O2 sensor shot?

[flatsixjunky]

Hello everyone,

Finally the weather permitted for me to install my new Euro pre-muffler. I started today and even if it's a pretty straight forward installation it's not achieved without some sweat, those rusted bolts are pretty stubborn.

These 2 bolts on the inside and close to each other took the cake:



Only two of the outside bolts came off using an angle grinder, for the other four I used the Dremmel tool and a Chisel.

This is a pic of the inside of the exchanger, I have a noob question, notice the reddish or rusty color, is that normal?



Here's a pic on my O2 sensor, I could not get it out. I bought the removal tool from our host and I didn't realize until too late that I wasn't placing the tool deep enough on the O2 sensor so I believe I actually ruined my chances of getting it off. The tool no longer takes hold of the sensor.

Here's a pic:



Tomorrow I'll give it another try on a bench, if not I'll have to buy another one ASAP.

Last pic, the Euro pre muffler.



Take care people.

-Orlando-

[aadrew10]

I'd get the sensor off with a pipe wrench, and then get a new one.

[flatsixjunky]

Hello Andrew,

I'll try that tomorrow, I'm ordering a new one anyway, let's face it it's 20 yrs old. But in the meantime I would really like to take it off and be able to run the car next week. I'm in STILL in the process of getting my Euro tags, and next week I have a visit for the final approval. It has taken me almost 7 months already to register this car here.

-Orlando-

[RichHawk]

Your car will run just fine without the o2 sensor. (89 3.2L with motronics)
the O2 sensor just trims the fuel map. Mostly for emissions. IF you run without one for too long, the Catalytic converter could get over hot and start melting down internally. But you don't have that worry any more with the Pre-muffler.


Just plug the o2 Hole while you wait for the new sensor.
Lastly if you want to get a universal sensor go to the local parts house and get one for a 1986 Ford Taurus (unverified but read it here). Just make sure it's a Bosch 3 wire and splice and solder it together.

Richard

[don gilbert]

Depending on your climate, you dont necc. have to have a heated 02. $$$ You can get a bosch 1 wire at any Oreiillys for 19 bucks and it will work fine.

[dicklague]

these older sensors are pretty much the same. One wire is the sensor signal itself, and the other 2 are for the electrical heating coil in the sensor. You can duplicate the original connector or anything that will get the wiring right.

They produce 0 to 1 volt signal back to the FI. that is it. all the same whether Bosch, Ford, or whatever. Mostly the same thread size.

The newer wideband sensors have 5 wires. They add a pump circuit in the sensor.

[rusnak]

Be careful when you disconnect the sensor (yellow plastic plug) in the engine compartment. These things are known to crack. The plastic itself does nothing, and can be re-glued back together. Take care not to damage the wiring.

If your O2 sensor is the original Bosch, and the wiring is in good shape, then you have the option of buying the generic 3-wire and crimp (not solder) the old connector wires to the new O2 sensor, or buy an original Bosch 3-wire sensor (the other two wires operate the heater circuit). The reason for the heater in the O2 sensor is that the O2 sensor needs to be very very hot in order to work properly.

I would be somewhat curious at least as to why your exhaust seems to be so rusty on the inside. It's as if there is excessive moisture in the exhaust. Strange.

I would not run the car without a properly working O2 sensor because it will run in safe mode, or according to a pre-programmed map (open loop) rather than use all of the available parameters to adjust timing, and fuel ratio. You will get poor gas mileage, the car will run rich and make a lot of exhaust fumes, and may have poor performance. The L-Jetronic system is fantastic when everything is working, and gives you a lot of performance.

[dw1]

I also changed over to a euro premuffler (mine's an '87) and had trouble getting the O2 sensor off of my old cat.

I finally did get it off, but I decided it was better just to get a new 3-wire OEM-style sensor. They are available from our sponsor, of course, but I got mine at a nearby FLAPS (Advance Auto Parts, if I recall). From either source, the price vs effort trade-off (and risk of it being non-functional) is worth it, IMHO.

It hasn't been dyno'd, but I think my '87 3.2 (w. 93 oct. SW chip, euro premuffler, & Dansk 1-in-2-out) runs better with the O2 sensor than without it.

It would be interesting (and it probably has been discussed here before) to test the air-fuel ratio with vs. without the O2 sensor when using a premuffler in place of the cat.

[flatsixjunky]

Hello,

Rich, don and dick thanks for the info, I thought it was a big no-no to run the car without the sensor. I'll be able to wait for the new one while still being able to pas the gov inspection. Great news.

Today it rained all day, I wasn't able to finish. I took the muffler tip out and cleaned it with a metal brush, I then primed it and applied a first coat of black, I'll give it two more coats before reinstalling it.

And a gratuitous pic:



Can't wait to run it with the new setup. I believe the car will run better now without the cat. I think it's clogged. I tried placing a hand held lamp on one end of the cat to see if I could see anything on the other side and nothing. Maybe it was already time to replace it.

Take care.

[flatsixjunky]

Hello,

I would be somewhat curious at least as to why your exhaust seems to be so rusty on the inside. It's as if there is excessive moisture in the exhaust. Strange.

from rusnack

It looks like moisture has been present although the interior of the heat exchanger was completely dry. The moisture visible on the gasket face it's one of those spray's used to loosen rusted bolts. I have ran the car a few times during the winter and it has always reached at least 210f.

