Which o2 sensors do you use?

[leakyfaucet]

I've had an ongoing struggle with my o2 sensors, and I think I've narrowed it down to just defective o2 sensors.

I used some Bosch kind that I got from autozone. They fit the plugs perfect and even had the correct number of wires and all that. But they just plain don't work.

What do you guys use that you KNOW work?

 

[DTT92LX]

I got those same bosch o2s a month ago and they're workin' fine... maybe try another set?

 

[04sleeper]

I have the Bosch ones from Autozone as well and they work just fine too.

Might be another problem that you have overlooked. Did you dump the codes and come up with anything?

Also I see that you have LT's. Sometimes putting the 02 sensors down stream too far causes improper readings.

 

[jb89coupe]

I've had an ongoing struggle with my o2 sensors, and I think I've narrowed it down to just defective o2 sensors.

I used some Bosch kind that I got from autozone. They fit the plugs perfect and even had the correct number of wires and all that. But they just plain don't work.

What do you guys use that you KNOW work?

Did you always have this problem? Did you always have the longtubes?

 

[notchman90]

i have boschs from autozone as well. i get codes for my sensors b/c from what ive heard the sensors on long tubes are so far down stream that they do not get a chance to heat up. someone correct me if im wrong.

 

[leakyfaucet]

I get codes for both left and right o2 sensors failing to turn on/reading too lean. I bought the car with longtubes. The guy I bought it from did the V8 swap and had to cut the wires to one sensor because they weren't long enough. So as soon as I bought the car, I replaced the sensors. They've never worked since I've installed them about a year and a half ago. The longtubes are MAC, and plenty of people run those with no sensor problems, right? Also, if I remember correctly, the original o2 sensors are further down in the factory H pipe, about the same distance as the long tubes put them.

I'm starting to think that the guy wired something wrong at the computer. I looked under the passenger seat, and see what really looks like a computer. It has a lot of of wires that are connected with electrical tape. My Haynes repair manual says absolutely nothing about where the computer is or how to check the wiring to it. Is that my computer? Does anybody have any diagrams I could use to see if it's wired correctly? Any useful hints about how to take the passenger seat out so I can get to this thing?

Thanks a bunch!

 

[Michael Yount]

The Bosch sensors are good units - no reason to suspect the problem is with your sensors. As others have mentioned, when you move the sensors further downstream from stock location to accomodate long tube headers, that often screws up things. Chemical reactions (oxidation) continues after the exhaust leaves the chamber - and the amount of oxygen 12-18" further down the exhaust tube is different than upstream. They make a kit to 'adjust' the readings for long tubes.

Your computer should be behind the kick panel under the dash on the passenger side.

 

[leakyfaucet]

Your computer should be behind the kick panel under the dash on the passenger side.

Where exactly would that be? Sorry, I've never done anything like this. So what is this thing that is under my passenger seat? It's definetly factory. Is it the amp for the factory radio?

Also, where can I get the kit to convert the signal for the longtubes?

 

[Michael Yount]

Sit in the passenger front seat. Stretch your legs out in front of you. The "kick" panel is what you'd hit if you picked up your right leg and moved it towards your right until you hit the......the kick panel.

Can't help you with what's under your seat - see my sig. I can tell you what's under the Volvo's passenger seat. Nothing electronic, that's for sure.

 

[leakyfaucet]

Thanks. I'll check it out. I've found the diagram for the ECU. It's really crappy. I wish I had a better one.

Anyways, I don't see a wire for the oxygen sensor going into the ECU, although it does say Air Fuel Sensor. I'm assuming that's the same thing, however. So the kick panel is to the right? Now I've just got to figure out how to get in there.

 

[jb89coupe]

Where exactly would that be? Sorry, I've never done anything like this. So what is this thing that is under my passenger seat? It's definetly factory. Is it the amp for the factory radio?

Also, where can I get the kit to convert the signal for the longtubes?

The passenger side kick panel is to the right of where the passenger's right foot would be. You should be able to see the connector for the computer when you pull that off. As for what's under your passenger seat -

 

[leakyfaucet]

As for what's under your passenger seat -

Perhaps the 4 banger ECU is located there? And it was never taken out?

 

[jb89coupe]

Thanks. I'll check it out. I've found the diagram for the ECU. It's really crappy. I wish I had a better one.

Anyways, I don't see a wire for the oxygen sensor going into the ECU, although it does say Air Fuel Sensor. I'm assuming that's the same thing, however. So the kick panel is to the right? Now I've just got to figure out how to get in there.

Here's a good pinout diagram. You might also check the HEGO ground on the firewall behind the engine.

 

[leakyfaucet]

That's great! Thanks a bunch! I'll check this out right now!

 

[jb89coupe]

I think it's pretty unlikely that you're going to find any wiring problems at the connector.. that's all hardwired in the harness. Like I said I'd check the HEGO ground first (and all the grounds for that matter).

 

[Michael Yount]

Nice diagram - I think I need a tissue.

 

[leakyfaucet]

Alright, I pulled the kick panel off, very easy. Now I can see the side of the ECU where the big connecter plugs in and gets bolted down. Yeah, probably nothing wrong there. I see one ground on the inside of the car, under the carpet. Any idea what that is? It looks fine, but I'm going to pull it and clean it off anyways. I can't find the HEGO ground. Can you give me an exact location?

Also, if I can get a hold of a multimeter, is there any test I can do to see if the ECU is getting any signal from the sensors?

 

[Michael Yount]

If you're getting codes for the sensors, then they're likely hooked up. In any event, the way to check is to get the car up in the air and follow the sensor harness. They come down each side of the oil pan -- on the driver's side, it picks up the oil level indicator switch wire too. The driver's side wire crosses under/in front of the oil pan (under the balancer) and picks up the sensor wire from the passenger side. There is another plug down sort of under the alternator that plugs the sensor wires into the main harness -- and then everything goes back into the computer.

I'd be very surprised if the issue isn't related to your long tubes - it happens all the time. The stock location is WAY up by the ball/socket flange on the shorty headers. Long tubes move the sensors WAY back.

Good luck with it.

 

[leakyfaucet]

Well, I've actually disconnected the oxygen sensor harness to test it and I still get the codes for the failed sensors. The oxygen sensor harness is good BTW. Do you have any idea where the sensor ground is? I know where the oxygen sensor harness plugs into the main harness, though. And do you know where to get the kit to adjust the readings?

I'm really getting sick of 10mpg =)

 

[leakyfaucet]

I hope that diagram isn't too much different than mine. I have a 93 computer/engine and the label says 88-91...