Hello all! This is my first post on the forum and before I have posted this I made sure to check all other previous forums, cant seem to find anyone who has had the same problem I am having, so here we go...

I have had great luck with my Jap bikes, but I purchased a Harley because in less than 3 months I will be taking an American road trip, coast to coast, and it seemed more appropriate to do on a Harley. I spent more money than I felt comfortable spending and purchased a 2004 Road King Classic. 96ci with big bore kit. Thundermax fuel injection. Rinehart exhaust.

Since the day I brought it home 5 months ago, it has had an intermittent no start. Seems like 1/3 of the time it will start, and the days it does start, it will continue to start that entire day. Days it will not start, there is just no hope of getting it to run other than walking away from it for a few days. When the bike does not start, it cranks strong and it will do so until the battery dies. I keep the bike on a tender at all times. While it is not starting, I pulled the plugs out and connected them to wires, they spark against the motor, so I have spark. I noticed the plugs also smell of fuel, and I hear the pump kick on so I would guess I have fuel. I do have compression as well. Every dozen revolutions or so I will get a huge backfire.

I pulled codes 117 and 118 for coolant temp sensor, I replaced that and the codes went away, but the problem remains.

Took it back to dealership and they replaced a battery. then took it back again and they said new battery had a bad cell, so they swapped it out. still have this problem. while cranking the volts drop down to 8, I am not sure if this is a problem or not, but the new battery passed every load test.

please help if you have any idea what I should check for next, dealer is getting attitude with me and tellin me they cant look at it til next month, I am leaving for the ride of a lifetime in less than 3...

 

8 Volts cranking is a problem. I'm pretty sure the ECM shuts down at this level....so starting issues.

Are you measuring across the battery terminals?

You either have another bad battery, or a bad connection. Verify all power and ground connections.

 

I though this may be my issue as well but when I went to the dealership and the head tech told me that it is perfectly normal for the voltage to drop this low while cranking as long as it returns to above 12 when cranking is stopped. @ defective new (interstate) batteries in a row?

 

Does anyone know how many volts the computer requires?

 

No I don't, but electronics are very picky things, they don't like change! My EFI BMW wouldn't start if the battery was down on volts, even if it turned over OK.

 

Not sure how it ended up in exhaust category, but i couldn't delete it. I picked it up in a new tread and figured out that this was all due to my battery. My battery tested good and was new but when i added a booster pack, the bike fired right up.

 

Reminds me of the old Honda 750 SOHC bike. No start with the electric starter and one kick without it. Very common. 8 volts is too low for the ECU I bet. And the engine is drawing tons less via the starter to crank over with the plugs out so don't bet on them firing when screwed in!

 

Check for loose cables ............. grounds bolted down good!!!!

 

Just a thought....I had a sorta similar issue with my own 2004 Road King Classic. My bike would at time idle high and stall out. And then starting was rough at times too. AND I PULLED THE 118 CODE AS WELL. The 118 code refers to the engine temp sensor. It is about a $40 part and pretty simple to replace. Idk how much you know about this sensor, but it acts sort of like a choke would on a carb. On a cold start it tells the ECM the temp of the engine and then the ECM know to add more fuel to the a/f ratio-just like pulling the choke. If you're sensor is bad it could be telling the ECM that the engine is really cold, so its dumping lots of fuel and flooding. I replaced mine this past weekend and so far so good!

 

I replaced the sensor for good measure when i saw the code, but at this point in time, i think it was a false code from voltage dropping. Ive seen bad batteries do all sorts of weird things to electronics.