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Old 11-16-2012, 02:43 PM   #226
fred flintstone
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Very nice discussion here Roger, thanks much for your insight and experience.
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Old 11-16-2012, 07:53 PM   #227
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I have been out of town for the past two days so I am catching up. This is a great discussion.

If you set the closed loop to 13.8 and enrichen by 6%, aren't you double dipping? Why not just set the AFR to 13.5 if that is where you want to be?

Now I feel the need for an AFR guage for the PCIII.

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Old 11-16-2012, 09:09 PM   #228
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Originally Posted by Mr. Canoehead View Post
I have been out of town for the past two days so I am catching up. This is a great discussion.

If you set the closed loop to 13.8 and enrichen by 6%, aren't you double dipping? Why not just set the AFR to 13.5 if that is where you want to be?

Now I feel the need for an AFR guage for the PCIII.

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You've asked a good question. The simple answer is that it is not a double enrichment. Now I'll try an explanation.

When you're running a stock motorcycle with a stock (14.7:1) narrowband O2 sensor, the Motronic starts it's fueling calculation by reading RPM and TPS and looking up an injection-pulse time. That gets adjusted to compensate for the things its sensors measure (e.g. Air Temp) and at the end of that chain of calculations, out pops a pulse of, say 2.5 mIlliseconds. Now assuming that TPS is steady and the speeds are in the cruising range, that 2.5 mS is supposed to be just the right amount of fuel to yield an afr of 14.7:1. If that is all correct, it matches what the O2 sensor is looking for. (It's more complicated than that but the idea is correct.)

Now let's say you want a 6% richer closed loop. So you program the Wideband O2 sensor to 13.8. But the pulse coming out of the Motronic is, at the start, only 2.5 mS and is only enough fuel for an afr of 14.7:1. You have two choices: 1) Wait for Adaptation to "learn" the size of the error and lengthen the pulse; or 2) Use the PC III to add 0.15 mS (6%) so the starting pulse becomes 2.65 mS and is rich enough to hit 13.8.

Either case 1) or 2) will get you there but choosing case 2) is better since the Motronic has less work to do to converge on the right Adaptation Value. Also it is likely in the Motronic that the Adaptation Values table is coarser than either the Motronic Fuel Table or the PC III add-on table. The bottom line is the less adaptation, the better.

In my LC-1 implementation I don't have an add-on fuel table like the PC III. At first I let adaptation take care of things. But it takes a while (verified by measurement). Next I used a BoosterPlug to add 6%, but if the Motronic does anything besides adding fuel when make the air look colder, like changing spark advance, I wouldn't know it. Also, the BP adds a fixed 6% and I wanted to be able to adjust the Open Loop enrichment. Bottom line, I added a variable fuel pressure regulator.

The whole idea is get the Open Loop fueling as close to your target AFR in the cruising range as you can so that closed loop doesn't have to create large Adaptation Values.

One last point: the Motronic fuel table, in the cruise area, is 14.7 for gasoline. When you run ethanol (E10) you need 4% more fuel for the same afr (more precisely, for the same Lambda value). So if you want lambda 6% richer and run E10, you need to add 10% to the PC III add-on table to end up with a minimum Adaptation.

Long answer, but those are the reasons.

RB
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Old 11-16-2012, 09:17 PM   #229
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Regarding adding an AFR gauge, the gauge can give you an idea what's happening (I have a gauge), but nothing beats a real-time plot. Stuff happens so fast you never see it on the gauge. I learned this the hard way. Much of what I've learned came after I started real-time logging.
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Old 11-17-2012, 08:05 AM   #230
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It would be interesting if somebody had access to an exhaust gas analyzer to see what actually was going on. It would act as a secondary check on what was happening.

14.7 to 1 or even greater AFM are not really an issue when an engine is in cruise mode, with no real load on it, its only when you are asking for power and then that mixture becomes too lean, and you get pinging/surging etc.

In general terms the computer only really relearns everything if you cut the power off and force it to go back to its base data. Then over several miles if will relearn the proper settings, store them and then reuse them at the next startup and then again adapts to any changes detected by the various sensors.

