Hello fellow brickboarders:

I have a simple but important question.

I have been pulling my hair out trying to get my 740 gl to pass emissions. I finally replaced the o2 sensor with a universal bosch 3 wire. The problem was that it has 1 black wire and 2 white wires. The installed sensor had 1 black and 1 red and 1 white. I figured I had a 50 50 chance of getting it right. The car ran flawlessly after install, but actually the nox emissions went way up!!!

Now (before o2 sensor replacement), after installing new plugs, cleaning the knock sensor, check hoses, replacing the fuel regulator, correcting the air box flap problem (its in the cold open position, i couldn't get the little thermostat to go back in!), my emissions readings are worse than when I started (but runs 10x better)!?

Is there some simple way to test that the 02 sensor is wired correctly?

Does the higher nox reading automatically tell me that it is not.
BTW, now I can't go back to nj dmv for another test, they told me now I have to go to a mechanic.

Thanks.

you have a bendix or regina car. the universal o2 sensor doesn't work with those cars. the 02 sensor strategy is different. get the right 1 from the dealer or someplace. the right sensor will have the same wire colors and connector. good luck, chuck.

Thanks.

Man, I hope your wrong though. Although my nox reading went from 1500 to 2000. Passing is 970.

Does anyone know then is it a different o2 sensor, or is it just the connector that is different?

I found a prior thread on the wires, but it was not clear as to how you match red/white/black to white/white/black.

Thanks.

Your car (Bendix/Regina fuel injection) uses an entirly different type of O2 sensor. No Bosch sensor will work, but I think Walker makes one. Maybe NTK too.

Use the seach field below on "titania".

Here's a post on the subject from earlier this month:

posted by  tomtbone   on  Sun Oct 3 19:41 EST 2004
Author Info: [PROFILE] [EVERY POST] [THREADS]
I did a lot of research on this myself, talked to a lot of guys even the people of NGK.

I have a 91 Rex system 740
Best place is to just order it from NGK's website at www.sparkplugs.com. ITs 120 there. Don't get a universal one because it will not have the titania construction most likely and you will have to splice in the wires as well. I believe it is model 25063. Feel free to email them on their site though they email right back sometimes within the minute!
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

wagonmeister,

When posting messages you should select the model/year details underneath the subject line. By doing so your message will appear in the appropriate forum. By keeping the "ALL/ALL" your message was directed to the "RWD" forum which is pretty general (covers all Volvo cars up to 1998). I can't speak for others but when I peruse the boards I always select each model type so that I don't have to read posts about cars that I'm not interested.

I selected the 700 forum in this post, hopefully it will get posted there.

Bean
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'80 242GT 93k, '94 945T 139k, '89 765T 68k (new '94 B230FT)

sorry about that.

1991 740 gl wagon non turbo.