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Steve
Steve, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 6943
Experience:  30+ yrs. experience, MMI, HD technician, HD early, engine rebuild/performance, bike builder, kit bike program manager, CCI 2001-2004
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how to test iignition module on a 2003 harley sportster

Customer Question

how to test iignition module on a 2003 harley sportster
Submitted: 4 years ago.
Category: Motorcycle
Expert:  Steve replied 4 years ago.
Welcome. Thank you for choosing Just Answer.

what model sportster do you have?

why do you need to test the ignition?

tell me everything you can.
Steve
Customer: replied 4 years ago.
xlh 1200
Expert:  Steve replied 4 years ago.
we can get through this much faster if you answer all my questions.

WHY do you feel you need to test the ignition module?

Steve
Customer: replied 4 years ago.
While riding .. Stars backfiring.. Cutting out and dies... After cooling will start
Expert:  Steve replied 4 years ago.
the problem may be the ignition or the charging system.

with a multimeter, measure the battery voltage with the engine at about 2,000 rpm, to check the charging system.
we need to eliminate this possibility before we proceed.
let me know what you find.
Steve
Customer: replied 4 years ago.
13.8
Customer: replied 4 years ago.
Also getting high resistance on the secondaris on the coil.. Running 13,500 ohms... Could this be coil breakdown.. Normal on primaries
Expert:  Steve replied 4 years ago.
Thank you.

your coil sounds ok.

13.8 vdc is a little low, but in spec.
this may indicate a potential failure of your charging system or a problem with your battery.
this is something you will have deal with later.

you need to be aware the intermittent electrical and/or ignition issues are very difficult to diagnose.
your symptoms indicate a heat related failure, which could be caused by more than one component.
the possibilities include the coil, the BAS (bank angle sensor) and the ignition module.
there is no bench test for your ignition module.

if the bike had fallen over before this started or if it bumpy roads are involved, the BAS would be the likely cause. it is located in the TSM. the BAS disables the ignition when the bike falls over and is also known to fail whenever it feels like it. the BAS can be bypassed by removing the green/gray wire from the TSM and grounding it. if the failure continues, this is not your problem.

if the bike has not fallen over or bumpy roads is not an issue, heat related failure of the coil or ignition module are likely.
you should inspect the coil for cracking or physical damage. if none are found, the ignition would be the most likely cause.
it is located in the gearcase (cam) cover on the right side of the engine, behind a round HD medallion riveted to the case.
you will have to drill the rivets to inspect or replace the module.
before replacing the ignition module, the BAS should be bypassed to ensure it is not the cause.
if it is not, the ignition module is the only component left. you can choose from HD and aftermarket modules if replacement is required.
let me know if you would like a recommendation.

that said, everything stated above assumes there are no wiring issues on the bike.
you should verify the ignition wiring before doing anything else. if you are losing ALL electrical power, not just ignition, the main circuit breaker is a possibility and should be replaced.
let me know if you need more help.
Steve
Customer: replied 4 years ago.
Testef bas with magnet.,, it shut down,, reset and started rite up...
Customer: replied 4 years ago.
Testef bas with magnet.,, it shut down,, reset and started rite up...Could the bas stil be bad
Expert:  Steve replied 4 years ago.
anything is possible with the BAS.

as I stated above, the only way to determine if the BAS is the problem is to remove the green/gray wire from the BAS connector and ground it. if the problem persists, the BAS is not your problem.
if the BAS disables the ignition, it is suppose to generate a diagnostic code.
if you have no codes, it is probably not your problem.
Steve

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