O2 Sensor and Fuel Filter Where Are They?

[mr.Hand]

Where is the o2 sensor and fuel filter for the 1995 geo metro? I have a haynes manual but the diagram under the hood says something different.

anyone know?

[Crvett69]

should be screwed right into the exhaust manifold with 4 wires coming out of it. fuel filter is in the back beside the gas tank by drivers rear wheel. its kinda a bugger to change unless you have a hoist. laying on your back under car you usually get soaked with gas doing it

[mr.Hand]

quick question.

is there also another o2 sensor after the cat converter?

and when you buy one do you have to get the one that has the plug adapter, or can you just buy the one with the wires. I guess you have to put a plug adapter on yourself, cuz that one is much cheaper. The OEM one is 77 dollars.

i think that i may have too lean a fuel mixture, because i am seeing lots of carbon all over the tailpipe and on the back of the car. it could also be due to the engines age as well, it has 180,000 miles on it.

i have no check engine lights though that would indicate the o2 sensor, but could it be headed south?

[91Caprice9c1]

Originally Posted by mr.Hand

is there also another o2 sensor after the cat converter?

Yes, pre-cat is for fuel trim and post-cat is for monitoring catalytic converter performance only.

Originally Posted by mr.Hand

and when you buy one do you have to get the one that has the plug adapter, or can you just buy the one with the wires. I guess you have to put a plug adapter on yourself, cuz that one is much cheaper. The OEM one is 77 dollars.

You don't have to buy OEM, aftermarket will work fine. You just have to pay attention to color codes.

Originally Posted by mr.Hand

i think that i may have too lean a fuel mixture, because i am seeing lots of carbon all over the tailpipe and on the back of the car. it could also be due to the engines age as well, it has 180,000 miles on it.

A lean mix will not do that, a rich one may. Perform a compression test, check your fuel pressure, and back-probe a Digital Volt/Ohm Meter to the blue o2 sensor wire (for four wire sensors) and ground to chassis or B-. After the engine is at operating temperature, the voltage should oscillate regularly between 0.1 and 0.9, should not go negative, and should not stay the same.

I think you'll probably find a low dry compression figure that increases with a wet re-test, indicating worn piston rings. You may also have a leaky injector.

-MechanicMatt

[Crvett69]

depends on where the car is made for, seen both on 95 metros, with and without the after cat O2 sensor. in 96 with the OBDII system they all have it but 95 seems to be luck of the draw, easy to look under car and see if it has it or look on firewall for the plug and wires going down there

[mr.Hand]

I ran the fuse diagnostic on the 95 metro, and the code came back normal based on the number of times the check engine light blinked. So I guess that is good news.

Still, would the o2 sensor still be operating poorly, but returning back a normal code?

I'd like to check it, but I am not sure how to go about testing the wires as you explain. Kinda new to that part of it.

[91Caprice9c1]

Originally Posted by mr.Hand

Still, would the o2 sensor still be operating poorly, but returning back a normal code?

I'd like to check it, but I am not sure how to go about testing the wires as you explain. Kinda new to that part of it.

Yes, it is entirely possible (especially with OBDI) that the o2 sensor is not up to snuff, and not being caught by the PCM. All you'll need to test the sensor is a good Digital Volt/Ohm Meter (DVOM) and associated leads/probes. I'll post back here after work with more clarity.

I strongly suggest performing a compression test.

-MechanicMatt

[Johnny Mullet]

Originally Posted by 91Caprice9c1

I strongly suggest performing a compression test.

I second that motion opcorn: