I'm stumped
Thread Starter
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4th Gear
Joined: Feb 2021
Posts: 8
Likes: 0
From: OH
I'm stumped
Got an '03 FLHTC, carbureted. Had it 3yrs now and has ran great. As of last Oct it stranded me twice. Rode for several hours then heading home it acted up. Left a stop sign 1st gear, 2nd. 3rd accelerating towards shifting to 4th and it started running sluggish like it was only running on one cylinder. Pull in the clutch and the engine shuts off. All electrical stays on. Got it towed. Mechanic I used to work with told me to check the connection for the ignition. Found corrosion and cleaned it all up. Bike ran like a champ. A month later the same **** happened. Started getting cold so I said **** it. Well I'm starting to get it ready for spring and I'm checking things out. I replaced the ignition, coil, plugs and wires, installed a new 50 amp circuit breaker. Cleaned up all the grounds in the battery compartment. Took it out for a ride and I made it maybe 30 miles and the same **** happened. Took me 1 1/2 hrs to make it back to my garage. It went 10 miles then shut off. Had to sit and let it "cool down" before it would start up. Did this about 7 times before I could get back to the garage. Can ANYONE tell me what I'm overlooking??!!
Stellar HDF Member
Joined: Mar 2020
Posts: 2,236
Likes: 2,158
From: West Coast
Without seeing it and running some tests, sounds fuel-ish. WAG: Crap in tank starving the petcock (leaf, crud, liner, water)? the cool down period could be letting obstruction float away from pick up?
Signs of clogged fuel line is it generally craps when under power as it drinks faster than supply. Will idle fine and often cruz fine.
on edit, sticky float or float needle?
Signs of clogged fuel line is it generally craps when under power as it drinks faster than supply. Will idle fine and often cruz fine.
on edit, sticky float or float needle?
Seasoned HDF Member
Joined: Aug 2006
Posts: 24,496
Likes: 30,782
From: Pennsylvania
As this is your first post, welcome to the forum.
If it was a Sportster I would say it is the ignition control module (ICM) Does your bike have an ICM in the nose cone? May be worth while to test like below.
http://sportsterpedia.com/doku.php/t...k:evo:engctl01The 1998-2003 Non-Sport model used an integrated ICM on the Sensor Plate (which was still located in the 'nosecone' behind the round cover) and was still a Dual-Fire Spark System.
These OEM modules had a high failure rate, apparently due to the high heat in their mounting location. The MoCo stopped providing replacement units as soon as they were allowed. The only current choice for replacement is aftermarket versions (such as the Ultima brand discussed HERE or the equivalent from another brand).
The ICM may fail with a number of different symptons, with some randomness. The bike may refuse to fire even though the starter will turn the engine over. Some riders report that flicking the RUN/STOP switch (which sends power to the ICM and the coil) several times will sometimes allow the bike to fire up. The ICM may also fail due to heat even though it fired up cold. In this case, once the engine cools down, the ICM may allow the engine to fire up again. This can be extremely frustrating as the bike will randomly stop while riding. Various other, less common, symptoms may occur from a failing nosecone ignition module (misfiring, backfiring, etc.).
There are two methods of testing the ICM relative to heat failures. Method One makes the ICM fail when the engine is cold, while Method Two tries to make the ICM begin functioning again after it has failed due to heat.
Heat Test - Method #1 - If the bike usually fires when cold but dies when warm/hot, test the ICM with the engine cold. With a cold engine, use a hair dryer to blow heat on the ICM (in the nosecone) before attempting to start it. After it's warm, see if the engine fails to start due to the spark missing or intermittent.
Heat Test - Method #2 - Once you have a running failure from heat, use 'cold spray' to quickly cool down the ICM (in the nosecone). If the ICM has failed due to heat, this test will check if it will begin to produce a spark again after being cooled down.
Sometimes, these two methods can be used in combination to create & resolve a failure condition, although heat related problems can still be hard to diagnose/resolve. The same procedures can be used to test the ignition coil for heat failure.
If it was a Sportster I would say it is the ignition control module (ICM) Does your bike have an ICM in the nose cone? May be worth while to test like below.
http://sportsterpedia.com/doku.php/t...k:evo:engctl01The 1998-2003 Non-Sport model used an integrated ICM on the Sensor Plate (which was still located in the 'nosecone' behind the round cover) and was still a Dual-Fire Spark System.
These OEM modules had a high failure rate, apparently due to the high heat in their mounting location. The MoCo stopped providing replacement units as soon as they were allowed. The only current choice for replacement is aftermarket versions (such as the Ultima brand discussed HERE or the equivalent from another brand).
The ICM may fail with a number of different symptons, with some randomness. The bike may refuse to fire even though the starter will turn the engine over. Some riders report that flicking the RUN/STOP switch (which sends power to the ICM and the coil) several times will sometimes allow the bike to fire up. The ICM may also fail due to heat even though it fired up cold. In this case, once the engine cools down, the ICM may allow the engine to fire up again. This can be extremely frustrating as the bike will randomly stop while riding. Various other, less common, symptoms may occur from a failing nosecone ignition module (misfiring, backfiring, etc.).
There are two methods of testing the ICM relative to heat failures. Method One makes the ICM fail when the engine is cold, while Method Two tries to make the ICM begin functioning again after it has failed due to heat.
Heat Test - Method #1 - If the bike usually fires when cold but dies when warm/hot, test the ICM with the engine cold. With a cold engine, use a hair dryer to blow heat on the ICM (in the nosecone) before attempting to start it. After it's warm, see if the engine fails to start due to the spark missing or intermittent.
