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Running on one cylinder

Ok, went to gas station 1.5 miles away....running good. Shut down filled up, started and.....rear cyl no combustion...threw a code..rear cyl no combustion EFI code....

Thoughts....
 
P1356 => no rear Ion current sensed under steady state engine load. This is not a code that is detected during start up. That code can stem from two reasons. Of course one is from no combustion in that cylinder due to no fuel, no compression etc. The other is from an open secondary circuit in the coil.

But you said you DO have spark (have seen spark) in the rear circuit. If you still have spark, my guess would be you have no fuel being injected. I am assuming a compression test of the engine would yield somewhat equal pressure from front to rear. With that said, my guess from a thousand miles away,, would be injector pig tails, injector itself, severely reduced fuel pump pressure, lack of ground shot from ECM for that injector,,, something along those lines & in that order.
 
Hoople said:
P1356 => no rear Ion current sensed under steady state engine load. This is not a code that is detected during start up. That code can stem from two reasons. Of course one is from no combustion in that cylinder due to no fuel, no compression etc. The other is from an open secondary circuit in the coil.

But you said you DO have spark (have seen spark) in the rear circuit. If you still have spark, my guess would be you have no fuel being injected. I am assuming a compression test of the engine would yield somewhat equal pressure from front to rear. With that said, my guess from a thousand miles away,, would be injector pig tails, injector itself, severely reduced fuel pump pressure, lack of ground shot from ECM for that injector,,, something along those lines.
Click to expand...
+1

Ground shot meaning...High side of an injector is connected to a 12vDC supply. The ECM fires an injector by pulling the low side of the injector to ground.

My recent experience shows that, either my TFI interferes with ECM detection of open injector connections, or the lines are not continuously monitored by the ECM, possibly polling those lines on a periodic basis, or requiring several cycles of problem before throwing an injector-related code. I have had a problem with an intermittent injector wire, and it had to really be running bad, for a significant period, before a code was finally thrown, and it cleared up for a significant period, before the code went to historic.

Ion current flows across the spark plug electrodes after compression and ignition of cylinder gases. This current is monitored by the ECM, for the primary purpose of anti-knock correction. Sometimes non-HD plugs or wires can cause the code you mention, if no symptoms. But, since you are having symptoms, you likely have a real problem. Lack of spark or fuel can cause the code, and since they are both delivered at the same timing, distiguishing which one can be quite difficult without additional info. Hoop's got it pretty well layed out as to where to look. My vote is also on intermittent injector wires, at the injectors. Injectors and ECMs are pretty robust. If not the wires, injector next on the list.

Enjoy,
Rich P
 
Ok, I have learned much. Well it appears that the coil is the culprit. Intermittent operation of the r coil when hot. I verified that the injector was firing using the "stick" method or listening with a mechanics stehoscope. So I went back and rechecked the plug wires and spark and found that I had none at the rear cyl? When I had spark last night it was part of the intermittent part...I should have known since I was not impressed wit the flimsy spark. So after continunity checks from the ECM to the coil ION sens, R shot were good so a coil was purchased and installed and all seems to be back to normal. Thanks for the much needed help and I have learned a lot about the FI on this bike all previous bike were carb.

Rich thanks for explaination of the role of ION sens....and Hoople for the more indepth explaination of the code....had i not rechecked for spark that would have sent me back to the coil.

Thanks again all
 
Superb. This stuff is tough to locate, especially when intermittent or marginal. Take her out and ride her like you stole her. Make sure you got it.

If I might respectfully suggest...a small contribution to the site might be appropriate (totally voluntary). There is a "Donate" menu item in teh menu bar, above. A site as valuable as this one has costs to keep it available. I just made my 1st contribution, since I have been helped quite a bit myself, since I discovered the site in '09. Again, just a suggestion...in any case, it is gratifying to see another issue in the can.

Enjoy,
Rich P
 
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