No spark on '85 GL1200 LTD


Information and questions on GL1200 Goldwings (1984-1987)
  • Sponsored Links
Big-Bob
Posts: 30
Joined: Wed Aug 03, 2011 10:54 am
Location: Phoenix, AZ
Motorcycle: 1985 GL1200 LTD
2001 XT225
2002 Vulcan 750
2009 Ninja 500

No spark on '85 GL1200 LTD

Postby Big-Bob » Tue Dec 11, 2012 2:42 pm



My LTD has been running fine for the past year or so. I originally bought it as a project, and had to do a lot of work on it to get it running and roadworthy. But I have not done anything to it since, other than ride it. It sat for about a week, and when I tried to start it (with a fully charged battery, I keep a battery tender on it) it wouldn't even fire. I checked the spark at one cylinder and got nothing. So I checked for a spark at the other cylinders and got nothing. There are no trouble codes on the ECU. I've already checked the basics, I have 12V to the coils and to the spark units. I have a ground to the spark units, The injectors click when the throttle is turned. The fuel pump comes on and then shuts off like it is supposed to. So do all the LEDs on the ECU. I disconnected the TPS and intake air temp sensor (one at a time) and got the appropriate trouble codes. One thing that puzzles me is that back when I was still working on it I had a no start condition, which turned out to be a bad condition at the resistor mounted on the rear fender. I got 2 trouble codes, one showing that the injectors had failed, the other showing the ignition had failed. I located and fixed the problem, and it started right up, and the trouble codes went away. This time I tried disconnecting that resistor, and get no trouble codes at all. I have tried it 3-4 times, and get nothing. So something has changed. It should show the same code it did the first time the resistor was disconnected shouldn't it? I would appreciate any and all suggestions. I have been working on it for almost a week, and have checked and rechecked everything I know about. I have checked pretty much every connection on the bike. It cranks just fine, just no spark. Thanks, Bob.



User avatar
virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: No spark on '85 GL1200 LTD

Postby virgilmobile » Tue Dec 11, 2012 4:50 pm

I'll look into the schematic,but I suspect there is no pulses being received by the ECU from the pulse coils,or the engine speed sensor(coil).
There is a electrical test manual you can download under the Manuals section.
I'd recommend starting at the plug up front and inspecting for corrosion and then measure continuity of the pulse coils.The same resistance should show up at the plug on the ECU.b

Big-Bob
Posts: 30
Joined: Wed Aug 03, 2011 10:54 am
Location: Phoenix, AZ
Motorcycle: 1985 GL1200 LTD
2001 XT225
2002 Vulcan 750
2009 Ninja 500

Re: No spark on '85 GL1200 LTD

Postby Big-Bob » Tue Dec 11, 2012 6:07 pm

Thanks. I'll check that. That is something I have not checked before. Bob.

Big-Bob
Posts: 30
Joined: Wed Aug 03, 2011 10:54 am
Location: Phoenix, AZ
Motorcycle: 1985 GL1200 LTD
2001 XT225
2002 Vulcan 750
2009 Ninja 500

Re: No spark on '85 GL1200 LTD

Postby Big-Bob » Tue Dec 11, 2012 8:39 pm

Still unable to find anything wrong. According to the manual, the ECU should show a trouble code if either of those things are wrong. The ECU does have power, all the LEDs light up momentarily when the ignition switch is turned on. I have disconnected a couple of sensors to see what would happen, and the ECU showed the proper code. Otherwise I get no code. I also don't get a code when that resistor with 2 white wires and one black wire is disconnected, and I should. I have basically checked everything in the book, and not found anything wrong. Everything else works fine, just no spark at all 4 cylinders.

User avatar
virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: No spark on '85 GL1200 LTD

Postby virgilmobile » Tue Dec 11, 2012 8:51 pm

OK,I guess the next thing is to find that resistor your talking about and see how it can affect the ignition.
I'll double read about the trouble codes too,I don't remember any mention about a code light for a open circuit on the front pulse coil.
Did you happen to check the resistance of it?
I think it's somewhere around 4-5 hundred ohms.not sure.

Big-Bob
Posts: 30
Joined: Wed Aug 03, 2011 10:54 am
Location: Phoenix, AZ
Motorcycle: 1985 GL1200 LTD
2001 XT225
2002 Vulcan 750
2009 Ninja 500

Re: No spark on '85 GL1200 LTD

Postby Big-Bob » Tue Dec 11, 2012 10:08 pm

Not sure what the resistor actually does, but it is connected to all 4 injectors, and when it is disconnected, both fuel injection and ignition are shut down, and it is supposed to show 2 separate codes. If by "pulse coil" you mean the Ns sensor (crankshaft angle sensor) yes there is a code for that. But I will check it again tomorrow.

User avatar
virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: No spark on '85 GL1200 LTD

Postby virgilmobile » Wed Dec 12, 2012 9:07 am

Correct you are......
Because you can hear the injectors click and you have 12 volts on the coils,I see only a few other things.
First,the ECU is not like a new car computer.It can detect only a complete failure of a system.
A part can be out of specs and the ECU still "thinks" it's there and working.
Also,the sensors.....pulse coils,crank angle sensor,throttle position sensor all are provided 5 volts from the ECM as a reference voltage.
I did see one in Canada where the 5 volts measured just under 3.8 volts.The bike just barely would run.
I believe corrosion got into the ECU plug as he unplugged it and plugged it back in several times and magically it started working.The 5 volts came back.
I think it's easiest to measure at the TPS plug.
The other is to measure the pulse coils (Gr/Gl,Ns) resistance....

Big-Bob
Posts: 30
Joined: Wed Aug 03, 2011 10:54 am
Location: Phoenix, AZ
Motorcycle: 1985 GL1200 LTD
2001 XT225
2002 Vulcan 750
2009 Ninja 500

Re: No spark on '85 GL1200 LTD

Postby Big-Bob » Fri Dec 28, 2012 10:02 pm

I finally found it. It was an open circuit in the yellow/red wire that goes from the starter switch to the starter relay, and then to the ECU. The first time I checked it it showed OK. I checked it again and got no continuity between the starter relay and the ECU. I hooked up a jumper wire, and it started right up. Apparently input from this wire controls the ignition and ignition timing on startup. I looked a little further, and unwrapped part of the wiring harness under the seat, and found the source of the problem. There are THREE yellow wires connected together inside the harness. One goes to the starter relay, one goes to the ECU, and I have no idea where the other one goes. One of them was broke, the one between the ECU and starter relay. The schematic does NOT show that connection, or the extra yellow/red wire. It shows the yellow/red wire coming from the starter button, going to the starter relay, and then to the ECU. Someone suggested the other wire might go to the RADIO?? Anyway, an open circuit in this wire kills everything, and will not show a code on the ECU,

I appreciate all the help from everyone. I have a lot of work and money invested in this bike, but I no longer trust the fuel injection or the electronics. I plan to get a carbed 1200, and I can use most of the new parts I put on this one on it. With old bikes, I need something I know how to work on.




Return to “GL1200 Information & Questions”




Who is online

Users browsing this forum: No registered users and 3 guests