Is it worth adding a narrow band O2 sensor and A/F combustion meter??

I'm still dialing in my '86 Power Ram but I just rebuilt the 2.6l motor and it has the bigger 38 Weber carb AND some junkyard special Hooker Headers. When I had the headers at the weld shop I asked them to weld in an O2 sensor bung so that I can add an O2 sensor and Air/Fuel combustion gauge. Is it worth messing with?

I already ordered a cheap gauge and O2 sensor from Amazon, $12 for the sensor and $18 for the gauge. I didn't spring for a wide band sensor partially because both sensor and gauge are quite a bit more money for the increased sensitivity, but also a lot of folks were complaining on the internet that the sensors often don't hold up to daily use over the longer haul. Mostly only serious hotrodders seemed to mess with them.

(I'm just a few more hours from firing up my motor from this major rebuild so I don't yet have the motor running or even the gauge installed but now is the time to go ahead and finish adding in the gauge if I'm going to use it.)

I like the idea of a crude mixture gauge because when I swapped the original carb to the big Weber I was very unimpressed with the tuning process that Weber's customer service and literature offered. I can't remember what all they had me do and how we determined what rejetting I needed to do, but it left me really kind of uncertain that my idle, midrange, or top end were actually dialed in and I needn't worry about the motor leaning out under certain scenarios???

Anybody out there have any experience with both the narrow or wide band O2 sensors and Air Fuel mixture gauges set ups? Do the less expensive narrow band sensors and gauges really give you any sort of an accurate picture that your carb is jetted in the ballpark? Or will this only give me a false sense of security? I do plan to pull a spark plug from time to time to get an idea if I'm too lean but I like the idea of a gauge that can tell me if its running lean through any portion of the power range idle through full...

Any comments/ idea / suggestion welcome!
Bill

Narrow band are older tech and are typically used to dial in idle and low RPM's. Wideband measures throughout the RPM range and is more accurate. Get a wideband.

If you have the mix roughly right then the narrow band will work, but with modding and tuning you are sometimes way out to begin with.

I have a Wego 3 and it's great, I prefer it over the innovate one I have (which admittedly is an old model, its more involved to wire in and not waterproof for motorcycles)

Pros and cons with A/F meters. I like having one as it is a good guide on where your engine tune is at but I'd also add a vacuum gauge. Both combined gives you a good picture of how the show is running. There are jetting recommendations for Webers to suit a 2.6 but to make the most of it requires modifications to the distributor so the advance curve isn't so aggressive (there isn't a specific ignition tuning guide for the ignition so it's trial and error mostly on a stock distributor)

Thanks gents. I hadn't thought about watching my vacuum but I think I have one of my dad's old vac gauges put back. Maybe I'll stick that somewhere too!

I added one to my 91 Ram 50 just to see how the computer was compensating.

The numbers move a LOT on the narrow band. Also I found the response time on the gauge is laggy... but that is what you get for $30.

It only reads as fat as 11.6 and past a 17 it mostly jumps to 20.

I did find that at most driving the computer is pretty darn close at keeping the tune between 14.5 and 13.9.


I also use a vacuum gauge. I have poor vaccum due to worn out rings... BUT I used it to set my idle by adjusting the dizzy to the highest vaccum reading then retard just a hair to avoid ping.

I also use the vaccum gauge to improve mileage at the highest vacuum number. That would also be helpful on a carb engine. Also the vaccum gauge would be better to set up your idle circuit on a carb. Did it for years on my drag car and my 65 Chrysler. Aim for the highest vacuum number while adjusting the idle circuit.

The narrow band A/F gauge was mostly cause it was cheap and I was curious, but not very helpful.

To tune your jets, you will need a wide band and I would recommend buying a set that includes the gauge AND sensor.... get a good brand also..

Thanks Can1991Ram, lots of helpful stuff.

i second that

After 2 weeks with the narrow band, I found that in open loop the computer doesn't fatten the mix as much as i thought it would... maybe 13.5.... I thought it would have been more.

Also, if I'm heavy on the gas (without it downshifting) the computer does really richen it much either... if I shift down it will drop into the 12.1 to 12.5 range until the speed catches up to the throttle. BUT.... without the shift down it literally stays near optimum when I thought it should go fat.

I really wish I could see the table as the throttle position is certainly not turning into a fatter mix... weird.

I have checked the voltages and ohms and all within spec...