Shorted Oxygen Sensor in a '95 993
10-30-2014, 07:29 PM
#16
Burning Brakes
If you are not convinced go to the link below and enter in your car and year to confirm:
http://www.autohausaz.com/
10-30-2014, 08:50 PM
#17
Drifting
Thread Starter
Peter thanks for the info. I confirmed through Pelican Parts that the BOSCH part number 13369 is compatible with a '95 993. I'll give it a shot and return it if need be.
10-30-2014, 09:50 PM
#19
Burning Brakes
Lots of good thoughts given above. But, there are some simple things to do to make this job easy.
1. As discussed above, start your disconnect at the connector end of the sensor. Disconnect the sensor from the car.
2, Push the grommet with the wire down through the engine tin. It's easier to handle the loose grommet from below than from above where it is under the A/C compressor. Use a long bladed screwdriver to push the grommet through the engine tin.
3. Pull the the sensor wire and grommet through the hole in the engine tin, from below the car. Then remove the grommet.You will have to remove the small clamp that holds the connector wire in place so that it does not come in contact with the exhaust.
4. You should now have the entire sensor wire and connector dangling in space below the car. Now, use a wrench or specialized socket to loosen the sensor from the exhaust system. Be aware, that with the hot environment, the sensor may be hampered from removal by some corrosion. So, you may need to use a cheater on your wrench to break the sensor loose. Then, once broken loose, it should be a non-event to unscrew the old sensor.
5. Installation is the "reverse" of the above steps. The grommet should be the last item installed after the sensor has been torqued into place and the connector has been terminated in the engine compartment. For installation ease, install the grommet from below the engine tin.
6. Note: if you have lubricating paste or choose to use some anti-seize on the threads of the new sensor, be very careful to prevent any of the lubricant from getting anywhere close to the end of the sensor.
Replacement of that single sensor should be less than 30 minutes work the first time that you do it.
1. As discussed above, start your disconnect at the connector end of the sensor. Disconnect the sensor from the car.
2, Push the grommet with the wire down through the engine tin. It's easier to handle the loose grommet from below than from above where it is under the A/C compressor. Use a long bladed screwdriver to push the grommet through the engine tin.
3. Pull the the sensor wire and grommet through the hole in the engine tin, from below the car. Then remove the grommet.You will have to remove the small clamp that holds the connector wire in place so that it does not come in contact with the exhaust.
4. You should now have the entire sensor wire and connector dangling in space below the car. Now, use a wrench or specialized socket to loosen the sensor from the exhaust system. Be aware, that with the hot environment, the sensor may be hampered from removal by some corrosion. So, you may need to use a cheater on your wrench to break the sensor loose. Then, once broken loose, it should be a non-event to unscrew the old sensor.
5. Installation is the "reverse" of the above steps. The grommet should be the last item installed after the sensor has been torqued into place and the connector has been terminated in the engine compartment. For installation ease, install the grommet from below the engine tin.
6. Note: if you have lubricating paste or choose to use some anti-seize on the threads of the new sensor, be very careful to prevent any of the lubricant from getting anywhere close to the end of the sensor.
Replacement of that single sensor should be less than 30 minutes work the first time that you do it.
10-31-2014, 12:34 AM
#21
Rennlist Member
^^^^Warehouse 33. Spend a little extra and by from a sponsor who is great to work with.
10-31-2014, 01:10 AM
#23
Burning Brakes
10-31-2014, 05:38 PM
#24
Drifting
Thread Starter
And the O2 sensor from amazon has already arrived! I placed the order at about 5pm PST yesterday and using standard free 'saver' shipping it arrived by 11am today, wow.
I'll keep you all posted on the install. Thanks again for all the advice. The RL community is priceless!
I'll keep you all posted on the install. Thanks again for all the advice. The RL community is priceless!
11-09-2014, 01:54 AM
#26
Drifting
Thread Starter
Well the O2 sensor from Amazon fit just fine. I managed to DIY the replacement this morning without even putting the car on a lift/stands/ramp. There sure wasn't much room to work with at RS+10 ride height. Also whoever installed the last O2 sensor clearly just took vise-grips or a crescent wrench to it an torqued the heck out of it until it was tight. The side of the old O2 sensor was a bit dented and out of round. The old sensor was also completely crusted/corroded/oxidized over.
