Engine stops when gear engaged.


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OldBill388
Posts: 11
Joined: Fri May 06, 2016 1:42 pm
Location: Cambridge, England
Motorcycle: 1994 GL 1500 SE R
2016 Triumph Tiger 800 XCa

Engine stops when gear engaged.

Post by OldBill388 »



Hi everyone.
I have a 1994 GL1500SE with 120k miles on it.
It runs very well since I put new plugs and filters in and cleaned the carbs.
Since doing that last week I've been for a couple of runs and it's the best it's ever been.
It had a new alternator recently and a new battery so they helped I've no doubt.
My problem is that I started it as normal this morning on choke and after a couple of mins it settled down to run without (ambient temp is about 7°C here in the morning)
Engaged first gear as I needed to do a bit of back and forth to get out the gate down the small slope to the road (reverse not used) Parked up at the side of the road and put it in neutral. I put it in gear to move off which is when the ignition cut out. It stopped like I'd used the kill switch. Back to neutral and restart but with the same result.
Bike pushed back through gate and investigation begun.
The side stand switch was cleaned and tested with a meter. It works correctly. Also checked on the bike and with a powered circuit tester.
The clutch switch is also working correctly.
The reverse switch checks out ok too.
I checked the bank angle sensor as far as it can be. I shook it and can hear something moving inside. I cant see a leak of any kind. The bike wouldn't run if the BAS was faulty I guess.
I checked all the fuses in the fuse box and a couple of relays that seemed relevant.
The only other thing I can think of to check is the gear position switch but the connector is not where the Haynes manual says it should be.
The neutral light goes out when I engage gear and the starter won't operate until the clutch lever is pulled as if the kill switch is in the off position.
Does anyone have a viable theory as to what the issue might be please?
It's never done this before.

Your help is greatly appreciated.


User avatar
DenverWinger
Posts: 2011
Joined: Thu Jun 23, 2011 2:20 pm
Location: Denver, CO
Motorcycle: (s)
1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Engine stops when gear engaged.

Post by DenverWinger »

I doubt it is the gear position switch, disconnecting that switch would have the same effect as shifting to 1st gear.

There's two circuits and a common ground going to the switch. The switch provides ground to the bulb circuit when down, then provides ground to the ignition system and thru the clutch switch to the starter circuits when sidestand is up. Since you can operate the starter in gear by pulling the clutch that tells me the sidestand "Up" circuit is working.

Looks like Right side plastic will have to come off to access the ECU.

The ECU depends on having a ground on the LT-GRN/RED wire (pin 11) from the gear position switch's neutral line OR a ground on the GRN/WHT wire (pin 6) from the sidestand switch to make sparks for the plugs, if BOTH grounds are missing the sparks stop. Since it runs in neutral, but not in gear with sidestand up this suggests a fault in the side stand circuit.

Use a test light to confirm ground on the GRN/WHT wire at the ECU when the sidestand is up. Possible this GRN/WHT wire has a bad connection in the ECU plug. Or the fault may be INSIDE the ECU.

The ECU is somewhat serviceable if you open it up. People have replaced blown fuel pump drive transistors.

I'd bet inside the ECU that the ground from the Neutral switch and the ground from the sidestand each pass thru a Diode to a common point in the ignition circuit. If you've confirmed good ground on GRN/WHT wire from sidestand, I'd suspect a bad Diode INSIDE the ECU.

(Wish I had a good schematic of the inside of the ECU)
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark
User avatar
OldBill388
Posts: 11
Joined: Fri May 06, 2016 1:42 pm
Location: Cambridge, England
Motorcycle: 1994 GL 1500 SE R
2016 Triumph Tiger 800 XCa

Re: Engine stops when gear engaged.

Post by OldBill388 »

Hi Denver Winger.
Thanks for your info. It may well solve the problem.
I found the gear change sensor connection and disconnected it. There's nothing from the switch side as I guess there's no power other than that from the ECU.
I used a test light using it to earth the circuit on the ECU side of the harness.
When in neutral I got power from the neutral wire and a lower current from the overdrive circuit.
It did the same test for 2nd and 3rd and got the same result. IE live from neutral and OD.
User avatar
DenverWinger
Posts: 2011
Joined: Thu Jun 23, 2011 2:20 pm
Location: Denver, CO
Motorcycle: (s)
1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Engine stops when gear engaged.

Post by DenverWinger »

Sounds like everything related to gear position switch is good, as I expected.

Problem seems to be the ECM thinks the sidestand is down, even when it isn't.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark
User avatar
OldBill388
Posts: 11
Joined: Fri May 06, 2016 1:42 pm
Location: Cambridge, England
Motorcycle: 1994 GL 1500 SE R
2016 Triumph Tiger 800 XCa

Re: Engine stops when gear engaged.

Post by OldBill388 »

Tomorrow I'll do the tests you suggest but I think it may be to just confirm your opinion.
I'll let you know the results.
Thanks for your help.
User avatar
OldBill388
Posts: 11
Joined: Fri May 06, 2016 1:42 pm
Location: Cambridge, England
Motorcycle: 1994 GL 1500 SE R
2016 Triumph Tiger 800 XCa

Re: Engine stops when gear engaged.

Post by OldBill388 »

Today I carried out a check of the gear position sensor. I connected a live probe to each terminal in turn changing gear for each one.
As DenverWinger predicted all worked correctly.
I then tested the earth wires as suggested and found them to be in order too.
However when I took the ECU multipin plug cover off the plug fell out!
Having pushed it in I realised the catch that should hold the plug in was broken off.
The bike works properly again now though.
Without DenverWingers advice I wouldn't have found the fault for some time so thanks for the advice.
I'm probably going to fit a screw through the cover to hold the plug in place.
On the plus side all my electrical connections are very clean!
GoldwingDocs wins again!
User avatar
DenverWinger
Posts: 2011
Joined: Thu Jun 23, 2011 2:20 pm
Location: Denver, CO
Motorcycle: (s)
1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Engine stops when gear engaged.

Post by DenverWinger »

Glad it turned out to be something that simple. :D (well, not entirely simple, you had to remove a bunch of plastic to find it). :lol:


♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark
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