George66Falcon
Active member
I'm hoping to install an 02 sensor for an air/fuel ratio gauge. Any tips? I'm running a 250 2v head, and I thought the screw-in vacuum fitting on the intake might be a good place to install one.
Good spot for a/f gauge?
- Thread starter George66Falcon
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62Ranchero200
Famous Member
@george66falcon,
All the a/f oxygen sensors I know go in the exhaust path. Closer to the exhaust valve is better, but unless you're a professional racer you'll probably only have one a/f and you'll want to monitor more that more than one cylinder. Mine is in one of two collectors so it monitors three cylinders.
Thanks
Bob
All the a/f oxygen sensors I know go in the exhaust path. Closer to the exhaust valve is better, but unless you're a professional racer you'll probably only have one a/f and you'll want to monitor more that more than one cylinder. Mine is in one of two collectors so it monitors three cylinders.
Thanks
Bob
George66Falcon
Active member
Oh really? Forgive me if I'm clueless! I'm hoping to install a sensor that lets me read my fuel mixture. Is that an 02 sensor that would go in the exhaust? as opposed to the intake manifold? Thanks for the reply.
X2 Air fuel ratio gauges use a an O2 sensor that gets installed in the exhaust head pipe or collector. If your wanting to use that intake Manafold tap as a sorce for engine readings you will need to hook it up to a Vacuum Gauge they are also very useful for engine tuning as well as helping you to get your very best in MPG while driving. Good luck 
George66Falcon
Active member
Ah! Gotcha. Thanks for the tip. IIRC there's a tech article on tuning with a vacuum gauge, I guess I'd better check it out 
Yes, both help with tuning.
3rd: There is a screw on the carb that mixes air to fuel also needed to be dialed in/out and left as an initial adjustment.
The vac gauge measures what you've done in ur tune helping you adjust more correctly.
The O2 gauge (modern cars have it as a computer sensor feeding back info on quality of burn gases to a/f mixtures adjustments) some of us install to use to tune more accurately.
This makes me think of these vehicles as a musical instrument - in need of tuning! i.e.: "That's a lill sharp, now a lill flat. Better go re-tune"…humm, slipping, after midnite...
3rd: There is a screw on the carb that mixes air to fuel also needed to be dialed in/out and left as an initial adjustment.
The vac gauge measures what you've done in ur tune helping you adjust more correctly.
The O2 gauge (modern cars have it as a computer sensor feeding back info on quality of burn gases to a/f mixtures adjustments) some of us install to use to tune more accurately.
This makes me think of these vehicles as a musical instrument - in need of tuning! i.e.: "That's a lill sharp, now a lill flat. Better go re-tune"…humm, slipping, after midnite...
i was thinking of using a 2x o2 sensor kit and placing them at #2 and #5 cylinders this seems like a good kit http://www.ebay.com/itm/281796482842?_t ... EBIDX%3AIT
Y so high? & Y 2?
May B 4 multi-carb set ups?
I heard ( 2, 3 yrs. ago) that 1 in the I6's down tube - a wide band/down stream/'the second', would give a good reading.
I'm thinkin by eye and ear is enuff in most our vehicles anyway (an O2 of this variety is in the $100 range, then the expense of a gauge and time of wiring & mounting both).
Possibly even lower, like past the down tube (but becoming less useful). Don't the modern vehicles have the down stream in the aft side of the cat? Still quite hot there (as needed).
May B 4 multi-carb set ups?
I heard ( 2, 3 yrs. ago) that 1 in the I6's down tube - a wide band/down stream/'the second', would give a good reading.
I'm thinkin by eye and ear is enuff in most our vehicles anyway (an O2 of this variety is in the $100 range, then the expense of a gauge and time of wiring & mounting both).
Possibly even lower, like past the down tube (but becoming less useful). Don't the modern vehicles have the down stream in the aft side of the cat? Still quite hot there (as needed).
Here's pics of AFR gauge sensor with bung welded @ foot downstream from exhaust (turbo) outlet . The AFR gauge is a Summit/AEM (@ $ 125). The old 60's carbs typically run pretty rich but as 70's emissions got added they leaned out carb circuits and played with the ign. and valve timing to try to compensate . With performance mods to motors and forced induction, Vacuum and AFR gauges are key tuning instrument for an engines' survival.
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have fun
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have fun
if you planning on using a a/f ratio guage, make sure you spend the extra money and get the wide band meter. A narrow band is really nothing more than a light show.
Chad- most all cars after 1996 will have a O2 sensor before and after the cat. The front O2 si what controls the a/f mixture via the computer. The sensor after the cat is only checking the operation of the front sensor and will only turn on the CEL if there's a issue.
The really new cars are even placing the O2 sensor within a foot or closer to the head for the most accurate reading.
On our old non computer controlled cars IMO the sensor for the a/f ratio gauge needs to be as close to the collector as possible.
If your running dual exhaust, make sure you weld an extra bung with a plug to the other collector to ck it's ratio too.
Chad- most all cars after 1996 will have a O2 sensor before and after the cat. The front O2 si what controls the a/f mixture via the computer. The sensor after the cat is only checking the operation of the front sensor and will only turn on the CEL if there's a issue.
The really new cars are even placing the O2 sensor within a foot or closer to the head for the most accurate reading.
On our old non computer controlled cars IMO the sensor for the a/f ratio gauge needs to be as close to the collector as possible.
If your running dual exhaust, make sure you weld an extra bung with a plug to the other collector to ck it's ratio too.
George66Falcon
Active member
Great info, thanks all. I have a carb that I KNOW is too large in it's current form ( I know I shouldn't have, but it was free and much more performance oriented than my little weber). I was hoping to get a good feel for where it's currently at so that I can rejet appropriately. I can get a nice smooth idle, but was hoping to get an idea of what it does when cruising.
I know I shouldn't have, but it was free and much more performance oriented than my little weber). I was hoping to get a good feel for where it's currently at so that I can rejet appropriately. I can get a nice smooth idle, but was hoping to get an idea of what it does when cruising.