$79 5 wire O2 sensor - who has bought one?

[GasSavers_bobski]

Originally Posted by 1993CivicVX

Should I reset the ECU before I change it?

No need. The ECU gets power to maintain it's diagnostic code memory through the hazard fuse. That's why pulling the fuse erases the memory. Unplugging the ECU from the car will have the same effect.

Originally Posted by 1993CivicVX

Might this take care of the CEL?

I doubt it.

Switching the ignition off shuts off the CEL, but the error code is stored in the ECU. Aside from the 2 second bulb check, the CEL only comes on when the ECU has diagnosed a problem. If you only get a code 48 from the ECU, every time the CEL comes on, it's because the ECU has re-diagnosed a problem with the LAF sensor.
The official road test conditions for a code 48 is to drive in 3rd gear with the engine speed at a constant 1500 RPM. Give it a try - 3rd gear at 1500 rpm, cycle the ignition off and back on when the CEL comes on... I bet it pops up again within a couple seconds.

[1993CivicVX]

Originally Posted by garyhgaryh

Hey J! Why buy, it's free online! It's a great manual - the bible for our cars.
If you want, I can try to find the link for you so you can download it.
Gary

That would be great!! I don't want to wait for the cd to ship and I don't want to pay $20 for it if I don't have to. :-/

[1993CivicVX]

Originally Posted by bobski

No need. The ECU gets power to maintain it's diagnostic code memory through the hazard fuse. That's why pulling the fuse erases the memory. Unplugging the ECU from the car will have the same effect.


I doubt it.

Switching the ignition off shuts off the CEL, but the error code is stored in the ECU. Aside from the 2 second bulb check, the CEL only comes on when the ECU has diagnosed a problem. If you only get a code 48 from the ECU, every time the CEL comes on, it's because the ECU has re-diagnosed a problem with the LAF sensor.
The official road test conditions for a code 48 is to drive in 3rd gear with the engine speed at a constant 1500 RPM. Give it a try - 3rd gear at 1500 rpm, cycle the ignition off and back on when the CEL comes on... I bet it pops up again within a couple seconds.

Thanks! I will be leaving school soon and will try it then.

[garyhgaryh]

Originally Posted by 1993CivicVX

Does this look about right for the tools I will need to remove my ECU?

Anything else I might need? Are the needle nosed pliers for removing the connectors?

I don't think you need pliers ... The socket and socket wrench is probably all you need.

BTW, I updated the heater comment. check it out... since you replied before I updated it. Looking for the link for the manual.

Gary

[1993CivicVX]

Originally Posted by garyhgaryh

Hey J! Why buy, it's free online! It's a great manual - the bible for our cars.
If you want, I can try to find the link for you so you can download it.

About the CEL light. It looks like during the initial startup, ecu senses something not
right and sets a flag which is only reset when ignition is off. Once you turn it on again, ecu again checks o2 sensor but by then everything is ok (o2 warmed up).
So once on, o2 sensor light will not turn off unless ignition is off. Just a guess.

Perhaps ecu is checking the resistance of the heater circuit when cold. When cold the resistance is different than when the heater is HOT. The cold value of the heater is different than the OEM. When heater is hot, it checks out ok. Might want to check this out.
Gary

So are you suggesting that the o2 sensor may not be bad? My hunch is that it's not. I will look into it. thanks.

[garyhgaryh]

Jacinto ---
Here it is...
http://www.hondahookup.com/manuals/
You'll have to register, but it's worth it if you can get the manual for _FREE_!
Enjoy...
Gary

[1993CivicVX]

Originally Posted by garyhgaryh

Jacinto ---
Here it is...
http://www.hondahookup.com/manuals/
You'll have to register, but it's worth it if you can get the manual for _FREE_!
Enjoy...
Gary

Hah, I just found one as well! Thanks tho! 88meg file, wow.
http://www.hondacivicforum.com/m_41699/tm.htm

[garyhgaryh]

Originally Posted by 1993CivicVX

So are you suggesting that the o2 sensor may not be bad? My hunch is that it's not. I will look into it. thanks.

The sensor is not what the ecu is looking for. Something is not right during your car's check of the wide band sensor.

Lets take a stab at this. If the ECU is testing the heater resistance and it's not to spec it will throw a CEL, that's a problem. But when the sensor is HOT and the ECU is ok with it, then perhaps it is not that big of an issue since the resistance now falls into the range that is expected.

Did the mechanic throw away the old o2 sensor? Do you have a multimeter at home or use one at school? If so, can you measure the resistance of the two heater wires of the new and old sensor when cold? I bet they are off (or not close).

Now for kicks, if you are willing to do this, heat the old one up with propane or just
reinstall in your car and run your car for 5 minutes at 2k rpm and measure the resistance of the O2 sensor again.. I know the mechanic cut the wire and if there is enough wire you can strip it prior to install to measuring the resistance. Do the same for the new sensor (measure the resistance when hot vs stripping the wires on it LOL). the results I would predict is that both O2 resistance will go down and the values will be closer together. In other words, the deltas between the cold values and hot values will be smaller when the O2 sensor is HOT.

Gary

[garyhgaryh]

Originally Posted by 1993CivicVX

Hah, I just found one as well! Thanks tho! 88meg file, wow.
http://www.hondacivicforum.com/m_41699/tm.htm

You will never need us again LOL!
In fact, I predict you will be the VX guru sometime next year and thumb your nose at us! haha.

[1993CivicVX]

my mechanic is very anti-"internet people". He doesn't want to hear the advice or comments of what the guys on the gassavers forum think. First time I went to him I had copied and pasted all the different advice everyone on here had posted in reply to my questions etc and he takes the piece of paper and throws it up in the air. "Are they mechanics?" he says "If they're such great mechanics, why aren't they doing it for a living?" I tried to reason with him but given that I don't know anything about nothing, it was pretty useless. But I will try to get him to cooperate. He did throw away the connector end of the o2 sensor. I asked him if I could see him this afternoon. He said maybe he'd have time. I'm pretty confident we'll be able to dig up the other part of the o2 sensor. I actually do have a multi-meter at home, but I don't know how to use it. It has several settings. I'm not sure if the wires are long enough to reach from the o2 sensor to the ECU. I am NOT mechanically inclined and get overwhelmed by this stuff pretty easily. But I feel almost obligated at this point to make my best effort so as to not have all of you waisting your proverbial breath on me as it were.