Ls2 Swap in Boxster 180 deg Header, LtFt question ,WB Stoich won't change

[Frank19]

Hi, I have a LS2 with an E40 PCM in a Porsche Boxster. I built a 180 deg Exhaust header. I had problems with the O2 Sensors getting mixes input and and signaling lean and rich until I changed the injector selection, which seemd to fix ist.
Now i am loging the engine and also have a Innovative wideband hooked up. I have several questions.

1)I calibrated the wideband and the external instrument shows 15,2 to 15,6. I got the Wideband into the log. I will plot lamba but it wont plot Stoich. it remains at 14.7. Why is that?

2) Before the change in inlector selection the STFT seperated. one bank was rich the other lean. Now it seems to work, but the LTFT now shows one bank in plus the other in minus. Is that a problem and how can it be fixed.

3) when I raise the RPM the Enginedsoes not stay constant it waves up and down. I heard that could be a rich running engine. Is that correct. Would lambda show me that?

4) i tried to plot the closed loop second sensors (after CAT). When I select them in the charts, B2S2 and B2S2 plot exactly the same value. Also the value should be more level then the pre CAT sensors which it is not. Am I really plotting the correct sensors?


I would be nice if somone could help me. I am new to this.

Thanks, Frank

[5FDP]

Usually if one bank is full rich and the other is full lean that means the o2 sensors are installed in the wrong banks (the harness is anyway).

I can't see the logs to see what it going on right now.

[Frank19]

I attached the log. i dont|t think the O2 sensors are on the wrong bank. As i mentioned, after correcting the Injector Bank selection for the 180 deg exhaust, the sensors and the short term fuel trim seem to work correctly. Unless someone else can see somthing I can't. The long term fuel trim is strange.

[eXo3901]

1 - No idea. Just use the lambda channel if it works? Which bank is it in?
2 - Did you clear the LTFT and it still goes opposite?
3 - Not really seeing wavy rpm in the log that isn't caused by a moving accel pedal. The spots where it looks like you used the scanner to command a higher RPM does look to be slightly following the O2 swings.
4 - The rear O2s look to be following the front O2s just fine. Bank 1 seems to be a little off compared to Bank 2. Not sure if that is related to your injector settings change or scanner polling rate though.

Except for the exhaust, everything with the motor and the parts attached to it are stock from the donor car?

[Alvin]

1. I don't know but it is outputting EQ ratio which is really what you should be using. The Innovate SP Stoich AFR just looks like what AFR the wideband is currently set for. This depends on what gas your using. Its best just to use EQ or lambda. You can remove that channel/ignore it. That pid basically just looks like a way to check to make sure your wideband is setup for same gas as you are using.

2. I can't think of why you should change injector selection. Unless the firing order changed.. Or literally some even cylinders are being tied into odd cylinders for exhaust.

3. This looks to be o2 sensor/feedback issues to me.

4. You are plotting them but I doubt you'd be able to use it for anything.

[Frank19]

Yes everything ist stock, I had build my on intake pipe and the throttlebody is at about 90deg to the original intake flange and the MAF sensor about 60 deg to the throttlebody
The rpm swinging is not from my foot on the pedal. you can also hear it. it is only at higher RPM.
I did not clear the LTFT only that I hade the PCM off power for some time. how do I clear it?
The WB O2 Sesnor is on Bank 2 (passenger side)

[Frank19]

1. I don't know but it is outputting EQ ratio which is really what you should be using. The Innovate SP Stoich AFR just looks like what AFR the wideband is currently set for. This depends on what gas your using. Its best just to use EQ or lambda. You can remove that channel/ignore it. That pid basically just looks like a way to check to make sure your wideband is setup for same gas as you are using.

2. I can't think of why you should change injector selection. Unless the firing order changed.. Or literally some even cylinders are being tied into odd cylinders for exhaust.

3. This looks to be o2 sensor/feedback issues to me.

4. You are plotting them but I doubt you'd be able to use it for anything.

I had to change the Injector selection, because on the 180 deg headers the middle 2 cylinder outputs change side and feed into the oposite exhaust and confuse the O2 sensors. when changeing the incector selection these now are feeding to the correct o2 sensors.

[Alvin]

I'm not sure that switching the cylinder/which o2 is responsible for trimming it will work. IT does work in earlier ECM's like 411 swaps, LT1 SBC2 swaps, etc. Just keep that in mind.

At this point I think your issue can be solved by reducing ECM 12480 Proprotional O2 and making the integral delay longer. ECM 12470

[Frank19]

I'm not sure that switching the cylinder/which o2 is responsible for trimming it will work. IT does work in earlier ECM's like 411 swaps, LT1 SBC2 swaps, etc. Just keep that in mind.

At this point I think your issue can be solved by reducing ECM 12480 Proprotional O2 and making the integral delay longer. ECM 12470

by what factor would I have to reduce and relay it.

[Alvin]

You'll just have to experiment. It's one of those things that are done more by feel than any sort of math.