Need all 02 Sensors?

evan9r

New Member
Dec 6, 2007
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When I got my Mustang, it had no 02 sensors at all. It ran decent but reeked of unburnt fuel so I figured it was running rich(duh) I put 02 sensors in the headers and it helped some but still seems to have a rich smell. Do I really need the last 2 02 sensors? No cats, running a pro chamber and it has no place for the 02 sensors. How much is this hurting performance? Also my CEL is on and Ive had it read, seems like it was 6 different codes, but 2 were speed sensors or something due to not having the 5spd in it anymore. 2 others were because of no EGR. How can I make them all go away?
 
The O2 sensor are critical to engine performance and economy. There are 2 of them and you need both the RH & LH sensors. O2 sensor bungs shold be in the H pipe about 6-8" from the joint where the H pipe bolts onto shorty headers. The bungs are available at Summit or even your local NAPA or other full line auto parts store.

The way to may the codes go away is to fix what caused them. When the check engine light is on, the computer is operating in "Limp mode" with reduced performance and economy.

Post the exact code numbers and I will try to post the exact 5.0 Mustang explanation of them and how to fix them.

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.

It's about $25 from Borders.com see http://www.amazon.com/ . Select boo...very good, and I found it to be very helpful.
 
There are 4 total 02 sensors required correct? Autozone only shows 2. I already have 2 installed in my LT headers. But I noticed more plugs hanging on my cross member so I assume there would be 2 more after the cats(normally) Will the same type I used in the headers work? My prochamber didnt come with bungs but I noticed in pictures that some do and they are installed after the prochamber so I guess thats where I will put them.

Oh and I guess I need MIL Eliminators also?
 
In case you have a 94-95 V8, there are still only two O2's (every computer in the world shows 4. They're wrong).

The puter monitors the function of the sensors. If they don't have enough frequency or amplitude, the CEL can come on.

On OBD-II cars, the second set of O2's is to monitor the efficacy of the catalyzation (their purpose is not to check the function of the first set of O2's). This of course does not apply to you.

Good luck.
 
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See http://www.troublecodes.net/Ford/

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IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

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89 through 95 cars have a working Check Engine light. Watch it instead of a test lamp.

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Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.