Which O2 sensor is my Primary

[Jared]

Could someone enlighten my ignorant ass as to which O2 sensor is the Primary? I'm getting an LED 01 on the ECU and my O2 sensors aren't labeled..........because that would make sense.............or they are and i'm blind. I'm gonna lie and say I haven't been driving long.

Also, is the exact fit a better choice than the universal, or does it matter? Something about splicing wires in the engine seems a little TOO safe!

Last and least........if my Cat is bad will my ECU think it's the O2 sensor?

[jasonrebellion]

o2 sensor being bad causes your car to run rich...as in too much air with the fuel. this can eventually cause your cat to plug up. if you don't have emissions testing its nothing an broom handle won't fix.

[Jared]

So I'm going to conclude my Cat is bad, but I probably should replace my O2 sensor anyway. Anyone know which is the Primary sensor? Left (drivers side) or Right (passenger side)? Anyone at all?

Any input about what type of sensor is better, or if there's a difference?

[Dr_Snooz]

Why do you think your cat is bad? Usually a bad cat will cause an exhaust restriction making you lose power. Occasionally it will start rattling. Most often you'll fail a smog inspection for high HCs. If the computer is telling you to replace your sensor, then replace your sensor but don't go changing stuff if you don't need to.

[Jared]

Here's the deal, my car is notorious for pretending like one thing is wrong and it turns out to be the other. I'm pretty sure my problem is my cat because "I do" have restriction. It's like there's back pressure and when I try to accelerate the car sputters out and has no power. At first I thought I wasn't getting fuel so i checked the pump and it's fine. I naturally replaced my filter thinking that was the issue, it improved the problem, then the problem came back. I figured it was a spark or fouled plugs so I changed the distributor cap and rotor. Problem went away, then it came back. I passed emissions in May when I renewed my tabs so i wasn't thinking exhaust issue. With the restriction and lack of power it's got to be the Cat. What confuses me is my ECU is throwing code 01. The O2 sensor is $20-$40 bucks, the Cat is $107. I figure I need to change the O2 sensor if i replace the Cat so why not. It's a cheap part.

[DBMaster]

The 89 LXi's have two sensors, side by side, in each of the splits of the manifold right below the head. They have neither primary or secondary designations. The average of the two sensors is what feeds the ECU. You need to replace both of them together. For you to get a code 1 the sensors have to be pretty much dead. Their response time gets slower over time and you miss all the deterioration because we don't have the most advanced ECU's. Then, when they get to the point pf pretty much NOT working you get a code 1.

Newer vehicles have sensors before and after the cat to compare readings and feed the ECU.

[Jared]

DB~ That is an awesome response, pretty straight forward. Maybe you can help me with two more questions?

Does it matter what "type" of sensor I get? Direct fit or Universal? I know the Universal has to be spliced into the existing plug, but that idea makes me a little uncomfortable (it's more cost effective though, $19.99 vs $32.99 for the Direct fit).

The other question is I've had an ongoing idle problem for a couple years. I touched on this in my "Sputtering/Hesitation" thread and didn't really get an answer. Basically, when I start the car it will idle high at about 3k then it drops to 500-1k. When I start driving, then engage the clutch, the idle shoots up to about 2500-3k until I come to a complete stop. Usually I can turn the car off and restart it and it will go away. It's not consistent, but it happens pretty regularly. Aside from my current issue the car runs strong! The idle issue doesn't seem to affect HP or acceleration. I think I got a reply to check my coil, but I'm not sure that's the issue. My tach doesn't bounce around or anything.

Could it be the throttle body or positioning sensor? Timing? Something else? It doesn't fluctuate. I've seen some cars where the idle will bounce from like 500 to 1500 back down to 500 and back up while at a stop or idling, mine doesn't do that. Its like the throttle is stuck open. I've cleaned the throttle body and it didn't seem to fix the issue. The cars a manual. Any ideas?

Thanks!

[LX-incredible]

Primary sensor has the white connector.

[charliekuney]

The other question is I've had an ongoing idle problem...tach doesn't bounce around or anything.Thanks!

My sister's '89 LX-i had the exact same problem, and my second '89 LX-i did that for the first time today. I'll talk to her and see what the problem was, and if she doesn't know, I'll ask the person she sold it to.

By the way: welcome, fellow Washingtonian.

[Jared]

Hey thanks Charlie! I had pretty much given up on the idle issue because it was only an annoyance. Haven't found anyone that could tell me what was wrong so i just put up with it! Let me know what you can find out. We know how the weather is out here, only so mush sunshine left! Thanks again.

[AZmike]

when I start the car it will idle high at about 3k then it drops to 500-1k. When I start driving, then engage the clutch, the idle shoots up to about 2500-3k until I come to a complete stop.

My car did this recently a few times--just before it gave me a code 2 (oxygen sensor 2). Replace both your O2 sensors and you may find that problem gone as well. Hopefully you have better luck that I did removing them. For the second one I had to pull the manifold, cut the old sensor in half, and use an impact wrench to remove it since the oxygen sensor socket was just rounding it off.

The sensor itself is the same whether you get a universal or direct fit. The universals (at least the Densos that I got) come with a small crimp connector to make a butt splice as well as a piece of heat-shrink tubing and some anti-seize. As long as the old connectors are in good enough shape to reuse it seems like an easy decision to me, but then I'm cheap.

