1994 F250 O2 Sensor Function

Reply Subscribe

Thread Tools

Search this Thread

Aug 14, 2015 | 08:33 PM

radramrod2

Thread Starter

Senior User

Joined: Aug 2003

Posts: 239

Likes: 2

1994 F250 O2 Sensor Function

Can anyone help me understand the exact function of the O2 Sensor on my 1994 F250 w/ 351W? There is only one O2 sensor, directly in front of the catalytic converter & it looks like there are air pump tubes in each exhaust manifold. If the system is pumping in air to the exhaust before the O2 sensor, isn't it giving the O2 sensor false readings? What is the purpose of the O2 sensor then, or am I missing something?

Thanks!

Aug 15, 2015 | 08:30 AM

Conanski

FTE Legend

Joined: Jun 2006

Posts: 31,930

Likes: 1,499

From: Ottawa, Ontario

The function of the O2 sensor is the same as it is on any other vehicle.. it provides feedback to the EFI system on fueling. Where these trucks are different is with the air injection system, it pumps air into the exhaust upstream of the O2 sensor on cold starts only, once the engine comes up to temperature and goes into closed loop the computer starts looking for feedback from the O2 and diverts air injection directly to the cat or bypasses everything and pumps it back to atmosphere.