john gill

Is your air pump still connected ? it will introduce free air in to the system

dprantl

The air pump should be pumping air into the exhaust downstream of the O2 sensors, so this free air should not affect them.

Dan
'91 928GT S/C 475hp/460lb.ft

davek9

Also note: Don't ever run the engine w/ the wide band O2 installed and not powered.
This is why the Cig lighter is not a recommended power source.
It's written all over the Innovate manual, but only mentioned on the last page of the AEM manual.

Erick "loaned" me an AEM to try in the '86.5, I have an Innovate in the 85, from what I can see the AEM looks a lot simpler as the controller is built into the gauge, it also has a serial out that can run directly into a comm port w/o extra software and will give you a read out.

I'm using an "add a circuit" on the fuel pump fuse (same as the stock O2 uses) on the 85 for power, no issues after three years of running it.

KenRudd

Air pump not connected.
Just picked up diag. tools. Thanks Neil!

KenRudd

Not sure why cig lighter is bad. Car cant be running w/o accessories and cig lighter also engergized unless a fuse is blown. Am I missing something?

neilh

Ken, I forgot, but I have an adapter to give you power for the innovate that hooks directly to the jump post and chassis. Drop by tomorrow if you need it. Cigar lighter on an 86 is fuse 13 ( 25 amp) only, doesn't power anything else.

davek9

They are not a solid connection, hit a bump, bump it, etc., and whoosh, no power to O2 and engine is still running, before you know it, one trashed wide band.

KenRudd

I'm not plugged _into_ the cig lighter, I am tapped into the wires that lead TO the cigarette lighter. If I knock those loose, it going to be a pretty big bump...

KenRudd

I can still run it with the A/C adapter, right?

porscheminitech

As stated above secondary air is active on cold start up. It pumps air into exhaust and will show lean idle.
In my opinion the Aem gauge is better. Just easier to work with.

Imo000

^^^ crawl under the car and see where the air pump is hooked up to in the exhaust. Then, let me know if your theory is still valid?

Imo000

^^^ scratch that^^^. I was thinking of something else.

dprantl

Can someone explain to me why air injected at least 1 foot downstream of the O2 sensors can possibly affect their AFR readings? There is no way the injected air is going to flow upstream towards the engine, right? The air pump line connects to the middle of the catalytic converter. The OP also shows the lean condition persist at idle after the engine is fully warmed up.



Dan
'91 928GT S/C 475hp/460lb.ft

KenRudd

In other news: Some 928's still have an air pump.

neilh

Ken, I assume you mean an external 12volt source, right? If so, yes. - the O2 sensor needs to be preheated and using the cig socket does not guarantee it will be prior to starting.