how many o2 sensors on the p28? my obd2 car was converted to obd1 (p28) but my car has 2 02 sensors. should i only use one o2 sensor? which one top or bottom sensor? im boosting my car by the way. thanks guys

 

the OBD1 P28 only looks for one, O2 sensor, the primary one, which is the one closest to the header

 

i disconnected the secondary but cel came on but disconnecting the primary doesnt throw a cel.

 

u have the plugs backwards, thats why when u disconnected the second one it triggered the o2 cel, u need it to read from the one right by the radiator, but thats just what i would do, either o2 will work as long as they both work.

 

Do you have the wires switched?

It makes no sense for it to look for the secondary one. OBD1 cars do not come with a secondary 02 sensor.

Besides that...the primary is the ONLY O2 sensor that controls fuel curve. The secondary DOES NOT control fuel curve. So....any car equipped with an O2 sensor, 2 O2 sensors, 5 O2 sensors, or a million O2 sensors would still have the primary sensor(s) as the most important.

Does your car run like ***? If the O2 wiring is switched around and you still have a CAT, it will run like ***.

The primary should see a rich and lean sine wave at the rate of 5hz. This is a result of the engine changing from rich to lean conditions...as a result of the O2 sensor sensing a rich or lean condition. Rich condition: lean command. Lean condiiton: rich command. It's a cycle (when the car is in closed loop).

The SECONDARY should see relatively flat voltage when the car is in closed loop with a cat present. It should read relatively low. High oxygen content = low voltage.

 

i switched the wires and disconected the secondary since it is not needed but cant tell the difference on how the car is running. how many wires does the obd1 02 sensor have? my 02 sensor has 4 maybe that is the problem and yup my car runs like ***

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4dek &raquo;</TD></TR><TR><TD CLASS="quote">i switched the wires and disconected the secondary since it is not needed but cant tell the difference on how the car is running. how many wires does the obd1 02 sensor have? my 02 sensor has 4 maybe that is the problem and yup my car runs like ***</TD></TR></TABLE>

the OBD1 sensor has 4 wires. If you get a P28 and your 02 sensors are wired correctly, it just ignores the 2nd sensor without any other mods.

You're also going to need OBD1 injectors and clips.

Do you have a cat.

What engine.

What year car.

 

i have a 97 civic, d16y8 bottom, d16 head, p28 ecu, dont know what obd injectors, dont know what distributor. what distributor should work with my car? does the y8 bottom and z6 head match? dont know whats wrong wit the car it just runs like a junk

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4dek &raquo;</TD></TR><TR><TD CLASS="quote">i have a 97 civic, d16y8 bottom, d16 head, p28 ecu, dont know what obd injectors, dont know what distributor. what distributor should work with my car? does the y8 bottom and z6 head match? dont know whats wrong wit the car it just runs like a junk</TD></TR></TABLE>

Use an OBD1 distributor. Yes, the heads match up fine. You gotta find out what injectors and all that.

Just take it somewhere dude. Save yourself the headache. If I lived around you, I wouldn't mind taking a look at it, but honestly, it's hard to E-fix a car that I know nothing about.

 

Check you CEL, see if its primary O2 or O2 heater. Or at least post the code, whatever it is, we can't diagnose just a yellow light.

 

my car doesnt throw a cel anymore it is just slow. im thinkin it might be the injectors or the distributor.thanks guys for the help