Intermittent (& Maddening) Engine Cutting Out...

[Gerry_L]

Cap in hand and begging for help here. I've been trying to sort my 2002 V11 Sport for way too long and I'm at the end of my tether.

I'm desparately looking for suggestions that I haven't thought of.

It cuts out suddenlt without warning - complete and instant - but kicks back in immediately I feather the clutch. Sometimes it'll backfire if I stuff up the clutch work but has never stranded me. Some days it will limp home cutting out very few kms, some days it can run perfectly all the way home. (I only take it out when I'm testing a new fix).

It can run perfectly for 2-300 kms or it can do it 2 kms from home. Hot weather/cold weather.

To date I've tried:

 - Clutch & sidestand switches

 - All new 20A Omron relays (and re-tightened the spade connectors in the relay blocks)

 - New ignition sensor (wiring had gone hard and brittle)

 - New filter & fuel hoses (with heat insulator over the tank line)

 - Checked, cleaned and tightened all earths.

 - Brand new battery (charging at > 13.5V)

 - Swapped ECUs (it runs a Jefferies myECU unit but I have the same one on my Cali - I can swap them easily then just load the appropriate map. Cliff checked and re-flashed one of them for me when I was fiddling with the relays and caused some mischief).

 

Still to come:

- new fuel pump on its' way (not convinced this is the problem but I'm grasping at straws here).

- Dismantle main switch and check contactors and soldering.

- new fuel tap

 

Please feel free to add to this list - the answer will be there somewhere I'm sure.

Thanks in advance

 

 

[docc]

" - Dismantle main switch and check contactors and soldering."

@Gerry_L , if this means the key-activated "Ignition Switch", by all means: yes!

20A OMRON (G8HN ?) are not full-on High Current OMRON (G8HE) . . .  vital for Position#5 (Fuel/Ignition)! And Position #1 on an early Sport! > High Current < relay positions!

There are also the weak, hidden spade connectors under the fuse block to fuses #1/#2 (Fuel/Ignition and ECU):

Otherwise, it's Tank Off Maintenance Checklist and another Decent Tune-up to catch up all the stray issues . . .

 

[knumbnutz]

I've got sort of the same thing, but it cuts out for 1/2 sec.

But... I had a TRX and it had was getting harder and harder to start. Every time I thought I found a reason it proved not to be it.
Eventually it was a fracture on the pcb of the ecu and once I was able to get another ecu it suddenly became an easy fix.

From that experience I would say you are doing all right things.

Sent from my ELE-L29 using Tapatalk

[Gerry_L]

@docc thanks for the excellent feedback! 

I do have the G8HE's - I got the reference from this forum and had to buy them from the US. Couldn't find them in Australia.

The fuse block is a good lead - will head out to the garage and hit that one now. May as well do the ignition switch while I'm there.

I've done most of the things in the tank-off list and it's tuned to within an inch of its' life. When it isn't playing up it runs so sweet it would make a grown man weep tears of joy.

When I finally get to the bottom of this I'm gonna ride the wheels off it!

Thanks again.

[Chuck]

My first thought was ignition switch, but when feathering the clutch brings it back to life? Hmmm.

[Gerry_L]

@Chuck I do agree with your logic, but as per my comment on the fuel pump, I'm down to clutching at straws here.  

Like everything else I've tried so far, even if it doesn't fix the problem it all adds to a better runninng bike (eventually)...

[Lucky Phil]

11 hours ago, Chuck said:

My first thought was ignition switch, but when feathering the clutch brings it back to life? Hmmm.

Maybe this is a red herring Chuck. I looked at the wiring diagram as well and couldn't come up with an answer on that with regards to the clutch switch and a running engine but here's a thought. When it dies ( and the OP hasnt mentioned if this means just the engine or complete electrical power) I will assume engine only, the natural instinct is to whip the clutch in and start modulating the throttle to keep it running. Maybe it's worth thinking more about what's happening with the throttle and the TPS as a possible issue.

