slansing

I've been having problems with the engine of my 944 acting like it has fuel starvation in hot weather. After several attempts to fix it, a mechanic disconnected the oxygen sensor, and the car seems to run fine.

He told me I could drive it with the sonsor disconnected until a new one could be ordered and installed.

The question I have to ask is, if the car can be driven with the oxygen sensor disconnected, why is it needed to begin with?

dmjames

If you run without the sensor, the car will run as rich as possible all the time. This will drop your fuel economy notably, and could, over time, gum up your sparkplugs as well. In general, though, it just means the car won't run as well as it should.

Mike C.

True. The DME will default to a rich condition (running to lean can really heat things up in a hurry).

Laust Pedersen

Not true, it defaults to 0.5V (stoichiometric) and thinks all is good and dandy, which it may or may not be, most often not.

Laust

JimV8

You will kill the cat without the O2 sensor.

michaelathome

What people are trying to say is that it will run rich. Now weither that is good or bad depends on the situation. At startup/cold it is fine. When doing daily driving warm it will be dumping as much fuel as it can into the engine all the time.

You won't "KILL your CAT" but you will for sure shorten its life as you will be dumping unspent fuel into it at given times.

Best thing to do would be to replace the O2 sensor. IIRC it is about $20. You'll save the fuel in a tank or two.

Michael

Andial951

I have been running without my O2 sensor for a couple months now (not a daily driver but I have put some miles down and even ran at the track) and no ill effects yet....although for sure I am running rich. I really need to get that fixed......as for the cat....well I dont have one so no problem.

FRporscheman

Buy the universal oxygen sensor and splice it in, instead of buying the specific oxygen sensor for 944s. You will spend $30 instead of $130.

Bosch part number 13913
make sure it's a heated 3-wire sensor

tkacki

All You have to do is to put a 1.8k resistor into the 2 pin or 3 pin socket near big DME socket. Configuration seocket depends on year model. Refer to the factory manual/ wiring diagram. Doing this, You change the configuration to ROW with no O2 sensor. DME will read fuel direclty from memory map and everything will be fine until You get new sensor.

meewosh

Hi!

I've just bought new Bosch o2 sensor and installed it with my original, dedicated DME. (earlier w/o o2 sensor I was running on friends RoW DME).

At cold start engine surges for a moment, then idle not very clearly. The sensor is brand new and installed corretly. Voltage on a multimeter while running was 0.9 V. On my friends DME without o2 sensor engine worked more clearly, but the DME was from 89 163HP 944 and I have 150HP '87 so I bought o2 sensor and installed everything genuine for my car and it doesn't work as I've expected. .

Yabo

Hmm, that's very interesting. So, doing this would possibly be better than an 02 sensor if you don't have a cat since ROW cars had more power anyway?

joes

I punched out the cat and put 1.8K resistor in the plug where the altitude sensor is ( per Wilks) It's been like that for years. car has always ran great.

Makis

O2 sensor does not do much but makes the engine run more efficient and always optimally for economy. It also helps corrects small errors like too much or too litle fuel pressure, small errors of the AFM and temperature sensors. O2 sensor does nothing when the engine is cold or when the engine is run at full throttle (WOT). OPtimal fueling for economy is needed to prolong the CAT life but is not necessary best for performance. I am running my S2 without CAT but I have retained the O2. O2 sensor are not suitable for use with leaded fuels that are best for the engine but bad for the environment.

Campeck

ae you sure? Ive always heard that to be safe EVERY cars computer will default to as rich as possible to avoid engine damage. and when mine was broken i went from a bout 470miles to a tank to 250....i cant believe i used that much gas cause it was always at stoich.

Serge944

Cars aren't tuned to always run at stoich throughout the rpm range - it's not the ideal mixture in practice.

Running very rich can ruin a cat in a very short amount of time.