NO SPARK AT LH PLUG

[Guzzi_Don]

 I have a T4 850. The bike has a Dyna III electronic ignition fitted. There is no spark at the LH spark plug. There is spark on the RH plug when ign is turned on and off. I have removed the coils and transposed the wiring between the coils to test. Both of the HT leads seem ok as do the coils themselves. When the RED wire from the loom is attached to each coil in turn then the respective plugs spark (LH and RH). When the GREEN wire is attached to each coil in turn there is no spark from either spark plug when ign it turned on and then off.

Any ideas? Does it mean the Dyna III unit has had it or am I looking for an O/C in the GREEN wire between the LH coil and the Dyna III unit mounted on the top frame tube. I have not removed the petrol tank yet to check anything under there.

Thanks

[Kiwi_Roy]

The Dyna module outputs are Red and Green as you described so the red one is working, green one not but it could also be the input to the Dyna module from the sensor in the cam area, white and Black I think, try swapping those over to see if it makes the green output work.

Is this a system you are trying to commission or one that suddenly quit?

[Guzzi_Don]

Hi again Roy,

It is one that just quit. It had been running fine for about 10,000km. It was running fine when I last rode it about 3 weeks ago. I started it up and it was only running on one cylinder. Hence the description that I have given. Good suggestion though, I had not thought of that.

Thanks

BTW the relay suggestions that you gave me are all working fine.

[Tom]

 

[guzzisteve]

Use a known working spark plug also.

[charlie b]

So, does the bike run on one cylinder or does it not run at all?  IIRC, not sure if the dyna will 'fire' both plugs with just an on off of the ign switch.

FWIW, I'd check for operation by removing both plugs and resting them on the cyl heads (to get a ground) and then turn over the bike with the starter.  See if both plugs spark.  (this is what Dyna calls for in their troubleshooting guide that you can find on their web site).

[Guzzi_Don]

I have had both plugs grounded when tuning the ign switch on and off and under normal conditions both plugs do spark as the key is turned to the off position.

And all the plugs I have been using have been swapped from side to side so they spark on one HT lead but not on the other.

Thanks for the suggestions. I will look up the Dyna trouble shooting info on there site for the III model.

[pete mcgee]

http://www.airheads.org/sjm-test-menu/88-tt-12-engine-electrical-system/250-dyna-iii-electronic-ignition-troubleshooting-guide

This may help.
Read it all then go fiddle with wires.

[Guzzi_Don]

Thanks Pete

[Aaron D.]

My experience is that this type of failure in a Dyna is a broken solder connection. See if reattaching the green wire will help.

[Kiwi_Roy]

http://www.airheads.org/sjm-test-menu/88-tt-12-engine-electrical-system/250-dyna-iii-electronic-ignition-troubleshooting-guide

This may help.
Read it all then go fiddle with wires.

WTF, you have to join the airhead beamer club to read the rest, how retarded is that?

[charlie b]

http://www.dynaonline.com/support/downloads.aspx?p_v=DYNA%20III

When I had a coil go bad it took out the Dyna III module on that side.

[Tom]

There was a time that Dyna had some quality control problems with their black boxes.  Hopefully it's not from that batch.  Curtis persuaded me not to buy one to put in my Cali III.  I did go back to points/condensors.  Dick Gutherie, the WA State MGNOC rep.  said he went through 3 boxes on his Cali III.  This was a number of years ago.