changing spark splugs and O2 sensor on a 964

[allan911]

Can a "normal" person changes all 12 spark plugs on a 1990 C4? Any tips? Is there any special tool required to change the O2 sensor?

thanks :drive:

[Loren]

Replacing spark plugs:

Unscrew spark plugs with standard commercially available socket wrench insert form Messers. Snap-on Order Nr. S 97 06 and extension Snap-on, Order No. FXW4.

1. Remove the heating blower

2. Remove the air-filter cover and filter insert

Replacing the spark plugs for the lower ignition circuit

1. On vehicles with catalytic converter, separate

the plug connection for the Lambda probe, removing the hot-air blower beforehand.

2. Push the probe cable with rubber grommet downwards through the left-hand side engine paneling.

3. Remove the exhaust system complete (separating point downstream of catalytic converter)

4. Remove the side engine encapsulation panels.

Note

1. Do not use any lubricant on the plug thread.

2. With spark plugs which are difficult to remove 146103 ve, use Special Tool (disassembly clamp) 9513, order no. 000.721.951.30

Most O2 sensors use a special 19 mm slotted socket. Most folks that sell O2 sensors also sell the sockets ($9-$20).

[allan911]

:eek: Sounds like about a 5 - 6 hour job. Can you tell me exactly where the oxygen sensor is located on a 1990 C4 and the best way to remove and replace it.

thanks

Replacing spark plugs:

Unscrew spark plugs with standard commercially available socket wrench insert form Messers. Snap-on Order Nr. S 97 06 and extension Snap-on, Order No. FXW4.

1. Remove the heating blower

2. Remove the air-filter cover and filter insert

Replacing the spark plugs for the lower ignition circuit

1. On vehicles with catalytic converter, separate

the plug connection for the Lambda probe, removing the hot-air blower beforehand.

2. Push the probe cable with rubber grommet downwards through the left-hand side engine paneling.

3. Remove the exhaust system complete (separating point downstream of catalytic converter)

4. Remove the side engine encapsulation panels.

Note

1. Do not use any lubricant on the plug thread.

2. With spark plugs which are difficult to remove 146103 ve, use Special Tool (disassembly clamp) 9513, order no. 000.721.951.30

Most O2 sensors use a special 19 mm slotted socket. Most folks that sell O2 sensors also sell the sockets ($9-$20).

[Loren]

I have never removed the O2 sensor (see red arrow) - but it sits on top of the catalytic convertor (item 6).

Item 28 in this diagram

[allan911]

Thanks Loren. Does anyone out there know the best way to get to the O2 sensor for replacement?

:help:

I have never removed the O2 sensor (see red arrow) - but it sits on top of the catalytic convertor (item 6).

Item 28 in this diagram

[68CGPlt]

I changed my O2 sensor not to long ago. I had access to a lift, which made access quite reasonable, although you could accomplish the same using jack stands at the rear lifting points. You have to remove the outer heat shield to gain access to the O2 sensor itself. I was able to remove the sensor without removing the wheel. I used a small adjustable wrench. I was fortunate that the sensor was not fused into the bung. I've read from others that you must be careful not to strip the O2 sensor. If it had been fused then I would definitely have had to have an appropriate wrench for the job.

Once the sensor was removed I verified the routing of the wires, disconnected it from the male end in the engine bay and removed it. Installation was straightforward. I used a DIY over at Rennlist (964 section) to determine the torque requirement of the O2 sensor. Thread the wire through the hole in the body to the engine bay and connect. I initially had difficulty getting the gromment that goes into the hole in the inner body in place. After messing around with it for awhile with no success, I came up with a bright idea and rubbed a little soap on the gromment and it immediately affixed into place with minimal pressure.

Sorry I don't have pics, but it is rather straight forward. I also disconnected the battery before I started.

It's getting late didn't realize this post was from two years ago.....

Edited April 18, 2008 by 68CGPlt

[magcuda]

not neccesary to disconnect battery as this will loose the adaptation of the engine and wil take a while to self adapt back