JD 322 ignition module testing

[angelugs]

I have a JD 322 that is only running on 2 cylinders. I have a technical manual and have been trying to run down the problem. Basically I've been checking for continuity on the parts in the ignition system. Everything seems to be okay till I get to the ignition module. When I test the contacts one way I have continuity everywhere I'm supposed to. But when I switch the leads from my meter I have no continuity on the same contacts I just previously checked. The chart says I should have continuity on certain contacts regardless which way the meter leads are connected. It looks to me like I have a bad ignition module but at over $300.00 to replace it I don't want to THINK that's the problem. Has anyone else ever checked continuity on the ignition module's contacts and can verify they had flow no matter which meter lead was on the contacts?

Thanks in advance for your response.

 

[Amvcane]

If you know which cylinder is not firing could you just switch that cylinders coil pack with a working cylinder and see if your problem moves?

 

[angelugs]

Thanks for your input. I've tried switching spark plugs AND the coil leads on the cylinder that's not firing. The cylinder still didn't fire with a plug that was firing on another cylinder. Switching the leads with a coil that was firing on a good cylinder still didn't cause the bad cylinder to fire.

 

[radios1]

I think you probably don't have sufficient compression on that cylinder, you should do a compression test on it.. compression testers are not expensive, or you could just rent one.. I'll bet if you pulled the plug on that cylinder, and connected the wire to it, and grounded the threaded end, you'd see the spark jump the gap on the plug..

 

[angelugs]

Thanks for the input. I have pulled the plug, grounded it and looked for spark but saw nothing. Also connected a timing light to the non-firing cylinder plug and got nothing that way either. Haven't done a compression test but at this point I see no reason to do so.

 

[Amvcane]

Do you have a copy of TM1591? Section 240-20-38 to 240-20-44 covers everything you need to diagnose your symptions. I’m not sure how to post pages from a pdf.

 

[Amvcane]

I’ll try


They are not in order.

 

[radios1]

this reminds me of the 3 cylinder ignition module for an outboard boat engine they wanted $300 for.. nuts.. there's only $20 in parts in it!!. I took it apart, reverse engineered it, made a new circuit board, and it worked fine. it used a cheap fiber board, which arced over, and made a carbon trail, I used a fiberglass board, and gave it extra spacing. they used coils under the flywheel to make 400Volts, which went to the ignition module, water and high voltage don't mix.. anyway, you might be able to find a used module somewhere cheaply.. although it's possible to replace this junk with an aftermarket CD ignition system at a cheaper price, for someone that knows how to wire it..

 

[angelugs]

After talking with a few John Deere repair people who agreed that it SOUNDED like a bad ignition module, I broke down and bought one. Anyone want to buy a new ignition module? Yep, that isn't my problem. So I'm going back to page one and going through the troubleshooting steps looking for the problem. Don't really know anything I can ask to help me out. Just thought I'd post an update.

 

[radios1]

After talking with a few John Deere repair people who agreed that it SOUNDED like a bad ignition module, I broke down and bought one. Anyone want to buy a new ignition module? Yep, that isn't my problem. So I'm going back to page one and going through the troubleshooting steps looking for the problem. Don't really know anything I can ask to help me out. Just thought I'd post an update.

is the ignition module getting full voltage? is it getting a proper signal from the crank sensor? how about a kill wire, is that causing the problem?. and does the ignition module fire a spark coil? is so, is THAT good?.. I don't have wiring diagrams for this..