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P.J., Technician
Category: Motorcycle
Satisfied Customers: 750
Experience:  10 years as a mechanic and fabricator in a privately owned, local, custom bike shop.
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I have an 03 flhtcui starts the first time the you can shut

Customer Question

I have an 03 flhtcui starts the first time the you can shut it off turn the ignition right back on the engine cranks but wont start let it sit for ten minutes and it will start and run but if you shut it off it will arin
Submitted: 1 year ago.
Category: Motorcycle
Expert:  P.J. replied 1 year ago.
A little more information may be helpful. After the first start and shutdown do you hear the fuel pump priming during the second attempt to start the bike? Do you have a fuel injection tuner installed or any other modifications to the ECM or engine? Have you checked whether or not spark is present when the bike will not start?Thanks, P.J.
Customer: replied 1 year ago.
yes you can hear the fuel pump priming.
took power commander5 back out of loop, hooked ecm up direct.
do not have spark present until bike sits for 10 min. then i have spark and bike starts.
But if i try to restart it, no spark for another 10 min.
Expert:  P.J. replied 1 year ago.
Okay, thanks.
An odd problem for sure. Usually these types of problems are heat related but yours doesn't seem to be.
Either way, When no spark is present, the first check is of the crank position sensor. If you have a voltmeter available you can use it to check the sensor yourself.
The sensor is located on the left front of the engine case near the end of the oil filter. You'll want to first remove the single retaining bolt and then pull out the sensor and clean it. It is a magnet and collects metal debris which can interrupt the signal. Using the meter on the AC setting you'll connect the leads to the two wires leaving the crank sensor. It does not matter which meter lead connects to which wire.
While cranking, you should see 1 to 3 volts AC depending on cranking speed. If you don't see a voltage produced then it indicates a bad sensor and I'd suggest a replacement.
The simplest way to connect the meter to the sensor wiring is to chase the wiring down under the regulator, along the right side frame rail, and under the right side cover and unplug the connection in the wiring. Unless you have small alligator clips for your meter leads you may need another person to crank the bike while you hold the leads.
Check this sensor and let me know what you find. If it reads good first and the bike starts I'd suggest testing it again when the bike does not have spark to compare the results.
Thanks, P.J.
Customer: replied 1 year ago.
Like I said, I already checked it. Went a head and installed a new sensor, still same problem. Checked coil, replaced it with known good one, have voltage at coil on power wire, while cranking. Tack registers 300 rpm while cranking, but still no spark. Wait 10 min. got spark...
Expert:  P.J. replied 1 year ago.
You already checked and replaced the crank position sensor? I apologize but I don't see that in any of your information above. If so, then you need to check the voltage on ECM pin #31 while using pin #10 as your ground. This check has to be done and recorded while cranking. You cannot see the maximum voltage voltage drop with a meter that does not record instantaneous voltage. The voltage needs to be 10 volts DC or above at all times. If it drops below this 10 volts DC at pin #31 then the ECM will not produce spark. Thanks, P.J.
Customer: replied 1 year ago.
wont be able to do the test till late today or tomorrow thanks
Customer: replied 1 year ago.
ok did the ck it only has 8.4 v while cranking
Customer: replied 1 year ago.
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Customer: replied 1 year ago.
ok new bat. have11.8-11.5 v same prob. starts first time wont restart still have same voltage while cranking
Expert:  P.J. replied 1 year ago.
If the voltage does not drop below 10 volts when checked between pin 31 (positive) and pin 10 (negative) then there are only a couple options left that can kill spark.
The bank angle sensor (located inside the turn signal module) can disable the ignition. If you don't have security you can unplug the TSM to check to see if the problem is solved. If so, you'll need to replace the TSM to get a new bank angle sensor.
One other issue is excess oil collecting in the engine case. This can disrupt the signal (actually the break in the signal) from being generated by the crank position sensor. It takes quite a bit of oil to cause this issue. You may be able to tell if you knew the oil level you had in the tank.
Beyond that, you're looking at a wiring (broken, shorted, or corroded) or ignition module (ECM) issue. You've changed about all the other components so I'm assuming they are all good. You're about to the point where a breakout box is required to diagnose further.
Thanks, P.J.

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