[charliekuney]

My sister sold the car because she bought a 4Runner, so she never bothered with the problem. She thought it had something to do with the air-intake being clogged. Maybe, try that? I'll talk to this guy, Alfonso, or whatever his name is, at the local Les Schwab. He's the one who bought the Accord from my sister, and maybe he fixed the problem.

[ecogabriel]

I used a universal sensor too and it seems to work OK. If the connectors are fine it is not a big deal to reuse it. I would have used a Denso have I had more time for the smog test. Rockauto seem to have them cheap; my experiences with them have been generally positive and prices are good.

Replace both sensors and make sure you reconnect them correctly. Do not switch the connections; if you do you may experience performance problems as others have reported here.

Our cars are OBD0 so they do not monitor cat activity (OBD1 cars do not monitor cats either) Only OBD2 cars have a O2 sensor to check the converter. One sensor is placed AFTER the cat and the ECU compares the signals of the one before and after the cat to see if the cat is working.
Sensor(s) in our cars are before the converter.

[carotman]

Primary sensor = white connector
Secondary sensor = green connector

Only use NTK or Densor sensors.

[ecogabriel]

Primary sensor = white connector
Secondary sensor = green connector

Only use NTK or Densor sensors.

Do not forget to cover the threads of the sensor with anti-seize compound. That may make it easier to remove when needed later.
Some sensors come with a small packet of it; use it but make sure that it does not go beyond the threads. DO NOT put it in contact with the sensing bulb part of the sensor.

[DBMaster]

I'm with Carotman on the sensors. Don't go too cheap on them. The originals lasted a long time so why not stick with equivalent.

Idle issues are pretty sticky. In your case it could be the IACV or the fast idle valve. Of course, it could be neither. Any other opinions on this?

[Jared]

Thanks for all your input, I went ahead and got the Densor's on Rockauto.com. Now I'll keep my fingers crossed and hope the sensors rectify my problem. If not, next step is replacing the Cat.

I'm gonna surf the forums and threads, but anyone have recommendations on performance exhausts? All I can seem to find is Pacesetter with a 2.25" diameter. How good is pacesetter anyway? Things are getting crazy over here, I'm outta control with all this replacing shit!

[ecogabriel]

Thanks for all your input, I went ahead and got the Densor's on Rockauto.com. Now I'll keep my fingers crossed and hope the sensors rectify my problem. If not, next step is replacing the Cat.

I'm gonna surf the forums and threads, but anyone have recommendations on performance exhausts? All I can seem to find is Pacesetter with a 2.25" diameter. How good is pacesetter anyway? Things are getting crazy over here, I'm outta control with all this replacing shit!

If you think the cat may be next it won't hurt start soaking those bolts holding it to the exhaust with "liquid wrench" or something that helps in loosening them

[Jared]

Here's an update for those interested.

I replaced both O2 sensors, I didn't replace my Cat, and the problem had seemed to disappear. I had a good amount of power back, no hesitation or sputtering, but there was a minor amount of noticeable missing at high RPM's. Not major though. I figured maybe the ECU just needed to adjust to the new O2 sensors. I read that if you pull the Fuse labeled "ECU clock" in the engine compartment this would reset the ECU. I did that and attempted to start the car and ALL the power (electrical) was drained. I have an Optima battery so I didn't think it could be that, but it seemed like something was grounding out. The power would slowly come back and everytime I turned the key it was all drained. The battery was reading normal on its output, so I spent 45 minutes trying to track down what it could be...................turns out, the battery was the problem. Replaced the battery and the car runs great. No missing, no hesitation, no sputtering. Compression feels strong (260K on the car), and it feels like it has all of it's HP back. It's a great feeling! I had no idea O2 sensors would affect the performance like they did over such a period of time. I figured they'd just go out.

After this experience I recommend ALWAYS checking your O2 sensors. I don't have any horror stories about taking the sensors out, they were pretty easy. Just a little elbow strength and they broke loose.

On a side note~ My car doesn't fire up right away, and when it does i can smell excess gas burn off. I think this has to do with the battery though. Just a guess since I didn't have this problem with my Optima. The car always just fired right up. Hopefully this won't be an ongoing issue, I can see a new starter in my future if it is.

Thanks for all your help!

[Demon1024]

The idle while moving thing sounds familiar. leme look


My problem


fixed it with a new gauge cluster. i think it was the Vss but im not sure

[Dr_Snooz]

On a side note~ My car doesn't fire up right away, and when it does i can smell excess gas burn off. I think this has to do with the battery though. Just a guess since I didn't have this problem with my Optima. The car always just fired right up. Hopefully this won't be an ongoing issue, I can see a new starter in my future if it is.

Thanks for all your help!

Give it some time. After resetting the ECU, it will take it a little while to figure out the best way to start the car.

[LX-incredible]

When does the hard start occur?

Check the timing and advance system including the cold start (retard) solenoid for proper operation.

An old TW sensor (coolant temp sensor) can cause hard starts by giving a faulty reading. This was the case with both of my accords. Both were reading cooler than they were supposed to, causing a richer than ideal start situation... Holding the pedal down 1/4 to 1/2 of the way would usually get them to start for me.