I've been looking for a post that covers tuning with a wideband O2 and an AIR system intact. I have had little luck finding how it is being done without removing the pump. After consulting a shop manual I have learned that on my setup, TPI L98 with 165 ecm in an '88 gta, that there are two solenoids in the AIR control valve. These solenoids work in series as far as air system plumbing is concerned. The divert valve is first downstream of the air pump. It either diverts air to atmosphere when de-energized or sends it to the switching valve when energized. The switching valve sends the air to either the catalytic converter when de-energized or the exhaust manifold when energized. The additional air in the system doesn't seem to be a problem when the ecm is in closed loop mode as the air is sent to the catalytic converter or diverted to atmosphere depending on certain conditions. This makes tuning with a wideband O2 non-problematic while in closed loop. However, if tuning in open loop the additional oxygen that will be injected into the exhaust manifold will cause a lean reading from the wideband O2 when the AIR system is configured to send air to the manifold.

Anyone want to correct me so far? Feedback is welcome.

If you want to use your wideband to get accurate data in open loop you should disconnect the switching valve, grey connector at the control valve, while tuning with the wideband and reconnect when finished tuning.

This post is meant to provide information to anyone who may be trying to tune with their AIR system intact.

Feedback is welcome.

 

I beleive you can also just set the minimum enable temp to 151* C (the max value) in the BIN so that it is never "turned on" by the ECM. As I understand it, that should divert all air to atmosphere and not send any into the exhaust. However, I'm using $8D on a 730, so your set up may be entirely different. SOrry I couldn't be of more help.....

 

I went through the 6E arap bin that I am running and there is not a enable or disable based on temp. My reading actually indicates that air is sent to the exhaust manifold when the engine is started up cold. It remains there until closed loop is achieved, then switches air to the converter. There are conditions which will change this. If the car is driven during warm-up, certain conditions will cause the air to be diverted. The same conditions also will cause the air to divert after closed loop has been reached. The reason that I recommend the method above to prevent the AIR system from throwing off the w/b O2 readings is that air is injected into the exhaust manifold during any open loop period after start-up (all time delays included) provided one of those "other" conditions doesn't come into play. Also, the AIR system operates as normal during all phases of engine run except for the switching of air to the exhaust manifold (ahead of the O2). I would be happy to post the operational description of the AIR solenoids if that would help.

 

I remember seeing a divert enable temp the other day in the 6E.xdf included with TunerPro.
Didn't have time to trace it through the code to see what it did or didn't....

 

Show me. I have looked through it again and still don't see it.

The idea is not neccesarily to divert at all times. It is to keep the air from entering the exhaust stream ahead of the O2 when tuning. The method I offer allows the AIR system to provide air to the catalytic converter when it is not diverted.

I'll scan and post the operational description later so that we are looking at the same thing.

 

[IMG]e:\air1.jpg[/IMG]
[IMG]e:\air2.jpg[/IMG][IMG]pic1/e:\air1[/IMG]

 

I've tried to attach the jpg file for your review. It is too large. I am sending to vernw. If you would like, I can send it to you Z69. I just need an address. I know it is a little difficult to read, but I will be glad to help if the text is too unclear to read.