The issue with the lean AFM is when the system is in closed loop, then no matter what, the stock setting is going to be the 14.7 to 1 when the engine is at operating temperature. This is the area that the engine has to meet its EPA guidelines. There is no real issue when an engine is in open loop ( everything before & after closed loop ) as it operates richer than 14.7 to 1.

If you look at Harleys different stage downloads for the computer it still keeps the AFM at 14.7 to 1, but it does raise the rev limiter so that the engine can rev higher which with the added fuel, breathers, cams etc the engine will develop more hp & torque but at the upper rev range.

With adding a flat 6 % its really too bad there isn't a simple cost effective solution like an XIED for a BMW.
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Old 11-17-2012, 11:51 AM   #231
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With adding a flat 6 % its really too bad there isn't a simple cost effective solution like an ZIED for a BMW.
Isn't that exactly what the booster plug (and it's competition) do? PCIII's are pretty cheap if you buy them used.

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Old 11-17-2012, 12:03 PM   #232
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Isn't that exactly what the booster plug (and it's competition) do? PCIII's are pretty cheap if you buy them used.

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The problem is that the BoosterPlug drops the temperature to a point that 6% is added but in order to maintain that gain in Closed Loop you need to offset Lambda as well.

Steve Mullen at www.Nightrider.com has the Xieds for Harleys and he's told me that he would be willing to develop one for BMWs if there was enough demand. The good thing about Steve is that he really understands the characteristics of the stock Narrowband sensors. The problem is that the O2 input works differently on the Delphi-based Harley ECU than on the Motronic so he would have to do some development. If enough people petitioned him he might build an IED device for the Oilhead.

Can you point me to a cheap PC III USB?

Also, I updated the PC III block diagram here: Wideband O2 Thread

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Old 11-17-2012, 12:24 PM   #233
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Originally Posted by roger 04 rt View Post
The problem is that the BoosterPlug drops the temperature to a point that 6% is added but in order to maintain that gain in Closed Loop you need to offset Lambda as well.

Steve Mullen at www.Nightrider.com has the Xieds for Harleys and he's told me that he would be willing to develop one for BMWs if there was enough demand. The good thing about Steve is that he really understands the characteristics of the stock Narrowband sensors. The problem is that the O2 input works differently on the Delphi-based Harley ECU than on the Motronic so he would have to do some development. If enough people petitioned him he might build an IED device for the Oilhead.

Can you point me to a cheap PC III USB?

Also, I updated the PC III block diagram here: Wideband O2 Thread
I can't imagine that there is enough demand for 1150 oilhead parts that developing anything new is worthwhile. These bikes have been out of production for 7 years.

As far as finding a used PCIII, watch the FM here or ebay. I got mine here.



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Old 11-17-2012, 04:20 PM   #234
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Yes that's my understanding of the Booster plug or any air temp sensor for that matter.

If anybody has a spare air box sensor ( I have and I tried this ) and an ohm meter. Put the sensor in room air, into the freezer/fridge and warm it up with your hand. You'll see that the resistance changes depending on the temperature. It operates in a fairly narrow range. This is not really an accurate measurement because I think this is actually a variable condenser of some type. The ohm meter will register the changes but it is not accurate. This sensor responds in exactly the same as the stock Harley plug does with the Delphi ignition system. My view is that the air temp sensor works very much like the old automatic choke set up on carbed engines. Once the engine is up to operating temp this sensor adds very little info to the computer. The 02 sensor takes over.

I guess if you look at this sensor in the similar fashion to a Bing carb, you have a choke/enrichment circuit, idle/pilot circuit, needle & main jet. At each stage each part adds to the whole fuel mixture, but once the needle is coming out of the main jet & then the needle is fully out of the main jet the first two stages impact on the total mixture is minimal. For the sake of this example the 02 sensor equates to the same range that the needle jet is affecting the mixture.

When you go to EFI then all the various sensors are sending a small voltage to the ECM which then calculates fuel and/or timing. Something had to replace the mechanical points and the carbs so that's what the various sensors are actually doing.
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Old 11-17-2012, 05:02 PM   #235
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Can you point me to a cheap PC III USB?
Sent you a link.


