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Air/Fuel Gauges options for an engine with a carburetor

4xfun

Jr. Member
Joined
May 16, 2005
Messages
76
Are there any recommendations on a Air/Fuel Gauge Kit to be used on a 69 302 with a carburetor? I know that you can read spark plugs and get close, but I would rather have a quicker reading so that i can see the difference as modifications are made. I am running rich right now and need to adjust the jets, but don't want to get it too lean. The previous owner supposedly had the engine rebuilt with some performance additions, but when I got it, there were very few performance items on the exterior of the engine. Based on the lope at idle, it may have a hotter cam. It has a Holly 500 2 barrel carb with cast exhaust manifolds. Stock distributor and points. Not sure about the heads. It is typically just used on the road with light offroad use. Currently I am cleaning up the wiring, so I can't run it and check the vacuum reading. I realize that the timing needs to be adjusted correctly before making any calls about changes and that part of the issue may be with the carb and or the cam.
 

m_m70

Contributor
Sr. Member
Joined
Jun 14, 2001
Messages
1,459
Loc.
Pacifica, CA
I run two AutoMeter 3579 (one for each bank) with the O2 sensors in each header just passed the collector. Easy to setup/wire in and plenty of sensor wire length.
 
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4xfun

Jr. Member
Joined
May 16, 2005
Messages
76
Have they been useful? It does not seem to be difficult install and not a like a lot of money to help monitor the engine condition
 

surfer-b

Contributor
Bronco Guru
Joined
Sep 7, 2006
Messages
2,972
watch this vid, you may be able to watch and figure out which APP he is using or contact him. This guy is knows his mechanics

 

BroncoJimbo

Contributor
Long-term owner
Joined
Jun 11, 2014
Messages
193
Loc.
North GA
I run one in my Mikuni equipped Triumph. It has been very helpful in tuning these carbs which were never meant to be on a car.
I run two AutoMeter 3579 (one for each bank) with the O2 sensors in each header just passed the collector. Easy to setup/wire in and plenty of sensor wire length.
Not sure why you would need one for each bank when you just have the one carb.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
One in one bank is all that is needed for general tuning. Get into big race engines and they will do one per cylinder to fine tune the cylinder to cylinder distribution. But that is EFI stuff where you can do minor injector offsets.

Yes, they are great tuning aids. Few people actually have the ability to fine tune all the little bits of a carb off sights, sounds, and smells.
If you have the access to Motortrend, Roadkill garage, Season 3, episode 29. they do a carb tuning show using a wide band.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
I bought an Innovate Motorsports wideband air/fuel gauge, and mad it portable, so I could use it in my other vehicles. I mounted the gauge on a board, and for power, it just plugs into the cigar lighter. When you're done tuning, you just disconnect it, and put a plug into the O2 sensor bung. I also ran a long vacuum hose into the passenger compartment so I could identify which of the carb's circuits I was monitoring at that time.
It works great for tuning and made my 302 smell a lot better. but a bit of warning... you're just looking at an average for the four cylinders in that bank. If you tune for the optimum 14.7 ratio, you may have a lean condition on one or more cylinders, so give it a bit more fuel for safety.
https://www.summitracing.com/parts/...c6dTersUoT2GS-FVE5fz9uaxQ5jKVd-8aAgY7EALw_wcB
 
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4xfun

Jr. Member
Joined
May 16, 2005
Messages
76
I was already thinking about the portable option. I could run the wires through the gearshift boot for a short period until i decide if I want to make it permanent. What little bit of reading that I have done, a permanent fitting near the end of the exhaust manifold would work bettery tha a temporary mount in the rear of the tailpipe. Apparently you get some air intrusion and it throws the numbers off
 
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4xfun

Jr. Member
Joined
May 16, 2005
Messages
76
watch this vid, you may be able to watch and figure out which APP he is using or contact him. This guy is knows his mechanics

Thanks for tricking me into watching this guy for a couple of hours. Very informative. Maybe someone on this site will see if they can make their bronco run with a lawn mower carb.
 
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