Sorry to put up so many new posts the past few days. This is the last for a while, I promise!

Can someone please help me identify this connector plug? It is coming out of the harness by the 2 brains in the passenger foot well.

Is it a diagnostic or factory test plug?



Many thanks in advance!

 

Dang! I was just wondering about that plug. Honest. See, you aren't posting too much. By the way, I think your avatar is the best. Very nice.

 

Thanks Gregg, maybe we can both find out.

 

Isn't that the "bad gas/timing retard/don't connect me unless you want to lose power plug?

 

Ernest, The models with knock sensors don't have that. On the models that do have it, it is two wires one female spade and one male spade. My 87S4 has the plug pictured and I have not been able to identify it in the WSM either.
Just a thought. There is a provision on some cars without O2 sensor for a pot to be installed to adjust air fuel mixture. Maybe this is the connection for that?

 

I stand corrected. Darn, first mistake this year!

 

German beer, er um, oops,... beverage chiller connector.

 

has anyone checked the factory repair manual?

 

That plug is used on ROW cars with out a catalytic converter. There is a potentiometer (adjustable resistor) bolted to the controller, used for adjusting the CO level on 87 and up cars

 

Hello Steve,

Are you very confident about your ID?

My Car was delivered to Canada with cat.

If you are correct, should I have this potentiometer? I have had this S4 (in my garage) for only a few months, and have less that 500 miles on it. I don't know the service history of the car, so I have replaced almost everything. Last week I took the car for my 1st emission test with it, and it failed miserably (see thread if you wish).

I will be replacing O2 sensor, re-test, cat, re-test. Is this something else I can be tracking down?

 

Watercooler, It is my understanding that the wiring harness with this plug was used for all cars. My car also has this plug as well as the plug behind the pod for the rear fog light. If your car was delivered with O2 sensor and cats then it would not have the POT.

 

Ed, both you and Gregg K have this unconnected plug as well as me, so I feel better knowing that I am not unplugged, or missing a magic box.

Thanks.

 

Watercooler,


I am positive, the potentiometer which plugs into that plug was only used on 87 and later ROW cars with no cats and no 02sensor.

Bad 02sensors are the number one cause for failed smog test, check for leaking fuel injectors, leaking dampers or fuel regulators, any vacuum leak (false air) or a miss in the engine will be read by the controller as a lean mixture the controller( LH )will try to compensate; the result is a rich mixture.