My 930 won't start after sitting for a couple of hours unless I pull a spark plug wire. I pull a wire, it starts. I turn 'er off put the wire back on and she starts up. Let 'er sit for a while and she won't cooperate again. Why would pulling a wire allow it to start up?

Anybody ever heard of such a thing...? TIA for help solving this nagging oddity.
Cheers, PDQ

 

Have you checked your ignition timing?

 

Yeppers. Not the issue.

 

So when it does start, you have it running on only 5 plugs (one wire removed). Shut her down, plug the wire back in, and she starts right up on all 6. Shut her down for 2 hours, then nothing again until you repeat the magical sequence.

This symptom doesn't make any sense. Got power to the coil at all times? And is your coil wire clean and in good shape? I would say check your coil resistance as well (for whatever the spec is). I'm thinking the coil is going south on you (or your CDI or MSD or whatever ignition system you have), creating insufficient spark to get all 6 plugs sparking enough to start the cold engine. Pull one wire, and the other 5 plugs now spark just enough to fire the beast up. Then, once warm running on 5 plugs and connecting the 6th back up would probably still start even though t he coil output is weak.

Oh, and don't forget to have good grouding on all components.

All just a big guessing game, by my 2 cents for what it's worth.

 

Hope these resistance readings may help...



OK, here are the resistances

At the CDI connector with it unplugged

Coax to dizzy (green cable) is 570 inner to outer wire.
Brown to White (coil primary) is .7

Coil secondary (coil HT to either + or -) is 649

At the CDI box

31/1 to 31d is 0 (closed circuit)
31d to 15 is 672
31d to TD will charge briefly and then go to infinity (open circuit)
31/1 to TD also charges briefly and then goes to infinity (open circuit)

My CDI is a 930.602.702.00
Bosch number 0 227 300 004

 

Try a new/different rotor - cheap and fast experiment.

 

Floating ground??? Check all ground leads around the engine area to chassis. Also check the over-boost switch leads/switch around the IC area.

 

Thanks guys, checking things as recommended and will let you know the outcome.
CHEERS!

 

did you find the problem yet????

 

It would seem the coil or CDI is bad to me. The coil is cheap to replace compared to the CDI although it is much more likely to be the CDI...