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Old 11-18-2012, 05:01 PM   #236
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Quick question for Mr Canoehead and Roger:

Have either of you run the timing advance trick Poolside wrote up, since going wideband? Looks like my AFR gauge may not ship for a while and I wanted to try something before all riding shuts down here completely for 4 months or so. This is the trick:

http://advrider.com/forums/showthrea...timing+advance
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Old 11-18-2012, 05:41 PM   #237
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Hmmm.... well, I know that my bike pings on regular fuel, so I don't think I want to advance the static timing any more than it already is. It doesn't ping on premium so I don't want to retard the static timing, either. I might try

Also, take out the timing hole plug at your own risk! I took that damn thing out once when adjusting the valves and it is a PITA to reinstall because you can't reach it with your fingers. I finally got it back in place only to have it fall out on the next ride (so I guess it wasn't seated). I had to cover the hole with duct tape for a while until I got a replacement and I was a lot more careful to insert it properly. Use a seal driver if you have one. I later realized that I could use the cam marks when setting the valves, so removing that cover wasn't necessary.

I'm hoping Roger gets the PCIII I sent him the link for, I'm looking forward to his feedback on the fuelling tables. I think I'm going to get a new sensor for the PCIII for next season. Does anyone know if you can split the signal off one O2 sensor - I'm thinking about running the LC-1 off the same sensor? It might just be easier to add another bung but there isn't a lot of space down there.

What is the delay on the gauge? Dynojet won't ship to Canada (don't get me started on the crooks at Parts Canada), so getting parts here is always an issue.
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Old 11-18-2012, 08:29 PM   #238
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I'm with Mr. canoe head. I would set the timing to spec. Richening the mixture produces a faster flame speed and therefore to some degree acts as an advance. I should check my timing at some point.

I don't know if one sensor could drive two instruments. There is a pump circuit that each would be trying to control. I'm wrestling with the same issue, do I add a second bung.

In my experience the gauge is only of modest value since things happen much faster than a gauge can register. It gives you a coarse idea what's happening.

I'm still trying different coding plugs but am going over the same ground a second time, checking the results.

Contacted the PC III seller, discussing price. I may have to buy a new one and then resell.
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Old 11-18-2012, 09:18 PM   #239
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Originally Posted by cycleman2 View Post
Yes that's my understanding of the Booster plug or any air temp sensor for that matter.

If anybody has a spare air box sensor ( I have and I tried this ) and an ohm meter. Put the sensor in room air, into the freezer/fridge and warm it up with your hand. You'll see that the resistance changes depending on the temperature. It operates in a fairly narrow range. This is not really an accurate measurement because I think this is actually a variable condenser of some type. The ohm meter will register the changes but it is not accurate.
I have no experience with the temperature sensors on our BMWs but, I would suspect they are NTC thermistors which are relatively accurate temperature sensors. However, measuring the resistance change with temperature is difficult because of the self heat phenomena that takes place with a typical VOM. Thermistors have accuracies to 1 C., some even to 0.1 C.

Using the Steinhart-Hart equation, temperature is calculated using the change in resistance reported by the thermistor.
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Old 11-18-2012, 09:21 PM   #240
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Originally Posted by cycleman2 View Post
Yes that's my understanding of the Booster plug or any air temp sensor for that matter.

If anybody has a spare air box sensor ( I have and I tried this ) and an ohm meter. Put the sensor in room air, into the freezer/fridge and warm it up with your hand. You'll see that the resistance changes depending on the temperature. It operates in a fairly narrow range. This is not really an accurate measurement because I think this is actually a variable condenser of some type. The ohm meter will register the changes but it is not accurate. This sensor responds in exactly the same as the stock Harley plug does with the Delphi ignition system. My view is that the air temp sensor works very much like the old automatic choke set up on carbed engines. Once the engine is up to operating temp this sensor adds very little info to the computer. The 02 sensor takes over.

I guess if you look at this sensor in the similar fashion to a Bing carb, you have a choke/enrichment circuit, idle/pilot circuit, needle & main jet. At each stage each part adds to the whole fuel mixture, but once the needle is coming out of the main jet & then the needle is fully out of the main jet the first two stages impact on the total mixture is minimal. For the sake of this example the 02 sensor equates to the same range that the needle jet is affecting the mixture.

When you go to EFI then all the various sensors are sending a small voltage to the ECM which then calculates fuel and/or timing. Something had to replace the mechanical points and the carbs so that's what the various sensors are actually doing.

???

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