Well I got the new cat and exhaust in and on the drive home from my brothers I hear a pop noise under the car and the "check engine" light comes on. The wires were ripped from the o2 sensor. Now I got to pony up for one of them. I still have the wires, could I use a generic type? anyone done this?

Thanks
Paul aka "bonehead"

I got lucky the time I screwed up.

The drive shaft just rubbed a little bit of the insulation off, grounded it, and then set off the "Check Engine" light.

A little electrical tape and a heat shrink tube later and I was all set. I made sure I routed that wire and all others afterward very close to the car's body.

Live and learn!
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If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 248K looking forward to 300K badge (or sticker??). >>You haven't really worked on a car until you draw blood<< :-}

YOu mean not tie up the wires and have them rip off. ? Yean I did that.
Then I wired on a generic sensor.
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744 & 745 GLE's (IPD a-sbars)16v M46, 245 SE(IPD a-sbars) auto, 242Ti M46(IPD springs and bars), 745GL 8v auto

ok but here is what sucks- I replaced the O2 sensor with a junk yard sensor and got the "check engine" light saying it was the O2 sensor, tested it and go a reading between 0 volts and .04 volts, replaced it with brand new two-hundred-freakin'-dollar unit, drove nearly ten miles with no problems and then my wife drove 1.5 blocks and gets the "check engine" light. Code is 2*3*2, rich mixture which isn't supposed to trip the light and I can't get the code to clear.

No other code.

Also I can't get the code to clear. Several non-Volvo people suggest the computer needs some time to clear the code. Sounds bogus but I am throwing it out there.

I did NOT get an O2 sensor code this time...

frustrated in Dallas

Check your O2 sensor harness for cuts or kinks... all the way from the sensor to the ECU. If that is good, well, your ECU (especially if it is a 561 if I remember correctly) is HIGHLY suspect.

jorrell

ps. I'm shooting from the hip on this one!
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92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

That is a good idea, I, of course, dealing with any and all engine management problems, will immediately suspect the ECU -especially if the codes won't clear...

But also you will remember I had a HOT no-start problem, I replaced the fuel check valve, as we determined (do a search with my name for that saga) and had another hot no start problem since then, which only makes for more doubt towards the ECU.

pooh!

paul

Okay, here is where it is at, I still have the O2 sensor code. I have cleared it a couple of times and it always comes back. I haven't gotten the rich/lean code today.

I tested the new sensor and got a around 0.57 volts, so based on that, the sensor seems to be alright.

I tested the connection to the ECU. With the sensor connected, I am not getting continuity. The Bentley book says I should. When I tested the wire from where the sensor connects to the ECU I do have continuity so its not in the harness. There is a good ground from the Cat and at the body of the O2 sensor.

Is it a bad sensor? I am getting the correct voltage reading with the engine running but not continuity.

help please.

Thanks

The O2 sensor (at least the type used on yours) is essentially a 'binary' device, and should not stay at one voltage level for any length of time - it should toggle between roughly 0.1 and 0.9 volts. The ideal fuel/air ratio is indicated by 0.45V reading at the sensor. But since the engine management is not capable of maintaining that perfect mixture for any period of time, the mixture will constantly pass between rich and lean, with the long-term average O2 reading being 0.45V. Depending on the response of the meter you are using, this may be hard to see; it might just look like the voltage is bouncing around.

You can not really test 'continuity' of the O2 sensor; it is a high-impedance voltage-generating device, and not a resistance-variable device (like a temperature sensor), so you can not use an ohmeter to test the device itself. But regardless of what voltage appears on the sensor output, the same voltage should be present at the ECU connector as well.

Also keep in mind the ECU does not go into closed-loop mode until the engine is warm, so the O2 sensor will likely be stuck at the high- or low-level when the engine is cold. When the engine (and exhause and O2 sensor) are warm, the ECU accepts the O2 sensor as valid and uses it to fine-adjust the mixture. But again, the O2 output should not stay at 0.57V as you indicated.

Hope that helps

I have used a Bosch 13913 three wire sensor and crimp the old Volvo connector on. Cost is less than $40 at Autozone. Dan