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Trouble with rear cylinder

Police Harley

New Member
Diagnostic code is "No rSP"
I thought to myself, self, that could mean no rear cylinder pressure.

Scenario... caught in traffic on freeway due to wreck, 1+ hour at 10 mph...(not good for air cooled bike) check engine light comes on, goes off, comes on, goes off.
Ride to cool engine off after traffic, light comes on when I get on throttle, stays on for 10-15 secs goes off.
Smart Soldier thinks, time to stop at HD in winchester.
Yep smart move...heat protection mode stuck. Dealer clears it and test drives it. GTG.
On way home, wicked vibration, not smooth.
Smart me pulls off and does diag (watched the guy at dealership:D), code No rSP, can't get it to clear.
Common sense says, self, check plug wire, plug etc. Found plug wire loose and plug not tight....doesn't seem right :(, borrow spark plug wrench and since plug down and ensure plug wire set right. GTG ride home uneventful except code won't clear. (this was all last weekend)
Went to local recommended shop and they clear code with reader, look at the stuff I did, confer with another dealer and say GTG.
Bikes running great, smooth V-Twin vibe.
Go on ride today, no problems until I get on the freeway to come home(about 190miles into ride), feel that vibration again...:(
Get home and diag.. same code, but plug and wire are tight.
:unsure
Do some digging and see that this is not a new occurrence with the rear cylinder in Harley's.....however......
Could this really be a plug or injector?
When I work through the diag settings,
P= none
S= no rSP
S= none, then gives a Pn and numbers
ST= none, then give Pn and digits
t= none, then gives same Pn and St.

Thinking me says these are part numbers which may need to be replaced...am I on the right track?
I would be very grateful if someone could provide a bit of guidance and support as this is my first Harley after 20+ years of riding.
I really like the bike and have some resto plans in store for it, but don't want it to be a money pit, have to sell and go back to gold wing or yamaha.

PMCS is habitual being in the military, and I have no fear of getting hands dirty, but this is beginning to :bigsmiley19:
 
No rSP is not a trouble code. It means "No response" from the device (speedo, ecm, TSSM etc)

The part numbers you see only represent the device on the communication buss. They do Not represent what is wrong or should be changed. Local dealer cleared the code? What was the code.
You can't have both a S=no response and S=none. S=none means there WAS a response.

What does "GTG" mean.
 
Hoople,
The code cleared was P1356 No Combustion in Rear cylinder.
I cross referenced this with the chart on this site and it was correct.

GTG is mil chat for Good to Go.

any other suggestions other than, change plugs, wires, check injector wiring, and the other things I've read.
I will start tomorrow with the changing of the easy stuff. hopefully this used police unit doesn't have a bad cylinder.
Spark plug in it now is light brownish colored and the cylinder is heating up so it's firing.
Could it be the ECM that controls the heat protection mode?
 
A bad cylinder is not likely to come and go. Anything on secondary side of coil (plug wire, spark plug, coil itself) could cause that code. Do the easy things first. You may be GTG after that. A compression test and leakdown of both cylinders will tell you what mechanical condition your engine is in. You did not say what mileage you had on the engine.

It would be very remote that the ECM is bad.
 
I agree with Hoople on his last post. Modern engines use Carbon filled plug wires which have a measured amount of resistance by design. If you have a plug wire about to go, usually it shows up under higher temps. Also check & pay attention to both ends of the plug wires the one on the plug & the end going to the coil... check for corrossion & a good tight fit & be sure to use dieelectric grease on the ends. I would recommend taking a resistance reading (The Harley manual will tell you what they should be), but by the time you take it off the bike & it cools off it may read OK because it sounds like its breaking down when it gets hot. (2) Also there are specific readings of resistance for the coil, but Id check the wires first.
 
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