Autotune with a WB - Heater circuit problems

[BottleFed70]

OK, so it turns out that mounting the wideband O2 in the exhaust H-pipe (crossover pipe... whatever) may not have been the best idea. It allows me to sample O2 data from both banks... BUT, it doesn't appear to be warm enough..especially at idle.

So what happens is that the controller (LC1) periodically fires up the heater circuit. Unfortunately, during these 20 seconds or so, it supplies 0V to the the megasquirt fooling the MS into thinking my AFR is 10:1

I'm worried that autotune will see this and get very confused.

Can anyone think of a way to get around this? It shouldn't be a problem once the car is tuned and I set the EGO authority to something like 10%... but I'm sure it'll cause havoc with autotune.

It would be nice to somehow tell autotune to "pause" if the AFR goes below 10.5:1 or something similar to that.

[efahl]

It would be nice to somehow tell autotune to "pause" if the AFR goes below 10.5:1 or something similar to that.

Hack up your custom.ini by adding this new variable and then change the proper table definition in the auto-tune section...

Code: Select all

[Datalog]
   trimmedCorrection = { afr < 10.5 ? 100 : egoCorrection }

[AutoTune]
   ...
   corrector = trimmedCorrection
   ...

Eric

[blk 02]

HEy BottleFed70,

Do you think that the cross over is an ideal place for a WB02? I was thinking that this position is not the best, because the only time there is exhaust flow through a cross over when there is a pressure difference between the two banks. Wouldn't it be better to sample only side then to sample in the crossover? Moving the sensor to one side would also help with your lack of heat problem too.

Graham

[BottleFed70]

HEy BottleFed70,

Do you think that the cross over is an ideal place for a WB02? I was thinking that this position is not the best, because the only time there is exhaust flow through a cross over when there is a pressure difference between the two banks. Wouldn't it be better to sample only side then to sample in the crossover? Moving the sensor to one side would also help with your lack of heat problem too.

Graham

To be honest, I'm not too sure.

I havn't had a chance to get the car out on the road much, so I can't tell you how it's working so far. I can say that low RPM (less than 3500) doesn't seem to be a problem.

But I've been thinking the same thing myself. I may end up getting a new O2 bung welded in.

[BottleFed70]

It would be nice to somehow tell autotune to "pause" if the AFR goes below 10.5:1 or something similar to that.

Hack up your custom.ini by adding this new variable and then change the proper table definition in the auto-tune section...

Code: Select all

[Datalog]
   trimmedCorrection = { afr < 10.5 ? 100 : egoCorrection }

[AutoTune]
   ...
   corrector = trimmedCorrection
   ...

Eric

That was quick! Thanks Eric! I'll give it a try as soon as my new ignition modul arrives in the mail.

[midnightblue]

I had a similar issue with LC-1 dropping it's readout down to 10.0 and then recovering after 10 seconds or so.

Played havoc with my ego corrections, and Autotune hated it!

Turned out, it wasn't the heater control on the LC-1, it was a momentary power supply dropout to the LC-1 caused by a relay on the car. The LC-1 thinks it's just been switched on, then goes into it's initial startup/warmup cycle, and then comes back online after a few seconds.

Hope that helps, Matt.

[BottleFed70]

I had a similar issue with LC-1 dropping it's readout down to 10.0 and then recovering after 10 seconds or so.

Played havoc with my ego corrections, and Autotune hated it!

Turned out, it wasn't the heater control on the LC-1, it was a momentary power supply dropout to the LC-1 caused by a relay on the car. The LC-1 thinks it's just been switched on, then goes into it's initial startup/warmup cycle, and then comes back online after a few seconds.

Hope that helps, Matt.

Thanks Mat,

Power is connected to the fuel pump relay..so I don't think this is the problem. But I'll check it out just in case. Could be a bad ground as well I suppose.

[ETECH]

Hi,

Just a tip:
With the advanced settings of the LC-1 you can program what voltage it outputs during warmup or error. You can program that to be some safe value.

Regards

[midnightblue]

Hi BottleFed70,

I also have mine connected to the fuel pump relay for power, following the OEM wiring. MS was having tach signal and RMP issues at the time, when it thinks it has 0 RPM it turns the fuel pump relay off immediately, until it reads an RMP again. Even a brief interrruption of power to the LC-1 made it begin the startup/warmup process again. That was the root cause in my case, think I've got the tach signal sorted now, so no further LC-1 resets.

Hi ETECH,

That's very useful, guess I need to read the manual more thoroughly in future. The LC-1 is a great product.

Thanks, Matt.

[BottleFed70]

Hi BottleFed70,

I also have mine connected to the fuel pump relay for power, following the OEM wiring. MS was having tach signal and RMP issues at the time, when it thinks it has 0 RPM it turns the fuel pump relay off immediately, until it reads an RMP again. Even a brief interrruption of power to the LC-1 made it begin the startup/warmup process again. That was the root cause in my case, think I've got the tach signal sorted now, so no further LC-1 resets.
Thanks, Matt.

OK, that makes alot of sence! I don't appear to be having any RPM signal problems, but I'll defiantely check that!