I was doing some engine bay looking/cleaning and notice the black wire with black boot that connects to the white plastic connection, was broken and just hanging. The other two white wires look fine. The car is running fine!! Good smell and color on tail pipe. Great power, car is dedicated DE machine and supplies many smiles. Also the cat is cleaned out; don't tell anyone!
Question:
Do I fix it?
Can it cause damage to DME or aything else if not fixed?
Disconnect all wires?
Leave the other two connetcted and black boot hanging?
Splice arround white plactic thing?

Thank You

 

my mechanic told me to unplug the O2 sensor on my 84 club racer. It will default the ecu to full rich, which is what you want for the track anyway.

 

looks like what you have is a disconnected O2 anyway . the white wires are the heater and the black is the signal back to the DME. just leave it,

 

It's not a issue to run without the O2 sensor but I'd unplug the other harness (O2 Heater wires) as well.

So long as the CO is set correctly via the CO screw on the Air Flow meter then you should be fine.

Also, since the cat is cleaned out no worry about clogging the cat either.

 

No biggie.

If you do replace it, buy a generic 3 wire Bosch without a connector and solder the wires. I don't know what current prices are but about ten years ago that saved me $100.

Steve
84 Targa
64 356

 

I have an '84 Targa which I purchased about 8 months ago. My O2 sensor was also unplugged - which strangely was not caught in the PPI. When I discovered the problem and plugged it in - my car started running really rough. I replaced the sensor and after a bit of work getting the old one out and the new one in - the car runs fine.

Not clear as to the value of keeping it unplugged - especially on the street....

 

Thanks for the HELP!!!

 

911 Chips has a chip that bypasses the O2 like the Euro program.

I belive in dyno testing for A/F ratios, stock or performance chip. After about 5000rpms, the AFM is pretty much of it so things like freer flowing exausts may make the car lean.

This dose not meen you need a new chip or burn as you can use the fuel quality switch on the ECU if needed.

I like the custom SW chip program where you get a chip matched to your car, have dynoed for the A/F's and Steve then reprograms the chip to fit.

Anyway, leaving is unpluged for the track is not a big deal. If your A/F's are off over 5K where the power is, it could be.

 

I crumbled mine when I replaced my O2 Sensor with a New One.

I was told to simply splice with a male ad female bullet spades. I would have done that but wonder why PAG didn't do that, then I realized that connection needed to be insulated for some reason, probably due to heat but who really knows.

My company decided to produce a replacement harness when I found out to replace the harness I would need to replace the whole wiring at $1300?!? Apparently it is whole bunch of wires connection to the DME.

 

"It will default the ecu to full rich"

A very common misconception, e.g. as posted on the other so-called "technical"
Porsche website by many, that's incorrect. The mixture could result in either a
lean OR rich condition depending upon how the AFM is set (and fuel pressure).

"which is what you want for the track anyway"

Hardly! The mixture should be slightly less than an AFR of 14.7, about 13.0.
So, no assumption should be made that the AFR will be correct (track use)
by disconnecting the O2 sensor.

 

Loren would it be fair to say the car will " atempt" to run rich ? which of course is over riden by any adjustemnts made ?
Just wondering for me own interest.

Thanks

 

"Loren would it be fair to say the car will " atempt" to run rich ?"

Nope! With no O2 sensor, the DME assumes a neutral mixture based on:
1. AFM
2. CHT temp sensor
3. throttle switches
4. air temp sensor

 

My $.02.

Thus, Fix what you have or get a SW euro style chip that does not use the O2.

What ever is done, please concider dyno and test your A/F's to make sure you are ok. There are many things that can effect them including motor components out of spec and or mods made.

If they are to high--loss of HP, if to low--may be a new motor in the future.

 

what's the hubub about an o2 sensor? If it did anything worthwhile I could understand, but it does nothing. If your idle mix is correct what purpose does it serve?

 

What part of Laf?