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Discussion Starter #1
Hi Everyone

I may have found a possible way to add autotune to the PV3 on the monkey and the grom, but I'm not sure if anyone here has tried this already. For reference, I have an Aus Monkey 125.

One of the variables in the learning section of the PV3 tune is the "O2 Transition Voltage (Target AFR) Threshold". This is the narrowband voltage that the ecu targets when adjusting trims in closed loop. The stock value for an Aus Monkey is 0.605v, and I have set mine to 0.7v which gives a similar outcome to using an EFIE.

The min/max values that can be inputted for this variable are 0V and 4.98V, respectively. My idea is that you could wire up the 5V output from a wideband gauge to the narrowband wire and set the target to 1.5V which gives an AFR of 13 (for gauges which output [email protected] and [email protected]).

If this works, the benefits are getting an "Autotune" of sorts and also a much cheaper wideband set up. The dynojet WBCX is 350USD, vs say a Spartan 2 for 125USD. You'd have to flash the closest premade map to your setup, set the target voltage to whatever AFR you want, and then the ecu would trim to target that.

The PV3 software also allows you to alter the closed loop rev cutoff, so if this worked, theres no reason why you couldn't have it trim all the way to the limiter.

Let me know in the comments what you think. If anyone out there has a wideband gauge with 5V output and a PV3, I'd love to know if this works. Otherwise, I'll just have to get a Spartan 2 and test it myself in the near future.
 

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With regards to open loop, won’t it just run off the loaded map without any assistance from the O2 sensor? So if the map isn’t right you’ll still have problems in open loop?

Would it not be better to data log and adjust the map so it is better throughout the entire RPM range? The PV3 has the function to data log and map can be adjusted with the included software, is that correct?
 

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Sorry just saw that part about altering the closed loop, so you can keep it in closed loop the entire time to use the O2 sensor?
 

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Discussion Starter #4
Sorry just saw that part about altering the closed loop, so you can keep it in closed loop the entire time to use the O2 sensor?
Yeah that's right. You can set it up so there isn't an open loop at the top end.

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Discussion Starter #5
Would it not be better to data log and adjust the map so it is better throughout the entire RPM range? The PV3 has the function to data log and map can be adjusted with the included software, is that correct?
The data logging would be fine to bring the map closer to the right amount (to reduce trims). The problem is you either have to use the stock narrowband (which is only accurate for a small range around 14.7 AFR), or you have to turn off learning entirely.

I'm hoping that the method I wrote works, so that you can retain learning/trimming and still target a richer afr



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The data logging would be fine to bring the map closer to the right amount (to reduce trims). The problem is you either have to use the stock narrowband (which is only accurate for a small range around 14.7 AFR), or you have to turn off learning entirely.

I'm hoping that the method I wrote works, so that you can retain learning/trimming and still target a richer afr



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Just with a pv3 flash from a canned map that gave +450 rpm's, and a cheap pipe costing ~ $90 or so, +2 teeth on rear sprocket, opened airbox from the radiator hose over the intake mod, removal of airbox with Uni filter on the other end of the radiator hose, oil spinner removed for that Kitaco oil filter... and the speed screen! I think that's it and I've since hit 72.79 mph on my gps device. Rounded up that 73 mph on a stock engine. Closed loop ops never been a concern for me and I'm wondering what's to gain?
 

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Discussion Starter #7
Closed loop ops never been a concern for me and I'm wondering what's to gain?
Well it's not really an issue for a stock motor. This is more for setting up mods like a big bore, cam or larger throttle body.

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Can you reverse your wideband output so that 0v = 20 AFR and 5v = 10 AFR? If so, then your method would work....assuming you're OK with a fixed closed loop target of "x_AFR". The issue is that the narrowband logic treats higher voltages (above .605v) as a rich condition, and lower voltages (below .605v) as a lean condition. Your wideband, and most wideband controllers indicate leaner AFR's with higher voltages.........while the Honda control logic is going to treat higher voltages as richer conditions, and vice versa.
 

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Discussion Starter #9
That's a good point. I'll look at the trim adjustment parameter table and see if it allows reverse adjustments. Otherwise I'll have to see if the wideband controller can be adjusted how you said

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I have the Power Vision and Wideband kit. There is a better way to do this.

Retain the narrowband and alter the target voltage to be a little more rich (if you desire).
Adjust your throttle and RPM open/closed loop transition points.
Weld a wideband bung to the exhaust.
Log your data.
Run a TuneLab script (available from Dynojet and available on this forum) to analyze the narrow/wideband data with a target AFR map and adjust your fuel map automatically.
Smooth your altered areas of the fuel map.
???
Profit.