Ciao 

[docc]

43 minutes ago, Gerry_L said:

@Chuck I do agree with your logic, but as per my comment on the fuel pump, I'm down to clutching at straws here.  

Like everything else I've tried so far, even if it doesn't fix the problem it all adds to a better runninng bike (eventually)...

This outlook reminds me of chasing MySport's "Nasty Hiccup" for over ten years. I learned a lot, addressed many issues, and even found a few contributors.

Two that come to mind, without reviewing that entire thread, were a mildly faulty TPS and a badly corroded/broken contact inside one of the coil boots (both easy to check).

I have never been able to detect a glitch in the TPS output watching changes in mV, but instead set to a sensitive resistance setting (Ω) and very slowly open and close the throttle plate watching for jumps and opens.

The coil wire fault was a very satisfying find!

[Lucky Phil]

Yes docc and here's what the inside of an earlier TPS looks like after a while. Note the crud and debris on the wiper and track.

 

Ciao

[gstallons]

The foil is GONE .

[Lucky Phil]

9 minutes ago, gstallons said:

The foil is GONE .

There is no foil on the tracks.

Ciao

[Chuck]

1 hour ago, Lucky Phil said:

Maybe this is a red herring Chuck. I looked at the wiring diagram as well and couldn't come up with an answer on that with regards to the clutch switch and a running engine but here's a thought. When it dies ( and the OP hasnt mentioned if this means just the engine or complete electrical power) I will assume engine only, the natural instinct is to whip the clutch in and start modulating the throttle to keep it running. Maybe it's worth thinking more about what's happening with the throttle and the TPS as a possible issue.

Ciao 

I agree.. looked at the schematic and it looks to me that it is only involved in starting. It just seems strange that it always works.

Quote

Sometimes it'll backfire if I stuff up the clutch work but has never stranded me.

That sounds like ignition has been lost then returns after a few revolutions. I'm sure it is frustrating, but think of the pleasure you will get from solving it.

[knumbnutz]

My first thought was ignition switch, but when feathering the clutch brings it back to life? Hmmm.

Could it be the side stand is not resting hard against the switch?

Sent from my ELE-L29 using Tapatalk

[docc]

57 minutes ago, Lucky Phil said:

Yes docc and here's what the inside of an earlier TPS looks like after a while. Note the crud and debris on the wiper and track.

 

Ciao

And there is no way to clean or maintain them?

[LowRyter]

On 4/25/2021 at 8:23 PM, Gerry_L said:

Cap in hand and begging for help here. I've been trying to sort my 2002 V11 Sport for way too long and I'm at the end of my tether.

I'm desparately looking for suggestions that I haven't thought of.

It cuts out suddenlt without warning - complete and instant - but kicks back in immediately I feather the clutch. Sometimes it'll backfire if I stuff up the clutch work but has never stranded me. Some days it will limp home cutting out very few kms, some days it can run perfectly all the way home. (I only take it out when I'm testing a new fix).

It can run perfectly for 2-300 kms or it can do it 2 kms from home. Hot weather/cold weather.

To date I've tried:

 - Clutch & sidestand switches

 - All new 20A Omron relays (and re-tightened the spade connectors in the relay blocks)

 - New ignition sensor (wiring had gone hard and brittle)

 - New filter & fuel hoses (with heat insulator over the tank line)

 - Checked, cleaned and tightened all earths.

 - Brand new battery (charging at > 13.5V)

 - Swapped ECUs (it runs a Jefferies myECU unit but I have the same one on my Cali - I can swap them easily then just load the appropriate map. Cliff checked and re-flashed one of them for me when I was fiddling with the relays and caused some mischief).

 

Still to come:

- new fuel pump on its' way (not convinced this is the problem but I'm grasping at straws here).

- Dismantle main switch and check contactors and soldering.

- new fuel tap

 

Please feel free to add to this list - the answer will be there somewhere I'm sure.

Thanks in advance

 

 

Mine does that when low on fuel.  Really.