splicing an additional wire into the main Red wire.

 

Some OxGard on these conections will also help.

 

The coloured drawing is just a section from the 5gen Hi Res downloadable drawing from the forum. Starting circuit and wiring is the same as 6gen.

 

[styran]

20 hours ago, Grum said:

That is definitely heat stressed, the Red wire has turned brown and the red plug has melted, a hot and high resistance joint. Think you've found the fault!

 

The Red wire will need cutting back to good unheated copper and new spade connector fitted.

Its not essential to replace the relay coil spade connectors but if you can, then just do it.

 

Replace the red plug with these high quality tin spade connectors, sorry can't remember the web site, just do a Google on Starter Relay Plug replacements should find them. Make sure the Red Wire male spade in the Relay isn't burnt or corroded.

 

You could also try the wiring mod shown using the additional spare spade connector to the Main Fuse to share the electrical load, splicing an additional wire into the main Red wire.

 

Some OxGard on these conections will also help.

 

The coloured drawing is just a section from the 5gen Hi Res downloadable drawing from the forum. Starting circuit and wiring is the same as 6gen.

 

Is this good?

 

https://www.amazon.com/FLYPIG-Starter-Solenoid-Connector-CBR1100XX/dp/B06XC7KY6S

 

I'm not sure if it has tin spade connectors.

Will definitely splice the full red wire

[styran]

@Grum

We added an extra power wire to the connector and replaced the burnt spade with the spade from an old main harness. That did not solve the problem.

The bike no longer starts now. Turning the key will cause some intense flickering and erroneousness readings for speed on the dash.

The bike will no longer start as well.

Additionally, the bike starts leaking fuel out of the exhaust headers onto the ground. Disconnecting the FI harness solved that issue.

With a power probe we found weak battery voltage on all parts of the frame (which should be ground) and EVERY wiring harness ground wires.

Grounds near gas tank hinge were inspected and in good condition.

 

We've isolated the problem to the "START, BANK ANGLE SENSOR FUSE" circuit.

The frame is powered by the weak battery voltage when the key is on and the fuse mention above is in.

Having the engine stop relay plugged in, bank angle sensor jumpered, killswitch run,  with key on will cause power to be sent through the frame grounds.

Without the relay the frame grounds and wire grounds normally with key on.

Plugging in the dash with key on will also cause the same issue as the relay with key on. Very strange. Either the dash or the engine stop relay being plugged in will energize all the grounds.

Swapping relays also had the same bad results.

We believe the issues is involved with the front subharness (big grey and blue connectors).

We have inspected the yellow grounding block on the front subharness and it is in good shape with no obvious burn marks.

 

To avoid frying expensive computers, we have removed the ABS module, pulled all ABS fuses, removed the ECM, removed main fuse B. All headlight fuses and connectors have been pulled as well.

We found that the tail license plate light was energizing the grounds at first, after unplugging it, the problem still persists.

Also, the issues still persisted with the front subharness replaced with an old one that was involved in the accident.

Any ideas?

 

[Grum]

Holy Cow!! You seem to have gone badly backwards from just replacing the Starter Relay plug! Are you confident the wires in the plug ARE going to the correct connections at the Starter Relay?

1 hour ago, styran said:

The bike will no longer start as well.

Additionally, the bike starts leaking fuel out of the exhaust headers onto the ground.

Assume you're saying it cranks over but doesn't start? Is that correct.

Cranking excessively trying to start it has probably caused flooding.

Might require you to go through the purge process of throttle Fully open while cranking, shuts off injectors purging cylinders.

1 hour ago, styran said:

With a power probe we found weak battery voltage on all parts of the frame (which should be ground) and EVERY wiring harness ground wires.

So if your battery voltage is say 12.5v and you leave your positive meter lead at the battery and you probe any ground point or wire and you're seeing noticeably lower than the 12.5v. This would point to either a bad Negative connection at the Battery or poor main Ground to frame or engine.

 

1 hour ago, styran said:

We've isolated the problem to the "START, BANK ANGLE SENSOR FUSE" circuit.