I did a 2 minute log once a day on my ride to work with a reflash every morning for about a week. After 3-4 logs, fueling changes were minimal.

The script is very well thought out - it gives priority to STFT over wideband data leading to less closed loop correction. It also discards wildly rich/lean data (such as decel fuel cut). Lastly, it allows the user to trim portions of the log they deem irrelevant.
 

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Discussion Starter #11
So you can't change the highV=low afr to highV=high AFR in the PV3 software.

It seems like you can achieve this with some of the wideband controllers, but not all. The Spartan 2 I was considering can't do this, but it looks like the innovate lc2 can be programmed to do this. Not as cheap, but still a lot cheaper than dynojets wideband kit.

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Discussion Starter #12
I have the Power Vision and Wideband kit. There is a better way to do this.

Retain the narrowband and alter the target voltage to be a little more rich (if you desire).
Adjust your throttle and RPM open/closed loop transition points.
Weld a wideband bung to the exhaust.
Log your data.
Run a TuneLab script (available from Dynojet and available on this forum) to analyze the narrow/wideband data with a target AFR map and adjust your fuel map automatically.
Smooth your altered areas of the fuel map.
???
Profit.

I did a 2 minute log once a day on my ride to work with a reflash every morning for about a week. After 3-4 logs, fueling changes were minimal.

The script is very well thought out - it gives priority to STFT over wideband data leading to less closed loop correction. It also discards wildly rich/lean data (such as decel fuel cut). Lastly, it allows the user to trim portions of the log they deem irrelevant.
Considering how much more expensive the Dynojet kit is, this doesn't really sound like a better solution to me.

I'm not sure why you would want to retain the stock narrowband if it was possible to have ltft and stft based on wideband data. The narrowband is only really good over a narrow range (~14.2-15.2 AFR).

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So you can't change the highV=low afr to highV=high AFR in the PV3 software.

It seems like you can achieve this with some of the wideband controllers, but not all. The Spartan 2 I was considering can't do this, but it looks like the innovate lc2 can be programmed to do this. Not as cheap, but still a lot cheaper than dynojets wideband kit.

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You can, but mine still seems to settle into 14.7:1 regardless of voltage setting. In a similar manner, my injector duty goes to 0 on decel even with decel fuel cut disabled.

Considering how much more expensive the Dynojet kit is, this doesn't really sound like a better solution to me.

I'm not sure why you would want to retain the stock narrowband if it was possible to have ltft and stft based on wideband data. The narrowband is only really good over a narrow range (~14.2-15.2 AFR).

Sent from my Pixel 2 using Tapatalk
With the way the Grom ECU is setup, having both sensors makes tuning a little more efficient as you can prioritize one over the other if you write a fuel correction script.

The best part of the PV CX is that you're reflashing the OEM ECU and can disconnect the box afterwards. That and the ignition table tuning, of course. There is a LOT of untapped potential with the Power Vision... but on a bike that will likely top out at 25 whp with a good BBK, it's a lot of work for tiny gains.
 

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Discussion Starter #14
You can, but mine still seems to settle into 14.7:1 regardless of voltage setting. In a similar manner, my injector duty goes to 0 on decel even with decel fuel cut disabled.



With the way the Grom ECU is setup, having both sensors makes tuning a little more efficient as you can prioritize one over the other if you write a fuel correction script.

The best part of the PV CX is that you're reflashing the OEM ECU and can disconnect the box afterwards. That and the ignition table tuning, of course. There is a LOT of untapped potential with the Power Vision... but on a bike that will likely top out at 25 whp with a good BBK, it's a lot of work for tiny gains.
If your bike keeps going back to 14.7, then it means your narrowband reading is governing the fuel trims..... That's why I want to replace it.

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My point was that I have modified the voltage target table and it didn't matter - the closed loop target remains 14.7:1. This is contrary to what Dynojet explained to me, therefore I believe the table being modified in the ROM isn't what Dynojet assumes it to be.

This table illustrates what I'm working with:

afrnbb.jpg

Stock transition voltage is 0.605 V. I'm using almost 0.700 V and the results are the same - 14.7:1.

I can't recommend that you try to drive the ECU narrowband input pin without a PCB inline to translate the signal into something usable. By all means, give it a shot if you want... but there are easier ways to tune your bike than coming up with some roundabout way of fooling the ECU.
 
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