how-to: Log AFR from the LC-1 w/o a serial cable
May 19, 2008, 04:53 PM
#76
Account Disabled
iTrader: (3)
Join Date: Apr 2006
Location: USA
Posts: 1,029
Likes: 0
Received 0 Likes
on
0 Posts
Yeah I really LOVE feeding the 0-5v wideband signal into my stock DSM front O2! That is one of the reasons the car drives so amazing considering it has the power to go 130+ in the quarter. It just starts up, idles, and cruises with authority (and returns amazing fuel economy).
May 19, 2008, 05:06 PM
#77
Yeah I really LOVE feeding the 0-5v wideband signal into my stock DSM front O2! That is one of the reasons the car drives so amazing considering it has the power to go 130+ in the quarter. It just starts up, idles, and cruises with authority (and returns amazing fuel economy).
May 19, 2008, 08:30 PM
#78
After reading dan l's post, I understand what you want. This would be pretty easy to do and would be pretty cool. So basically, the need here is to convert the 0-5 V analog linear WB signal into a narrowband signal. I'm not sure I'd trust my LC-1 to be reliable enough for this, but if someone wants to do it, I could write the code for this. I think it would actually be kinda fun too.
The stock O2 sensor would have to stay in the O2 housing until I can figure out how to simulate the heater signal or manipulate the readiness codes.
Also, for optimum idle quality, the WB sensor would need to be as close to the turbo as you could stand. This reduces the time delay between when exhaust fumes leave the engine and when the sensor detects it. The closer to the turbo, the faster the variations in AFR can be corrected. This kinda matters at idle because the exhaust gases are moving pretty slowly.
The stock O2 sensor would have to stay in the O2 housing until I can figure out how to simulate the heater signal or manipulate the readiness codes.
Also, for optimum idle quality, the WB sensor would need to be as close to the turbo as you could stand. This reduces the time delay between when exhaust fumes leave the engine and when the sensor detects it. The closer to the turbo, the faster the variations in AFR can be corrected. This kinda matters at idle because the exhaust gases are moving pretty slowly.
May 19, 2008, 08:51 PM
#79
Evolved Member
iTrader: (17)
Join Date: Nov 2005
Location: NNJ
Posts: 2,544
Likes: 0
Received 0 Likes
on
0 Posts
Cuz I'd rather wait until one of these disam geniuses figures out how to mod the front O2 code so we can use the 0-5v linear analog output to control the closed loop operation with an ECUFlash adjustable switching point. Just like the 1G DSM guys have already done. This way I'm using this input for 2 things while also freeing up another ADC input. Win win. The zeitronix .15-3.27 volt NON-linear analog output isn't all that accurate and I don't feel confident using it but the 0-5v linear output I would definitely use. Unfortunately, thats the same wire that I am currently using for my narrowband simulated output set to 15.5AFR for closed loop. If I wasn't already using it, I'd have that permanently hooked up.
Anther question - why do you want to use the wideband for closed loop? Does it work better then the stock front 02 sensor at this, or are you just trying to free up some ADC inputs?
May 20, 2008, 01:08 PM
#81
Account Disabled
iTrader: (3)
Join Date: Apr 2006
Location: USA
Posts: 1,029
Likes: 0
Received 0 Likes
on
0 Posts
After reading dan l's post, I understand what you want. This would be pretty easy to do and would be pretty cool. So basically, the need here is to convert the 0-5 V analog linear WB signal into a narrowband signal. I'm not sure I'd trust my LC-1 to be reliable enough for this, but if someone wants to do it, I could write the code for this. I think it would actually be kinda fun too.
The stock O2 sensor would have to stay in the O2 housing until I can figure out how to simulate the heater signal or manipulate the readiness codes.
Also, for optimum idle quality, the WB sensor would need to be as close to the turbo as you could stand. This reduces the time delay between when exhaust fumes leave the engine and when the sensor detects it. The closer to the turbo, the faster the variations in AFR can be corrected. This kinda matters at idle because the exhaust gases are moving pretty slowly.
The stock O2 sensor would have to stay in the O2 housing until I can figure out how to simulate the heater signal or manipulate the readiness codes.
Also, for optimum idle quality, the WB sensor would need to be as close to the turbo as you could stand. This reduces the time delay between when exhaust fumes leave the engine and when the sensor detects it. The closer to the turbo, the faster the variations in AFR can be corrected. This kinda matters at idle because the exhaust gases are moving pretty slowly.
You wouldn't be changing the 0-5 volts into narrowband. You would actually sent the 0-5 volts straight to the ecu and tell the ecu to switch around the 2.5v mark (14.7:1AFR). I have the code of how they did it on the stock DSM ecu if you want to PM me I can send it to you.
Also I don't think the AFR delay will be a big deal. I have my wideband sensor in my downpipe at the firewall on my DSM and the car runs fine with it there.
The O2 heater is no big deal. Thats something that will be figured out some day, in the meantime a resistor is the fix.
May 20, 2008, 01:21 PM
#82
Yep, I was thinking what you just wrote. I was thinking that I would just use a 5 element table to create a steep narrowband slope with the corners knocked off. Outside the range, the translated NB value would be 1 (or something close to 1) for rich side and 0 (or something really small) for lean side. I'll have to look again at the OBD-II stuff to see what types of error checks are done. If you want to PM the code, that would be a good way for me to get started.
May 20, 2008, 04:29 PM
#83
You only need 3 elements, if not just the one switching point element. The switching point (I'll use 2.55v as an example since that is what equals 14.7AFR with the zeitronix but you'd want this adjustable for different analog inputs and for people trying to richen or lean out their closed loop tuning), below the switching point, and above the switching point.
12
Basically, you're telling the ECU "below 2.5volts....remove fuel, above 2.5volts...add fuel." Thats it. It will never be exactly at the 2.5 volts since its constantly changing so there is no need to tell it to do nothing at the 'exact' switching point I'd imagine?
12
Basically, you're telling the ECU "below 2.5volts....remove fuel, above 2.5volts...add fuel." Thats it. It will never be exactly at the 2.5 volts since its constantly changing so there is no need to tell it to do nothing at the 'exact' switching point I'd imagine?
May 20, 2008, 04:54 PM
#84
If the OBD-II stuff is happy with a step function, then I would definitely do it that way. It would be super easy to implement. Could be as simple as 10-15 lines of code. I always like to keep the OBD-II stuff happy because many people have to pass emissions tests.
May 21, 2008, 06:37 AM
#86
Basically, you're telling the ECU "below 2.5volts....remove fuel, above 2.5volts...add fuel." Thats it. It will never be exactly at the 2.5 volts since its constantly changing so there is no need to tell it to do nothing at the 'exact' switching point I'd imagine?
Jun 3, 2008, 01:32 PM
#89
Evolving Member
iTrader: (11)
Join Date: Apr 2004
Location: D.C.
Posts: 197
Likes: 0
Received 0 Likes
on
0 Posts
Just wanted to give props to MrFred again for a perfect write up. I was having all kinds of issues getting my LC-1 to work until I hard wired it up and used MrFreds and Tephra's patches. Now it works perfectly, well with one exception.
Has anyone noticed a sort of feedback noise through the stereo after performing this mod. I am currently experiencing this and think that it maybe a grounding issue.
Has anyone noticed a sort of feedback noise through the stereo after performing this mod. I am currently experiencing this and think that it maybe a grounding issue.