The frame is powered by the weak battery voltage when the key is on and the fuse mention above is in

Your messing with my head referring to frame ground power! If you have a meter lead on the Battery Neg terminal And you probe any Ground with the other lead AND you measure a voltage, then the Ground is Not properly Grounded.

Any suspicion of the BAS. For test purposes you can easily unplug it and bypass it to enable the ESR at switch On. You just need to link the Red/Yellow wire to the Green of the BAS.

So the Starter, BAS fuse is Not blowing, but somehow upsets power or ground??

Suggest taking good Voltage measurements with the Negative meter clipped onto Battery Negative

Probe.....

-12v on Black wire of the ESR Ignition to On. Voltage should come and Go as you operate the Kill Switch.

- 12v Solid on the Red/White wire of the ESR. This should be there All times Ignition On or Off, source is Main Fuse B 30amp.

- 12v On the Black/White wire of ESR Ignition to On.

Another weak link with the above voltages is the Blue 18P connector, refer your drawing, common problems of high resistance and poor connections  can appear at this connector.

Monitor the voltage at the Clock Fuse probing the tiny fuse test point on top of the fuse. You must see battery voltage here Ignition On and Off. This will confirm Main Fuse A 30amp power is good or bad!

Do the same for the Headlight Fuse F. This will confirm Ignition Switched power is OK or faulty, again you should be measuring battery voltage.

 

[styran]

16 minutes ago, Grum said:

Holy Cow!! You seem to have gone badly backwards from just replacing the Starter Relay plug! Are you confident the wire in the plug ARE going to the correct connections at the Starter Relay?

Assume you're saying it cranks over but doesn't start? Is that correct.

Cranking excessively trying to start it has probably caused flooding.

Might require you to go through the purge process of throttle Fully open while cranking, shuts off injectors purging cylinders.

So if your battery voltage is say 12.5v and you leave your positive meter lead at the battery and you probe any ground point or wire and you're seeing noticeably lower than the 12.5v. This would point to either a bad Negative connection at the Battery or poor main Ground with to frame or engine.

 

Your messing with my head referring to frame ground power! If you have a meter lead on the Battery Neg terminal And you probe any Ground with the other lead AND you measure a voltage, then the Ground is Not properly Grounded.

Any suspicion of the BAS. For test purposes you can easily unplug it and bypass it to enable the ESR at switch On. You just need to link the Red/Yellow wire to the Green of the BAS.

So the Starter, BAS fuse is Not blowing, but somehow upsets power or ground??

Suggest taking good Voltage measurements with the Negative meter clipped onto Battery Negative

Probe.....

-12v on Black wire of the ESR Ignition to On. Voltage should come and Go as you operate the Kill Switch.

- 12v Solid on the Red/White wire of the ESR. This should be there All times Ignition On or Off, source is Main Fuse B 30amp.

- 12v On the Black/White wire of ESR Ignition to On.

Another weak link with the above voltage is the Blue 18P connector, refer your drawing, common problems of high resistance and poor connections  can appear at this connector.

Monitor the voltage at the Clock Fuse probing the tiny fuse test point on top of the fuse. You must see battery voltage here Ignition On and Off. This will confirm Main Fuse A 30amp power is good or bad!

Do the same for the Headlight Fuse F. This will confirm Ignition Switched power is OK or faulty, again you should be measuring battery voltage.

 

We replaced the subharness with an older subharness and still had the issue with positive voltage all over the grounds.

We have not tried cranking yet, if the dash even turns on its super dim. computer is not in because we do not want to fry it.

probing the frame with the conditions i mentioned above will result in positive voltage (4 or 9V instead of ground)

we tested continuity on the ignition switch and it was good.

 

if we turn the KEY to ON/OFF, with the dash unplugged, and the killswitch on STOP, the frame and harness grounds are GOOD.

 

with either the dash plugged in or the killswitch on RUN, all grounds are BAD ONLY with key ON and fuse mentioned in previous reply.

dash unplugged and killswitch RUN with the engine stop relay plugged in will cause it to click but will make all grounds BAD.

without relay, grounds GOOD.

