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tholyoak · 01-25-2008, 09:58 AM

All cars use only 4 o2 sensors. 2 pre cat and 2 post cat, the precat sensors are used to determine the mixture under closed loop and the post cat are for emissions. The ROW cars have no post cat sensor.

If you have cats in the headers, you have a sensor pre and post this cat. There is no O2 sensor post the midpipe cat on these cars. These cars have a total of 4 cats

if you have no cats on the headers you have one cat in the midpipe, and the o2 sensors are pre and post this cat.

The 5.2.2 DME, the 7.2 DME and the 7.8 DME only have input for 2 o2 sensors per bank.
In your illustration there is no o2 sensor post that cat on the later cars that can use those bypass pipes, as the cat is in the header, thus no wire to leave hanging.
Todd

01-25-2008, 09:58 AM	#6
tholyoak Registered User Join Date: Jan 2006 Location: Glen Allen, ON Posts: 314	All cars use only 4 o2 sensors. 2 pre cat and 2 post cat, the precat sensors are used to determine the mixture under closed loop and the post cat are for emissions. The ROW cars have no post cat sensor. If you have cats in the headers, you have a sensor pre and post this cat. There is no O2 sensor post the midpipe cat on these cars. These cars have a total of 4 cats if you have no cats on the headers you have one cat in the midpipe, and the o2 sensors are pre and post this cat. The 5.2.2 DME, the 7.2 DME and the 7.8 DME only have input for 2 o2 sensors per bank. In your illustration there is no o2 sensor post that cat on the later cars that can use those bypass pipes, as the cat is in the header, thus no wire to leave hanging. Todd __________________ Current Cars: 1989 911 Targa 1984 944 Original Owner 1971 911T Last edited by tholyoak; 01-25-2008 at 10:02 AM.