For tuning fuel injection or carbs I prefer a wide band over a CO analyzer. The CO machine can be tricked by spark issues where the wide band cares not about spark and only sees true air fuel ratio in the charge.

Don’t leave a wide band sensor installed and switch off the power. If the car is running the sensor must be running. Installing a sensor in a bung and using it for temporary readings every now and then will destroy the sensor.

I use mine on everything from my lawnmower to my ‘66 F100. They are awesome tools and they’re dirt cheap nowadays. I watch people on YouTube struggling with EFI diagnostics on old bosch injection systems using their nose and reading plugs and I wonder why more people haven’t adopted them yet.

I just checked eBay and they’re $150 including sensors. It’s a gift.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

It could be if it is a wide band (five wire) sensor. A switch type EGO sensor (one wire to three or four wire) doesn’t do much good. You need a UEGO unit with a oxygen pump cell inside the sensor. It makes it wide range and excess O2/CO sensing rather than total O2 sensing. They basically put a tiny catalytic converter in the sensor…that’s why they read the same pre and post cat while a regular O2 sensor will have different upstream and downstream cat measurements.

Great tools for tuning fueling on old cars. Now most new cars have the systems installed so you just get Lambda on your scan tool.

Oh yeah and I don’t always use a bung on my down pipe. On my motorcycle and lawnmower I’ll just cut a hole in a cardboard box for the exhaust pipe and put a little hole on the other side for the exit. Dangle the sensor in the box and you get a stable reading.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Ditto on using a wideband O2 sensor. Unlike the simpler on-off O2 sensors, it gives a continuous reading and doesn't need to be in hot gas so can be just stuck in the tailpipe. Indeed, there are brackets for mounting them thus in aftermarket kits (ex. LEM? forget). In my 1960's gas cars, I welded in 2 bungs so I can install both wideband and normal O2 sensors. That will let me check the calibration of the wideband.

For a simple system, you can get a lean-rich indicator. I have several from Holley I bought used on ebay. It uses a normal O2 sensor in a welded bung, with a little box for the cabin with just an LED which lights when rich and turns off when lean. I used one with a Holley Pro-jection TBI. I also have similar ones made by Onan for their LPG generator engines, I ran across cheap as clearance on ebay. They seem to have a long lag time ~20 sec, but work OK to give a rich/lean indication for steady freeway driving. If anybody wants one cheap (say $20), I have maybe 6 kits sitting a long time. At least gives you an O2 sensor and bung even if you don't use the monitor box. Shipping might cost as much.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I have some new Nissan OE O2 sensors from 07-12 Altimas. These were considered NOS which means that Nissan didn't want them and dumped them as "surplus". I just need wiring and a gauge. Projects, projects, projects.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

I found this spec for an 86 911. "0.6-1.0%
Measured at test port on front of catalytic converter, oxygen sensor disconnected"

I haven't even figured out how to lift the car yet. But I ass/u/me that an O2 sensor would screw into the test port. Then would all I need be a 12V source and a gauge to read A/F ratio which is basically voltage converted?

1/14.7 = .068 which is standard idle mixture noted in the A/F articles.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

So I just acquired a Tektronix 455 2 channel scope. Spent the afternoon tinkering with it, got both channels working along with the time base. It may have been dropped or bounced hard, pulling both the vertical amp module and the time base module out of their sockets on the main board. I've not played with the delayed time base as I've never had a need.

So if someone needs an old (1974) scope to go with their old car, have I got a deal for you. You can have this one for what I paid, $0.00! Catch is I'm unwilling to ship it. It's pick up only in south King County or I'll meet you up to 100 miles one way.

Michael

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Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

Give or take yes. I would be very careful about putting 12V directly on the sensor wires. Two of the wires or one and the case should read roughly 5 ohms. This will be your heater. If you put full blast 12V on it you can sometimes burn it out depending on the sensor. Many controllers pulse the 12v to limit the current.

If your sensor is a simple switch type heated oxygen sensor reading it out with a voltmeter/gauge will work. However a true wide band AFR doesn’t work this way. Those have a switch type sensor in a catalytic diffusion cell combined with a zirconia oxygen pump. The pump current modulates the oxygen content in the switch cell till it hits 0V. The current required to hold the switch voltage constant is the AFR. It’s analogous to the way a hot wire flow meter reads flow by holding the temperature of a hot wire in the breeze constant by running a servo controlled current through it. An AFR electronics system is a lot more than a voltmeter/gauge in other words.

The problem with these sensors is Denso, Bosch and NGK are not generous with the data unless you work for an auto manufacturer or a component vendor like Visteon or Valeo. The best is to get the laser printed part number off the side of the sensor and ask an engineer at Denso to send you the specs for reading it…then pray they respond. The second best way to figure it out is to plug it into the said Altima and read it’s signals while it’s running.

The fact that this sensor reads positive oxygen isn’t a good sign. That’s for lean burn. 14.7 is 0% excess oxygen and all the interesting power tuning happens below that (negative oxygen or positive CO).

To figure out the heater I would find the leads with 5 ohms between them. Then put the sensor on a power supply. Heat it up. If I recall correctly I’d heat the Bosch up to 500 C and lock temperature. I cannot recall the exact numbers. I think I pulsed battery voltage at 50% duty cycle.

Good luck.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles