o2 Sensor quick question..

1982911sc · 06-25-2007, 08:51 AM

As you will see in some of the other threads on the forum I am having some bad engine hesitation problems on full throttle...After reading through hundreds of posts I am thinking it my be the o2 sensor. Is there an easy way to disconnect the sensor without have to jack up the car and wrench the sensor head from the exhaust? Can i just unclip the wires in the engine bay and drive around for a few to diagnose? Thanks!

speedracing944 · speedracing944's Garage

You can disconnect it from the quick disconnect located at the top center of the firewall. I don't have a pic of where it is cause I am school right now.

You can get a Bosch single wire universal from a auto parts store for ~$20 which you crimp on the old wire.

Speedy

onZedge · 06-25-2007, 02:29 PM

Which car? What year (please add to your sig line). You may have a three wire O2 sensor.

1982911sc · 06-25-2007, 03:05 PM

I am sorry, I have an 86 951.

onZedge · 06-25-2007, 04:10 PM

You have a three-wire sensor. You can use Bosch p/n 13953 which is for a Ford 2.5L motor. It's cheaper than the $135 universal type - about $35-45 if you look. Just clip off the Ford connector and splice it into the old O2 sensors' harness. If the sensor is fairly new (less than 60K miles), try checking the resistance between the sensor body and the negative battery cable. Should be very close to zero ohms. I had to add a separate ground wire to the exhaust collector because I had about 6 ohms, probably due to corrosion in a 20 year old car! I wasn't about to open up a can of worms taking the whole exhaust system apart just to "clean things up".

bazar01 · bazar01's Garage

Quote:

Originally posted by speedracing944
You can disconnect it from the quick disconnect located at the top center of the firewall. I don't have a pic of where it is cause I am school right now.

You can get a Bosch single wire universal from a auto parts store for ~$20 which you crimp on the old wire.

Speedy

The 86 has a 3-wire O2 sensor.
Got one from Autozone for $54 (Bosch 15725) connectors supplied.

1982911sc · 06-25-2007, 05:06 PM

thanks all, this car is new to me and in order to test if the o2 sensor is the culprit can I just unplug it up top in the engine bay? I am not sure which plug it is? Anyone have any pics or a good description, havent been able to find a pic on the site. Thanks!

1982911sc · 06-26-2007, 09:39 AM

OK, I think I may have found the plug up in the engine compartment, is it the top dead center of the firewall right in the middle of where the windsheild is? Or is it the near the battery box sitting out in the front of the battery box kind of elevated...these are the only two round plugs I can find? Any help would be appreciated?

nynor · 06-26-2007, 01:20 PM

it looks similar to a coax plug, dead center at top of fire-wall.

1982911sc · 06-26-2007, 06:38 PM

Thanks nynor, I got it...ended up not being the culprit. The quest continues to figure this one out.

Tidybuoy · 07-02-2007, 10:07 AM

Quote:

Originally posted by 1982911sc
OK, I think I may have found the plug up in the engine compartment, is it the top dead center of the firewall right in the middle of where the windsheild is? Or is it the near the battery box sitting out in the front of the battery box kind of elevated...these are the only two round plugs I can find? Any help would be appreciated?

This is what mine looks like in my '88. It's a three wire version. By the way, when I ordered a new one from Pelican, I ordered the "CA cars only version" and that was not the one in my car (which was born & raised in CA). I asked the Porsche dealership about this and they told me that different ones were used depending on supply...

Of the two plugs in the photo, it's the one towards the rear of the car.