 

we have removed the BAS and just left the connector jumpered (pins 1 and 3 connected). we originally thought it was causing the issue. the bike electronics are stripped down to only the essential components.

when the grounds are bad, they are bad absolutely everywhere except the batter negative and the bolt where the battery negative bolts onto the frame.

even the bolt where the main harness grounds to the frame is also bad with the conditions above.

 

 

 

before it got this bad the dash was lighting up like a christmas tree with erroneous speed readings with the bike stationary

the fuel cut off relay was buzzing continiously as well.

it has gotten so bad that this does not happen anymore and we have the issue mentioned above in the described conditions.

this is a very strange problem and i have never had anything like it before

 

[Grum]

Well, as mentioned above for Ground checking, you Must establish why you have a Ground integrity issue First.....

All grounds must have zero ohms/continuity back to the Battery Negative, and no ground should measure a voltage with respect to Battery Negative, ignition to On and Off.

Check ground bonding starting with the Engine and Main frame Ground. 

I'm assuming battery terminals are clean and tight and you have a charged healthy Battery?

 

 

[styran]

On 3/27/2024 at 1:10 AM, Grum said:

Well, as mentioned above for Ground checking, you Must establish why you have a Ground integrity issue First.....

All grounds must have zero ohms/continuity back to the Battery Negative, and no ground should measure a voltage with respect to Battery Negative, ignition to On and Off.

Check ground bonding starting with the Engine and Main frame Ground. 

I'm assuming battery terminals are clean and tight and you have a charged healthy Battery?

 

 

Battery is healthy. Checked where battery bolts onto frame and that is tight.

Checked where main harness bolts to frame and that is tight too.

with key off, 0V on frame

with key on, killswitch on, 3.3v on frame

something is shorting somewhere.

unplugging the ESR shows 0v on frame.

we then depinned the ESR connector, we removed the black and white wire spade, that did not change anything, still 3v on frame.

We then removed the black wire spade, coming the killswtich on the handlebar. we got the relay to click by jumping the correspoding relay pin with battery postive. 3v on frame.

(this is the same as killswitch on, we are replicating that by jumping to batt positive)

from this we assume that the B/W and B wires are not causing the short.

 

so, when the relay receives 12 V from black wire, that is being grounded to G wire via the bank angle sensor.

 

the bank angle sensor connector is currently being jumped. G wire to R/Y is being jumpered

could that be causing the issue? we have gotten the bike to start before by jumping the bank angle sensor a very long time ago so we dont think this is the problem.

 

another interesting detail is pushing the starter button causes 3v on frame with the ESR in or out.

 

 

[Grum]

- Check the BAS Ground wire for continuity back to Battery Negative. What do you measure?

- Have a close look at where this wire goes through the 18P Blue connector, bad joints and problems have occurred here.

 

For fault finding at this stage keep the BAS bypassed, it stays out of the equation that way. Get the wiring and bike running first Then go back to reconnecting the BAS back to normal.

 

- If there is any suspicion of an issue with the ESR, replace it with the Hi Beam Relay.

 

You can only have a partial short or bad Ground, otherwise you'd be blowing a fuse.

 

So you've confirmed all major grounds including engine ground are clean and good (not just tight) and measure zero ohms back the battery Negative? See attached picture.

 

[Grum]

Wonder if your version VFR has this front harness Ground Block, needs a good inspection if you have.

[styran]

7 hours ago, Grum said:

Wonder if your version VFR has this front harness Ground Block, needs a good inspection if you have.

we inspected that exact yellow ground block in the front subharness in your pictures above.

terminals were silver and in good condition

[styran]

Problem has been found. I have told my buddy several times to both grounds but only checked the main harness ground and never checked the grounding cable that goes from battery negative to the frame under the gas tank hinges. It was quite loose. He has taking his bike for multiple roadtrips and has had no issue since.

 

Thanks for all the help!

[Grum]

Good news thanks for the feedback.

Don't hear of the Frame Grounds going loose like that too often!