Heat Test - Method #2 - Once you have a running failure from heat, use 'cold spray' to quickly cool down the ICM (in the nosecone). If the ICM has failed due to heat, this test will check if it will begin to produce a spark again after being cooled down.
Sometimes, these two methods can be used in combination to create & resolve a failure condition, although heat related problems can still be hard to diagnose/resolve. The same procedures can be used to test the ignition coil for heat failure.
Thread Starter
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4th Gear
Joined: Feb 2021
Posts: 8
Likes: 0
From: OH
Is there a specific test on the crank sensor? I pulled it out to see if there was any debris on it, which there was none.
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Thread Starter
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4th Gear
Joined: Feb 2021
Posts: 8
Likes: 0
From: OH
As this is your first post, welcome to the forum.
If it was a Sportster I would say it is the ignition control module (ICM) Does your bike have an ICM in the nose cone? May be worth while to test like below.
http://sportsterpedia.com/doku.php/t...k:evo:engctl01The 1998-2003 Non-Sport model used an integrated ICM on the Sensor Plate (which was still located in the 'nosecone' behind the round cover) and was still a Dual-Fire Spark System.
These OEM modules had a high failure rate, apparently due to the high heat in their mounting location. The MoCo stopped providing replacement units as soon as they were allowed. The only current choice for replacement is aftermarket versions (such as the Ultima brand discussed HERE or the equivalent from another brand).
The ICM may fail with a number of different symptons, with some randomness. The bike may refuse to fire even though the starter will turn the engine over. Some riders report that flicking the RUN/STOP switch (which sends power to the ICM and the coil) several times will sometimes allow the bike to fire up. The ICM may also fail due to heat even though it fired up cold. In this case, once the engine cools down, the ICM may allow the engine to fire up again. This can be extremely frustrating as the bike will randomly stop while riding. Various other, less common, symptoms may occur from a failing nosecone ignition module (misfiring, backfiring, etc.).
There are two methods of testing the ICM relative to heat failures. Method One makes the ICM fail when the engine is cold, while Method Two tries to make the ICM begin functioning again after it has failed due to heat.
Heat Test - Method #1 - If the bike usually fires when cold but dies when warm/hot, test the ICM with the engine cold. With a cold engine, use a hair dryer to blow heat on the ICM (in the nosecone) before attempting to start it. After it's warm, see if the engine fails to start due to the spark missing or intermittent.
Heat Test - Method #2 - Once you have a running failure from heat, use 'cold spray' to quickly cool down the ICM (in the nosecone). If the ICM has failed due to heat, this test will check if it will begin to produce a spark again after being cooled down.
Sometimes, these two methods can be used in combination to create & resolve a failure condition, although heat related problems can still be hard to diagnose/resolve. The same procedures can be used to test the ignition coil for heat failure.
If it was a Sportster I would say it is the ignition control module (ICM) Does your bike have an ICM in the nose cone? May be worth while to test like below.
http://sportsterpedia.com/doku.php/t...k:evo:engctl01The 1998-2003 Non-Sport model used an integrated ICM on the Sensor Plate (which was still located in the 'nosecone' behind the round cover) and was still a Dual-Fire Spark System.
These OEM modules had a high failure rate, apparently due to the high heat in their mounting location. The MoCo stopped providing replacement units as soon as they were allowed. The only current choice for replacement is aftermarket versions (such as the Ultima brand discussed HERE or the equivalent from another brand).
The ICM may fail with a number of different symptons, with some randomness. The bike may refuse to fire even though the starter will turn the engine over. Some riders report that flicking the RUN/STOP switch (which sends power to the ICM and the coil) several times will sometimes allow the bike to fire up. The ICM may also fail due to heat even though it fired up cold. In this case, once the engine cools down, the ICM may allow the engine to fire up again. This can be extremely frustrating as the bike will randomly stop while riding. Various other, less common, symptoms may occur from a failing nosecone ignition module (misfiring, backfiring, etc.).
There are two methods of testing the ICM relative to heat failures. Method One makes the ICM fail when the engine is cold, while Method Two tries to make the ICM begin functioning again after it has failed due to heat.
Heat Test - Method #1 - If the bike usually fires when cold but dies when warm/hot, test the ICM with the engine cold. With a cold engine, use a hair dryer to blow heat on the ICM (in the nosecone) before attempting to start it. After it's warm, see if the engine fails to start due to the spark missing or intermittent.
Heat Test - Method #2 - Once you have a running failure from heat, use 'cold spray' to quickly cool down the ICM (in the nosecone). If the ICM has failed due to heat, this test will check if it will begin to produce a spark again after being cooled down.
Sometimes, these two methods can be used in combination to create & resolve a failure condition, although heat related problems can still be hard to diagnose/resolve. The same procedures can be used to test the ignition coil for heat failure.
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Road Master
Joined: Jun 2014
Posts: 967
Likes: 588
From: Arizona
Originally Posted by Noname3412
Is there a specific test on the crank sensor? I pulled it out to see if there was any debris on it, which there was none.
Tourer
Joined: Oct 2016
Posts: 325
Likes: 45
From: Upstate SC
FWIY, have a look to the diaphragm in the carb. Back when I had my 03 carbed I had a similar problem. It would run but barley enough power to get out of its way, ha. It was the diaphragm boot in the carb that had a pin hole in it. Replaced and no further issues.
