2003 FXDL w/ 11K miles.
Problem: Starts and runs on front cylinder only. No spark at all from coil on rear cylinder wire.
History: This happened a month ago for the first time.
The trouble light was indicating a problem. I erased the trouble light before finding which problem # it was.

Removed the battery, which was 5 years old and weak. Replaced with new battery. Bike started right up on both cylinders! No trouble light indicated.
Rode it for the following 2 weeks. After engine warmed up, it would momentarily die while riding, like the ign switch had been bumped off and then on. Reminded me of running an engine that had not warmed up yet. This continued and then gradually began to go away.

Started the bike this morning.
Started on front cylinder only again.
No fire from the rear wire.
Wire connection good on both ends.
Spark plugs are good (makes no difference if there is no fire )
No trouble light to indicate a problem either. (What I am saying is the trouble light functions normally and does not indicate a problem.......... but the bike is running only on the front cylinder, so that is somewhat of a problem)

So, I either have a bad coil or a bad ignition module.
In my experience the coil never goes out.
So is there anyway to bench test it?

Anyway to test the module? I do not have one of those $$$$ Scanalyzer instruments, just a volt/ohmmeter and the factory manuals. Is it even possible to purchase the Scanalyzer?
Anybody got any ideas?
Thanks........pg

 

2003's the ECM performs the ignition function and you do not have a cam position sensor or ignition module but don't feel like digging up my notes so some of that statement may be wrong but it's FYI anyhow. Scanilyzer is proprietary to HD as far as I know and not available to general public and would cost a small fortune. Yes, coils CAN go bad! There are tests for the coil but all are too numerous to write down in even two long threads; tests are located in Section 8, Electrical, of the service manual. Two of them I will list since it checks both coil primary and secondary windings (either one fails will result in what you describe being rear cylinder does not spark)= Check continuity of one spark output (with cables out) to the other: should read continuity (about 2.5-3.1 ohms). Next remove the pink lead, attach the red multimeter lead to the coil, black to ground, and turn the key on: should read 12VDC. Or, if you want to check resistance on the last one instead of voltage, it will read 10,000-12,500 ohms but is hard to get probes into coil mounted on the bike: voltage is easier to do. If either does not read as indicated, coil is bad. If these read okay, I would suspect the ET sensor in the absence of trouble codes since, when it reads thermistic resistance, would shut down the rear cylinder as heat management response, without necessarily throwing a code. The coil is single fire (one spark being a "wasted" spark) so if coil is good, must be another reason besides ECM, coils, wires, plugs, is my logic.

 

Robzuk97.........
Thanks for the reply, but.......
I do not think I can agree with you on the coil being a 'wasted spark' system (like my old Sporty) where both fire at the same time, everytime.

If that were the case I do not think I would see the coil outlets designated as front (lower wire) and rear (upper wire). Also, if that were the case then I could swap spark wires and the rear cylinder would fire and the front one would not. And this on an engine that will not fire at all if both spark plugs are removed? Talk about letting electronics run the show! Thank the gods it has a carburator at least, and not more electronic crap with injectors.

I have done all of the tests in the manual I can with a voltmeter.
What happened the first time it did this, the battery read out as being at 11.9 volts. The wire connecting to the coil read 10.7 volts.
The battery was getting low to start the engine, so that was the reason I changed it out. After doing that, the battery reading was 13 volts. The reading on the coil wire was 11.7. I know not why the difference.
I cranked the engine and both cylinders fired right up and the bike ran fine for a couple of weeks.
So, I guess I just have to start looking for the cause of the problem.

Yeah, coils can go out.....but, I have been working on two wheelers since 1957 (and on many, many different brands at that) and you know how many coils I have seen go bad?
The answer is Zero. None, in 52 years!
The local HD dealer does not have a coil in stock. At $98 each, I think I know why (read that as not likely to be needed)............ pg

 

Have you checked for a weak or failing stator? Did you check all the wiring connections to the VR?
BTW, if you have time to get parts check with Zanotti HD on line (20% off).

 

To test the coil/ignition you would need a diagnostic scope, i.e. oscillascope. Your best bet would be just find a shop with a scope and pay them to diagnose it for you.

 

When I had reached 1500 miles on the bike (no warranty, another story)the battery went dead. Having all of the factory manuals, I checked out the system.
The results indicated a shorted stator. I took it to a Harley dealer (first time I ever did that) and told them the problem, and that my tests had indicated the stator may be shorted.
They spent 2 hours working on it and then told me there was no problem, but he had charged up the battery. He also charged me $$$ for the service, which is fine.
Next week I have another dead battery. Did the same test again and the results were a shorted stator.
I returned to the dealer and managed to get a full refund, minus $17 for the battery charge the week before.
Was I pissed? You bet I was. Incompetent kids working in that shop either did not know how to check it out, or were just plain lazy.
I will never deal with this dealer again.

I went straight to the other HD dealer in town and bought a $107 stator, got home, removed the primary cover and put it on. Problem fixed. The stator has a burned spot on the assembly where it shorted out.



So no, it is not the stator. The stator is part of the recharging system. Lack of fire is part of the ignition system.
No offense meant to you, but I am beginning to wish I had not asked the question here on the forum. I hoped there was some certified Harley tech looking on who might have a suggestion........... pg

 

http://www.picoauto.com/waveforms/Ig...ary/wave2.html

I can well appreciate that you would like some simple test with a multi-meter to test your coil/ignition, but it is a dynamic system. You have to see it over time to diagnose it.

 

Well, the time is certainly passing and I am watching it.
This morning I had the coil off and checked the primary and secondary resistance. All was OK.
I also checked the battery voltage.
It was 12.3 volts.

I unplugged the #83 connector to the coil and checked voltage to the coil. It was 11.3 volts. So it is not the same as the battery.
This is nothing new. Ever since I have had this problem over a month ago, this lead is always 1 volt below that of the battery. (???????)
So I plugged the connector back onto the coil.

Anyway I turned the engine over and saw both wires are now firing.
Cranked it up again and it runs just fine on both cylinders!
This is the second time this has happened and I be danged if I can figure out what is causing this.
Anyway I am riding again but I do not know for how long. Twice the bike has started up and run on only the front cylinder.
Both times the engine was stone cold and it happened in my driveway, rather than out on the road somewhere. How lucky can I get?
So I am tempting the Gods from here on out.
I am wishing it would just quit and not come back running normal so that I can find the problem....... pg

 

I see you're in Houston, so I looked at the weather; looks like it's fairly dry and not too cold out here... So anyway, I'm wondering what the connector and contact looked like when you disconnected it? Any corrosion or junk? I had a problem with my '07 SG killing the battery, and there was corrosion on the coil connections. Cleaned them up and put some grease on them and haven't had a problem since.

 

Yes, Houston weather is as good as it ever gets today. 68°F and RH is 24%.
The coil connection was absolutely clean on both the plug side and the coil side. You may have gotten water in there by washing the bike, but on the other hand it would be difficult because of the design of the plug in.
Grease will prevent any more corrosion.

As I said earlier in this post, my battery started to run down when the bike was quite new
I found the reason was the stator had shorted out. It would startand run for about a week between needing to recharge the battery............. pg