CKP Sensor Synch Error EFI - Harley Davidson Forums: Harley Davidson Motorcycle Forum

Zelrick · 12-03-2012, 08:48 PM

I was on my way to work today and stopped off at Schlotzkys to get a Rubin. When I came out my bike, 2011 FXDF, cranked for several seconds and did not start. I cycled the ignition and it started, though reluctantly, it popped and hissed through the breather first (it's been doing that a lot lately) . I checked the DTC codes and came up with P0734 CPK sensor Synch Error EFI.

I've been fighting with the local dealership for 3 months now over excessive vibration, the they claim is "normal Dyna". Could the crank position sensor be causing it, yet not be throwing a code, till now?

I didn't clear the code and plan on taking it to another dealer, but it may be a few weeks before I can get it there, so another question is how dangerous to the engine is it? What are the chances of it leaving me stranded? (I remember the CPS went out on my old Eclipse and it was a catastrophe, motor made all kinds of unique and disturbing noises.)

Bike is a 2011 FXDF
Stage 1 with all SE parts
Tuned with a Power Vision from Fuelmoto.

The motor has been run 4 times since the original code popped with no reoccurrence.

Thanks for any help.

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Dave63 · 12-04-2012, 05:43 AM

You could pull the sensor yourself to check to see if there's a piece of dirt stuck to the end but the symptoms of the sensor going bad are usually different. I do believe its related perhaps in the plug or wiring. Leave the code, inspect the wiring and plug and do a "wiggle test" on the wiring and plug" with the bike running. Not sure if this is your vibration issued but it certainly needs to be addressed.

SCHMIDTYS · 12-04-2012, 05:53 AM

The CKP didn't set the code the ECM did. There's any number of things that will cause that code. What's happening is the CKP is miscounting the teeth on the left flywheel. A pop back out of the intake (backfire), a plug that fails to fire or any ignition glitch for one engine revolution can cause the CKP to miscount and then the ECM sets that code.
If everything else, plugs, wires etc. check out I would suspect the Power Vision.

SCHMIDTYS · 12-04-2012, 05:56 AM

One more thing, check the battery connections and voltage. Low B+ can cause ignition problems. Your battery should show at least 12.8v static.

Zelrick · 12-04-2012, 06:06 AM

Thanks for the info guys. I'll get to checking things out.

Curious as to how it could be the Power Vision? All it does is allow me to flash tunes. I leave it on the bike as a gauge cluster to show RPM, engine temp and such.

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SCHMIDTYS · 12-04-2012, 06:09 AM

I was thinking the thing from FuelMoto was a fuel management system. So what kind of fuel management system is on your bike ???

Zelrick · 12-04-2012, 06:51 AM

The Power Vision is a "tuner" but, like the SE tuner it flashes the ECM with the new tune and doesn't have to be left on the bike. I do leave mine on the bike because it's screen can be used like a gauge cluster.

http://www.dynojet.com/PowerVision/

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SCHMIDTYS · 12-04-2012, 07:08 AM

Gottcha. I just checked their website. I'm not real familiar with the Fuel Moto products. I wasn't aware H-D gave any aftermarket company access to their ECM programming.
Now if you would have said PCIII that would have raised a big red flag.
Again, the battery connections and static voltage would be suspect.

Zelrick · 12-04-2012, 02:37 PM

Thanks again guys, off to work for now I'll get to investigating tomorrow.

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Zelrick · 12-06-2012, 05:27 AM

Checked every thing and then some, all seems ok. So, and I called a different dealer and will be getting the bike there as soon as I can. It's still under warranty and hopefully these guys are better.

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