Electrical problem, no spark **SOLVED**

[Jobu]

I recently found an intake leak on my bike, so a couple of days ago I fixed that, which required removing the carbs and battery box.  I buttoned everything back up and let the permatex setup.

Went over today to start the bike it just turns over.  My gauge shows no RPM's, which means it is not picking up any induction (usually bounces from zero to about 400).  So, I checked and rechecked my connections becuase I figured I had forget to plug something back-up.  But I found nothing and I am really familiar with the setup of my bike because I have had it apart several times lately, including building a new battery box.

I checked all the connections with a voltmeter for power and everything is getting power and is grounded, including the ignition modules and coils, but they aren't producing any spark?

Any ideas?

[He Man]

Are the plugs good? Have you tried to physically ground the spark plug and look for a spark?

[ducpainter]

...no real ideas...

except I know the modules fire by being grounded....

check the grounds again.

[Jobu]

Are the plugs good? Have you tried to physically ground the spark plug and look for a spark?

The plugs are a perfect brown, first thing I checked.  I have not checked for a visible spark, but I have two different gauges, neither shows any spark.

...no real ideas...

except I know the modules fire by being grounded....

check the grounds again.

I'll definitely check them again.  I was planning on checking one in particular tomorrow.

Do you know off hand how many ground connections there are?  Off the top of my head, I remember four:

1.  The main ground.  This is obviously working because the bike turns over.

2.  The ground from the engine block to the frame.  I took this one off because it never did anything useful.  The bike has ran great without it for over a year now.

3.  A ground at the front of the wiring harness.  I have it grounded where the voltage regulator is mounted.  Have not did anything to it, so it shouldn't be a problem.

4.  The last one that I remember is towards the middle of the harness.  It is grounded (at least on my bike) at the battery box mount.  I removed this one when I removed the battery box, so it could be the culprit (I hope so).  But it did test as being a complete circuit earlier today when I was troubleshooting.

Sorry to be long winded, more trying to help myself remember connections than explain.  Other than these, is it possible that there is a ground some where that I have forgotten.  I looked for one but couldn't find any.

Thanks

[ducpainter]

Put the one from the engine to the frame back.

If you check all the wire sizes you'll notice the one you removed was the largest wire size.

It's crucial to protect the modules. Don't ask me how I know.

Hope you didn't cook them.

The rest of the grounds are all I can remember.

[Jobu]

Put the one from the engine to the frame back.

If you check all the wire sizes you'll notice the one you removed was the largest wire size.

It's crucial to protect the modules. Don't ask me how I know.

Hope you didn't cook them.

The rest of the grounds are all I can remember.

I'll give it a shot.  I had read at some point that the engine to frame ground was only necessary for SS's.

I read it on the internet, so it has to be true.     Thanks for the advice, I'll give it a shot.

Is there anyway to test them to make sure they aren't fried?

[Howie]

I'll give it a shot.  I had read at some point that the engine to frame ground was only necessary for SS's.

I read it on the internet, so it has to be true.     Thanks for the advice, I'll give it a shot.

Is there anyway to test them to make sure they aren't fried?

That ground is important.  Without it you are depending on greased engine mount bolts, and even worse, throttle and choke cable for a good ground.  If the bike still doesn't make spark I will send you a test sequence.

[Jobu]

That ground is important.  Without it you are depending on greased engine mount bolts, and even worse, throttle and choke cable for a good ground.  If the bike still doesn't make spark I will send you a test sequence.

Howie, it still won't fire. What is the testing procedure? Thanks.

Actually, I just found this from TOB.  I'm pretty sure it was you who posted it:

The following is a test sequence from the shop manual. The last person I gave it to got opposite results, but it turned out the modules were good

VB 1G 1 G P+ P- positive lead

negative lead VB O O O O

negative lead 1G 1 X X X X

negative lead G X O O O

negative lead P+ X O O O

negative lead P- X O O O


Where there is an O the meter oscillates
Where there is an X it does not.

So, now all I need is for this to be in English.  I understand you are referring to the five leads coming out of the ignition module, but how exactly is the test performed? 

[Howie]

Yes, I posted it.  It is retyped from my shop manual.  I never used it myself, but one person on TOB did with mixed results, I think on his bike it worked opposite.  Anyway, a foolproof alternative would be to try your modules on a known running bike.

[Jobu]

I've been out of town for a while, but finally got a chance to troubleshoot more today.

So:

1.  I was able to test the ignition modules on a running carbed bike and it fired right up with my modules plugged in.  So that isn't the problem.
2.  All grounds are good, everything is getting power.
3.  I checked my Dyna coils with the resistence check and they are  .
4.  Also checked the resistence of the pick up coils and they are within spec (~100 Ohms).  Obviously couldn't check the air gap without pulling side cover which I DON'T want to do.

So now I'm at a loss again and this is make the beast with two backsing getting old fast. 

The ignition relay seems fine, but is that a possiblity for a problem?  I don't have a Haynes manual right now but should soon.  Someone has Rameses's book which is the one that I use.

Also, what about a side stand problem?  Did a 1997 M750 have a side stand shut off switch?  'Cause this one didn't when I got it.

Any more ideas form anyone?  Thanks.

[Howie]

If your headlight, signals, brake light and horn work it is not the relay.  No safety (sidestand) relay or switch on a '97.  Only two things I can think of off hand.  Make sure the black wires from the modules are grounded and the red wire to the modules has battery voltage.  No voltage?  Start back tracking.  Oh, a third thing.  If your voltmeter has an AC setting, the connector at the ignition modules that have two wires are from the ignition modules.  You should pick up an AC voltage reading there.  I have no idea of the voltage value, but it will probably be low.  Disconnect the modules to do these tests to avoid hurting the espen$ive modules.

Oh, I missed the part in your post where you asked the test sequence to be turned into English, but what you did is more positive anyway.  Sorry.

[SP3]

Howie, it still won't fire. What is the testing procedure? Thanks.

Actually, I just found this from TOB.  I'm pretty sure it was you who posted it:

The following is a test sequence from the shop manual. The last person I gave it to got opposite results, but it turned out the modules were good

VB 1G 1 G P+ P- positive lead

negative lead VB O O O O

negative lead 1G 1 X X X X

negative lead G X O O O

negative lead P+ X O O O

negative lead P- X O O O


Where there is an O the meter oscillates
Where there is an X it does not.

So, now all I need is for this to be in English.  I understand you are referring to the five leads coming out of the ignition module, but how exactly is the test performed? 

They use the word "oscillate" where you should get a steady reading i.e., P- to P+ = about 2k ohms. X means open circuit (overload/infinite impedence). Later today (hopefully) I will post my results from two sets of working modules.

[SP3]

Alright, here is one of my original modules. I scanned the factory manual page and used MS Paint to insert my readings.





This one is from the vertical cylinder. I will try and post the horizontal one later but the readings are essentially identical.


Since the image here is sort of IZ_, here is the link to the page for the full size:

http://s100.photobucket.com/albums/m32/SP3-322/?action=view&current=IMG_0008a.jpg

[Rameses]

The modules have already been ruled out as the problem though.

When they were put in a different bike it functioned perfectly.

[SP3]

My post was more of an FYI than anything else since the modules are a mystery to many.