Codes with no Check Engine Light are Historic codes and the 131 and 151 are set during initial startup before the engine actually starts running. Code that are set during the times that the engine are running will give a Check Engine Light.
Historic codes are not harmful and are not a present condition of engine conditions.
So, yes! You can safely ignore these codes.

 

I get these codes only on first start up when the bike is cold then I clear them and they do not come back until it sits for a while and is started again. Aside from that&nbsp\\; I'm running a 2into1 with a ness big sucker I have no decel poping or backfiring it seems to run good.

 

Sorry I have to beg to differ.&nbsp\\; 131 and 151 cannot be set without the engine running.&nbsp\\; The engine must be running and the sensors have to be warmed up and active.&nbsp\\; Although it can occur as the sensors are warming up, but not with the engine off. Harley has chosen not to ever display the CEL for the O2 sensor codes...if they happen they go direct to historic.&nbsp\\; This is totally controllable within the ECM and is programmable by the MOCO.
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So I would not ignore these codes.
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If these codes&nbsp\\;are happening every time you cold start the bike, something is not right.&nbsp\\; My guess based on this symptom, the XIED is causing the O2 sensor to cross the enable voltage before the sensor is warmed up.&nbsp\\; The ECM then tries to go closed loop but the sensor is not ready and will not switch...and therefore sets codes.&nbsp\\;
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The XIED works by lowering the voltage output of the O2 sensor.&nbsp\\; During warmup, the ECM monitors the sensor voltage to determine when it is ready.&nbsp\\; The sensor starts at 5V and decays as it warms up.&nbsp\\; Once it&nbsp\\;crosses below a set voltage, the ECM assumes the sensor is ready.&nbsp\\; The IED will cause the ECM to think the sensor is ready earlier. I can see how this will cause issues with 131/151.
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&nbsp\\;I have found the XIED"S help a bit but not the over the top claims some make. depending on conditions 291 is not out of line. The bike is built to handel that.
The&nbsp\\; Xieds do what nightride says they will but some have attached claims to them nothing could live up to.
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Running a good 100% true sny oil in the engine is one of the best things you can do.
There are a lot of good ones out there.

 

291&nbsp\\;at the&nbsp\\;rear is not too hot and is as good as it gets. My 08 SG front 285 / rear 310.. Thats with Rineharts, Heavy Breather, and SERT MAP from Latus motors. If&nbsp\\;Throwing a couple of resistors in line with your&nbsp\\;02 cell richens it up enough to run good, lower AFR, and Lower head temp your doing all right.&nbsp\\;\\\\\\;
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Thanks for that explaination Aggie...&nbsp\\; I think I'm missing something tho...&nbsp\\; (Elec Eng here, so I love to troubleshoot ****, and my 08 SG is throwing the same codes with XIEDs)

Assuming no exhaust leaks...

So your saying the XIEDs are causing the ECM to think the O2 sensors are at the 'ready' voltage, which in fact they are at some higher voltage but due to the voltage divider we know that the XIED output is some % lower.

As the O2 sensor continues to warm, does the voltage decay to something 'too low' as the ECM kicks into closed loop mode? Wouldn't that throw a "sensor too rich" code?

I guess I'm not sure about the ECM interaction with the O2 sensors, how would it sense a 'too lean' event (too much voltage) with the XIED dividing down the voltage even further... unless, the O2 sensor "ready" voltage signal to the ECM is sufficiently high enough that it's greater than a 14.7 AFR signal, but then even without XIEDs you'd get that code... I can't figure out a way that the ECM would ever see anything but a lower signal / rich condition. Hrm. Help?

What I am missing / messing up?

Is there a good technical write up somewhere online about the Delphi EFI system?

 

Hmmm, according to Steve at Nightrider, the bike starts up in open loop mode (no O2 sensors involved) until the engine warms up. Then it switches over to closed loop. Therefore, the Xieds have no effect at cold start.&nbsp\\;
Did I miss something?
&nbsp\\;
JIm

 

Lt James...Lean is low voltage....rich is high.
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Jim...The ECM does start in open loop, but it monitors the sensors and determines when to go closed loop based on the sensor output. If the ECM goes closed loop before the sensor is ready, then O2 codes may get set.

 

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My 07 heritage, stock, (well, mufflers) runs 284 rear and 264 front on a 75 degree day.&nbsp\\; Temp taken about 1.5 inches away from the spark plug.&nbsp\\;

 

It has been a while, but I seem to recall while using a high-quality IR meter aimed at the base of the sparkplugs that I would consistently get a 40°F delta between cylinders. Hmm.

Something to consider, folks. On my 07 I measured 5VDC (going from nearly year-old memory) on the ECU-side of the disconnected O2 sensor leads. The O2 sensor, after probably less than a minute of running from cold, will produce a DC voltage proportionate to the amount of free oxygen in its environment. The voltage dividing circuit on the output of the sensor will skew the output as expected, but the result will not be as linear as the original over the sensor range.

What I mean by that is that the voltage swings will be dampened by the divider. Looking at it from the other direction, the ECU will be making wilder changes than the tamer feedback it is receiving. I wonder if this might tend to confuse the ECU somewhat. I know I would find the situation puzzling if it were my task. Hell, I would probably throw an error code to get the attention of whomever it may concern...

At any rate, my point about the supplied voltage source on the disconnected leads makes me have to ask the question: Has anybody considered what effect this resistor network has on the ECU-end of the wires? I believe I recall reading that one should not attempt to measure the resistance of an O2 sensor, but I would imagine it would yield a high figure (depending maybe on the polarity of the instrument leads?). Assuming for the moment it would effectively be infinite resistance it would have little-to-no effect on the source-side of the ECU sensing circuit. I wonder what effect putting 30K ohms across the sensing leads has on the ECU circuit? By way of comparison, I know (or at least seem to recall) that my PC-III eliminators measure right at one megohm resistance.

The ECU sensing circuit is probably not merely acting as a volt-meter measuring the output of the sensor directly. A supply of voltage is not needed for that task. It seems to me that what is happening here is the ECU is measuring how much the 5VDC is biased by the output from the sensor. I wonder what effect that 30K ohms (as seen by the ECU) has on the whole picture...

Just some food for thought for the engineering-minded here.