After a bit of driving it around today (impromptu trip to Napa and Sonoma Valleys for wine tasting), I noticed the CEL is still coming on at start-up. Is there a certain process that one has to go through to reset the OBD1 error logs? I read something about that for OBD2 equipped 993s, but as usual the OBD1 setup seems far more mysterious.
Thanks again everyone for the advice on replacing the sensor. As recommended, I disconnected the plug side first fed the wire down and out of the engine bay and then removed the sensor for the exhaust cross-pipes. Hopefully, the OBD1 just needs to recalibrate and nothing more with the exhaust system needs replacement. I suppose the worst-case scenario is a really good excuse for upgrading to sport cats anyhow.
One last note, I got and used the special O2 socket that some recommended. While I could certainly see someone being able to change the sensor without the special socket, given how little room I had to work with and how over-tightened the old sensor was, I'm darn glad I had the socket on hand.
After a bit of driving it around today (impromptu trip to Napa and Sonoma Valleys for wine tasting), I noticed the CEL is still coming on at start-up. Is there a certain process that one has to go through to reset the OBD1 error logs? I read something about that for OBD2 equipped 993s, but as usual the OBD1 setup seems far more mysterious.
Thanks again everyone for the advice on replacing the sensor. As recommended, I disconnected the plug side first fed the wire down and out of the engine bay and then removed the sensor for the exhaust cross-pipes. Hopefully, the OBD1 just needs to recalibrate and nothing more with the exhaust system needs replacement. I suppose the worst-case scenario is a really good excuse for upgrading to sport cats anyhow.
One last note, I got and used the special O2 socket that some recommended. While I could certainly see someone being able to change the sensor without the special socket, given how little room I had to work with and how over-tightened the old sensor was, I'm darn glad I had the socket on hand.
11-09-2014, 03:45 AM
#27
To reset the CEL you can try disconnecting the battery. This should clear any stored fault codes. Then carry out the idle adaptation. On an OBD2 car the readiness monitors will get reset and an OBD2 drive cycle will have to be done.
Sent from my iPhone using IB AutoGroup
Sent from my iPhone using IB AutoGroup
11-09-2014, 02:42 PM
#28
Drifting
11-09-2014, 02:45 PM
#29
Drifting
Thread Starter
To clarify what I'm seeing, I now realize I have not been experiencing a "CEL" but just a persistent "!" indicator light. After starting up my 993 and after disengaging the parking brake the "!" Turns off, due to the e-brake lever, and then a moment later turns back on again. I then toggle the "!" switch and the indicator goes off and remains off for the rest of the drive until I turn the car off and turn it back on.
Using the "ignition-on-holding-the-gas-pedal-down" trick to prompt the OBD1 to read out error codes, I received a single hard error code for O2 sensor short.
I've already swapped out the O2 sensor, and I have no regrets doing so even if I was 100% sure the old sensor was bad because it was sure ugly and clearly on its last leg (if it was still working at all). My next planned step is to disconnect the battery and reset the memory on the OBD1 (as Bruce suggests). Hopefully that "!" will be gone for good.
-----
So I guess the point of this rant is a question: Given the "!" was illuminated but the "CEL" was not, was the computer/indicator simply displaying record of an old, prior fault or a persisting sensor fault? Is the only way to tell this by resetting the OBD memory and seeing if the code returns?
My past Pcar ownership was with a 986 and OBD2 setup, so I'm still getting use to the quirks of the older, simpler(?) OBD1 system.
Using the "ignition-on-holding-the-gas-pedal-down" trick to prompt the OBD1 to read out error codes, I received a single hard error code for O2 sensor short.
I've already swapped out the O2 sensor, and I have no regrets doing so even if I was 100% sure the old sensor was bad because it was sure ugly and clearly on its last leg (if it was still working at all). My next planned step is to disconnect the battery and reset the memory on the OBD1 (as Bruce suggests). Hopefully that "!" will be gone for good.
-----
So I guess the point of this rant is a question: Given the "!" was illuminated but the "CEL" was not, was the computer/indicator simply displaying record of an old, prior fault or a persisting sensor fault? Is the only way to tell this by resetting the OBD memory and seeing if the code returns?
My past Pcar ownership was with a 986 and OBD2 setup, so I'm still getting use to the quirks of the older, simpler(?) OBD1 system.
11-09-2014, 02:47 PM
#30
Drifting
Thread Starter
I think it's different between OBD1 and OBD2. The OBD2 needs a certain amount of idling and driving time at fixed RPMs to recalibrate properly. I think with OBD1 you just hop in it and drive it to reset the computer.