I would not run the car without a properly working O2 sensor because it will run in safe mode, or according to a pre-programmed map (open loop) rather than use all of the available parameters to adjust timing, and fuel ratio. You will get poor gas mileage, the car will run rich and make a lot of exhaust fumes, and may have poor performance. The L-Jetronic system is fantastic when everything is working, and gives you a lot of performance.

from rusnack

Can I run the car once or twice? The new O2 sensor won't get here before the date of the inspection. I'm going to try some locking pliers on the one I have and if I can get it out I'll put it in until the new one get's here. Thanks for the advice.

I finally did get it off, but I decided it was better just to get a new 3-wire OEM-style sensor. They are available from our sponsor, of course, but I got mine at a nearby FLAPS (Advance Auto Parts, if I recall). From either source, the price vs effort trade-off (and risk of it being non-functional) is worth it, IMHO.

from dw1

I want to put a new one I just have to use the car on Wednesday and if I can't get the old one out I might have to run it for a few miles without it. Thanks for the advice.

Are there any serious and immediate risks of doing so?

Thanks.

[don gilbert]

on a motronic car, the 02 sensor is the tattletale of the whole fuel system, constantly monitoring the mix at idle and part throttle, it has no effect at wot, as the system goes into open loop (not working) so it has no effect on wot performance. with it disconnected, you fuel mileage wont be so good cruising down the hwy, and will prob. be a little rich at idle, which isn't good for anything, plugs, rings, oil and the air. Carbs are what used to wear out rings and bearings at 100,000 mile. Now with such precise fuel metering avaiable because of the 02 sensors, engines can go 300,000+, and that just half a$$ taking car of them.

[dw1]

I ran mine both with & without a functioning O2 sensor.

Without a functioning sensor, my AFR meter showed a rich idle, and there was a bit of a stumble (or "bogging") with initial throttle application.

Drivable without the sensor functioning - sure, but I wouldn't want to drive it hard, or for a long period at steady highway speed.

BTW, do you have a plug to put in if you can't get the old one out? I certainly wouldn't run it without something plugging the O2 sensor hole in the premuffler, just because of the exhaust gas leak. The O2 bung is standard size thread (M18 x 1.5, I think) and a plug (or cheap sensor which you can use as a plug) may be available at a local auto parts store.

[flatsixjunky]

Don,

thanks for the info.

dw1,

So if I do have to drive it without it, it should be not to hard and for not too long on the highway, right? If I do it would be the one time, I should be able to get away with it.

Thanks to all.

[dw1]

Originally Posted by flatsixjunky

So if I do have to drive it without it, it should be not to hard and for not too long on the highway, right? If I do it would be the one time, I should be able to get away with it.

Assuming the premuffler bung has an appropriate threaded plug, IMHO - yes.

[flatsixjunky]

dw1,

Yes, the pre-muffler O2 bung came plugged, sorry I forgot to answer that one. Btw it'a fabspeed. I know now that the general opinion here is that M&K is better. I did not knew that when I ordered mine. Well, la-di-da.

Take care.

[rusnak]

I didn't mean to imply that the engine will blow up if you drive it without the O2 sensor, just that it will run rich. An old sensor will send weaker voltage, which will also make the dme think the engine is leaner than it is, so an old O2 sensor will also produce incrementally richer mixtures as it ages.

Bottom line: replace the O2 sensor every few years with a quality one. Do not solder the wires, use a crimp if you go with the generic or universal 3-wire from Bosch.

The Fabspeed bypass has a cap on it. It's not plugged. Use an allen wrench to remove the cap, and put it in a safe place where you will find it in the future. The Fabspeed one will work just fine. I think they probably fixed their fitment or jig issues.

[flatsixjunky]

Do not solder the wires, use a crimp if you go with the generic or universal 3-wire from Bosch.

from rusnak

Would you mind explaining why?

The Fabspeed bypass has a cap on it. It's not plugged.

from rusnak

Sorry, that's what I meant to say.

Take care.

[don gilbert]

I have no evidence to back this up, but was always told that the solder will affect the millvoltage travling the wire. Is it true?? i dont know for sure but i have alway crimped mine and had no probs.

[rusnak]

You can try soldering it, but the solder does not want to stick. And for applications that take a lot of vibrations, crimping is the way to go. Use quality crimps. I think the sensor wires are steel or something. I ran into the same problem soldering a dental instrument for my dad. I was ready to crimp with a telephone wire crimp connector, but my dad is old school and just had to use solder. So, I guess you can do it but it may come undone and cause you problems later.

[rusnak]

Originally Posted by flatsixjunky

Hello,

Rich, don and dick thanks for the info, I thought it was a big no-no to run the car without the sensor. I'll be able to wait for the new one while still being able to pas the gov inspection. Great news.

Today it rained all day, I wasn't able to finish. I took the muffler tip out and cleaned it with a metal brush, I then primed it and applied a first coat of black, I'll give it two more coats before reinstalling it.

And a gratuitous pic:



Can't wait to run it with the new setup. I believe the car will run better now without the cat. I think it's clogged. I tried placing a hand held lamp on one end of the cat to see if I could see anything on the other side and nothing. Maybe it was already time to replace it.

Take care.

Hold on, you're installing a Steve Wong chip? Then you have no choice but to install a working O2 sensor, or you'll get absolutely zero use from the chip, unless Steve re-programmed the default map as well. If you don't install the O2 sensor, then it'll run like you installed a chip that was programmed for 85 RON, and you will be not happy.