Closed loop...Open loop...going crazy?!!! Need help please

[lcopas]

First I turned OFF closed loop ... then I tuned my maps ... got my low speed fuel map near perfect and I have the high spped maps looking good too.... no real big discrepencies anywhere on the map ...

I am using a PLX Devices wide band O2 setup ...

Well .. after getting this done ... I smoothed the maps as instructed ... to make sure there were no sharp peaks or valleys ...

So ... then I turned the close loop ON ... so the car will run in closed loop under normal driving conditions....

And then all hell busted loose ... all of a sudden my maps are not even close anymore ... there are large lean areas ..and rich areas that were previously working fine under open loop ....

I cannot figure out why my setup is doing this ... with out making any changes to the maps ... if I turn closed loop OFF .. the car runs fine ... the maps look good ... then turn closed loop ON ... the same maps go to shit ....


PLEASE HELP>>>> this is driving me crazy ...
Thanks in advance ....

[AndyE]

Silly question, but did you switch back to the stock narrow-band O2 sensor when you reconfigured for closed loop?

[lcopas]

I was under the impression that I could run this particular wide band O2 in closed loop ...

It is a PLX Devices O2 ....

Am I wrong in this assumption ?

If so, it would solve my mystery .... because I didn't take the wide band O2 out ...

[AndyE]

I can't speak for what your WB O2 can and can't do...some WB O2 meters claim to support a "narrow band emulation" mode that will mimic the voltage behavior of a standard narrow band O2 meter. If you're simply changing your ROM from open loop to closed loop and not changing anything else, you're guaranteed to fail, because the voltage behavior of a WB O2 meter is much different than what the ECU expects for closed loop operation. At the very least, you would have to somehow manually configure the WB O2 interface box to behave like a narrow band O2 meter.

In pursuit of solving your problem, the first thing I'd try is to hook up your stock O2 meter again.

-Andy

[lcopas]

thanks Andy... I appreciate the advice.... I'll try it and let you know what happens ...
thanks again

[Spunkster]

You must switch from the wideband output to the narrowband output to the ecu from the PLX.

[lcopas]

Ok ... I switched the output on the PLX box from the wide to the narrow band output...

I put a toggle switch on the PLX box, so I can switch from wide to narrow band output.

But my car still goes grazy when I put the ECU in closed loop ... This is driving me nuts ....

Do I have to do anything with the Lambda conversion tables ?

I know when I hooked up the PLX O2 ... I was instructed to go to the Lambda tables and make an adjustment.

0v = 10 A/F and 5v = 20 A/F
Here is the link to the PLX deviced setup instructions.

http://www.plxdevices.com/PLXApp002.htm

My question is... when I put the car back in closed loop ... am I supposed to go back and readjust the Lambda conversion tables ?

Thanks,
Lou

[AndyE]

The Lambda conversion tables have nothing to do with the operation of the ECU. They aren't uploaded or transferred to the ECU in any way. They're simply used by Hondalogger/ROM Editor to convert the WB O2 voltage into a Lambda value. The purpose of this Lambda value is to allow you (as the tuner) to make decisions on whether to add or remove fuel from the fuel tables at a specific RPM/MAP combination.

So in short, no...the Lambda tables have nothing to do with the proper closed-loop operation of your ECU.

[lcopas]

Well .... I guess I just can't run the car in closed loop with the PLX devices O2 sensor ...

The car runs pretty good in open loop ... but it totaly goes berserk when I switch the closed loop .... and use the narrow band output ....

I guess I could rip the whole thing out of the car ... and see what it does then ....


Confused .... I understand Matt and Hondata has one of the O2 setups on his car and hasn't had any trouble ....


hmmmmmmmmmmm