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Ignition problems

Posted: Mon Sep 02, 2019 4:27 am
by Per-Erik
First of all thank You for a very good forum and letting me in.
My name is Eric and I live in Finland. I have been riding bikes since I was 16.
Everything from Ducati, Royal Enfield etc etc... I am not a mecanic or electrician but
I am a private pilot and like to solve problems in a systematic way.

So now to my problem were I really need You help.
I bought my GL1500 last year so running my second season now with 165.000 km on the tacho.
It sits in my garage all the time.

The Story......
I come home one sunny day parked it in front of my house, 2h later started it in drove it in my garage.
Went to bed. Next day did not start, cranked but no spark..
I NEVER had ANY issues with my bike.
- I have a brand new fully charged battery.
- Changed all spark plugs this year.
- I disconnected the Bank Angle sensor ( After that You can not crank at all )
- Took the seat away checked relays... I heard them click
- Checked the kill switch for power and Yes the former owner has overide it so the killswich is always on.
- Check the cruise control indicator
- Side stand swich ok
- Clutch handle with the switch checked.
- I took out a spark plug.. no spark. Finally later I did NOT take out the plug just the hat and put another spark plug in...
- Tried to see any loose connections on the (ECM) I think You call the black box on the right side at about knee hight.
- New fresh petrol
- While cranking, no spark it got to much fuel I suppose because it started to "coff and bang" sound from the front part of the engine
THEN AFTER DOING NOTHING SUDDENLY IT STARTED with one spark plug cable disconnected.
Run perfect. I killed it and put the cable back to the spark plug...
Perfect smooth run...
Now I was getting worried because I did not find the problem.
I decided to once again charge the battery over night to be 100% shure. While cranking it meashure voltage direct over battery. ok
So Next day... started like a baby smooth no issues..
I went driving in the sunshine with some good old rockn'roll music... 1km 2km 3km Hell Yes problem gone.... :D
Suddenly :oops: :oops: BANG PANG ... **** Ignition cut out 1 sec and then back on for about 20 times scaring the **** out of me....
I was driving with cruise control at about 80 km/h.
Finally it died all light working stereo to...
I switched all light off, cruise off, stereo off, while still rolling at 80 kmg tried to restart it with the start switch...
Starter worked when I pressed the cluch switch but no start (probably no spark) so rpm meter did not rise so it was cranking.
Then I thought why not try to start it while rolling with 5:th gear "old school" because I still had 70 km/h let the momentum work.
Funny enough it started but as soon as Rpm was lower it died..
Tried this many times starter worked it cranked but no spark not starting with the "run" starter swich
BUT with the momentum and realeasing the cluch it started...
Finally after some **** in my pants it started to work like a smooth clock again...
I was able to drive it home in the garage.... I started it for several times and days... works like a charm...
How the f.. shall I find this problem.......

I would be VERY VERY VERY Happy for someone to help me in a systematic checklist way so I can drive again. We still have 4 weeks of good weather here so I cound every day.....

Very best regards from a sad bike rider.....


Re: Ignition problems

Posted: Mon Sep 02, 2019 8:05 am
by Erdeniz Umman
It seems like there is a broken wire, loose or bad connection on the ignition circuit.
It is hard to troubleshoot intermittent problems.
What is the brand and the type of the spark plugs you have installed?
Here are the diagrams for the 88 European models.

Re: Ignition problems

Posted: Mon Sep 02, 2019 8:30 am
by Per-Erik
Thank You very much for Your help so far...
Answer: I use NGK DPR7EA9

Add to my old text.
Bike was not washed or in rain...
Reverse handle and circuit checked and woking.

I would like also to know this to help me on my journey :)
What can cause this and also what NOT..
I mean by using that method I can at least forget xxx possabilities.

What can CUT OUT ALL IGNITION when driving and what can not.

Once again I am very greatful thank You.

Re: Ignition problems

Posted: Mon Sep 02, 2019 8:49 am
by bellboy40
As Erdeniz said, it is difficult to troubleshoot an intermittent problem. It seems you are losing power to the ignition circuit. Does the "cruise on" light stay on steady when you are having this trouble? I would check where the previous owner messed with the wiring on that stop/run switch. Could be a bad connection there. The power for the ignition goes through relay 8 then to that switch and then to the coils. I would be checking out that circuit.

Re: Ignition problems

Posted: Mon Sep 02, 2019 8:57 am
by Erdeniz Umman
There maybe a lot of reasons.
Most common problem is the kill switch itself. Although you mentioned it is shorted, check it again.
Bad bank angle sensor can be the culprit, especially after passing over a bump.
Bad side stand switch can kill the engine when in gear.
Pulse generator wires could be broken somewhere, etc, etc.

It would be better to perform Ignition Control Unit test given below when you have the problem again, and then continue troubleshooting accordingly.

Re: Ignition problems

Posted: Wed Sep 04, 2019 4:03 pm
by ct1500
Per-Erik wrote:
Mon Sep 02, 2019 4:27 am
First of all thank You for a very good forum and letting me in.
My name is Eric and I live in Finland. I have been riding bikes since I was 16.
Everything from Ducati, Royal Enfield etc etc... I am not a mechanic or electrician but
I am a private pilot and like to solve problems in a systematic way.
When diagnosing a troublesome 1500 first do a pre-flight check of major systems. Charging voltage, battery load test, fuel pump pressure (1.5psi) and petcock check. Petcock needs to have vacuum available at hose when running, once that is verified attach external vacuum pump to valve and verify it can hold a vacuum. Remove outlet hose (to carbs) at valve and inlet hose at pump cover. Pull a vacuum again at valve and blow through the hose from pump to verify flow, remove vacuum and verify no flow. Some of your symptoms could possibly be fuel related and a machine this age should have these checks done anyways. Fix it right the first time or put zippers on the panels for speedier future removal. :D

You will never diagnose an intermittent running problem until plastic such as top shelter and inner fairing panels are removed and if that means panels stay removed while riding for problem to appear, so be it.

You are grounding the shell of spark plug when checking for this no spark condition, right? The last cylinders on the engine 5&6 are the ones to check ignition spark on a no-start as they are easy to get to with a spare plug. With plastic removed and engine running you do a wiggle test of harness wiring and connectors most notable from ECM, wires going to coils and pulse generator connector above right fan and all other wiring accessible. The white 4 wire connector to the right of carbs outside of frame is a good test point for checking voltage on the blk/wht wire during a no-start or stall which feeds ECM and coils.

Re: Ignition problems

Posted: Thu Sep 05, 2019 1:29 am
by Per-Erik
Hi !
It makes sence..
So I have my incoming weekend saved :)

I will report back.

Thanks all of You....

Re: Ignition problems

Posted: Thu Sep 05, 2019 2:08 am
by terryt
Also check to see if the alternator is charging. and the fuel pump do a fuel flow test.