Advice on Air/Fuel Ratio Gauge Kits

[Supertrunk]

I've been thinking of adding an Air/Fuel ratio gauge to my 81 CJ7 , but the more I shop the less I know..................

Any first-hand advice and experience with the various kits would be appreciated. I think I like the numerical read out gauge layout (like the Innovative Motor Sports) better than the multiple lights style (like the K&N), but would go either way.

Thanks!

 

[jasonmark1993]

You are looking for a wideband setup. They are used for tuning purposes. Most people only install them on boosted setups so you can monitor your AF at all times and shutdown if a problem occurs.

Im trying to remember the brand I had in my turbo car, but I know innovative is a popular one. It will come with a gauge and a sensor that is identical in appearance to a regular 02 sensor. The one I had was numerical but it also had a warning light if you went too lean.

Do you intend to rejet your carb if its off or just curious why you want one.

 

[Supertrunk]

I just put a Weber 32/36 DGEV in my '81 CJ7 . It's got the AMC 258 i6 / 4.2l six, with headers, minimalist smog equipment (just the air pump and EGR valve), a torque cam, 2 1/2" exhaust with high-flow honeycomb cat and turbo muffler, and I'm right at sea level here in Houston.

I've got the idle set pretty good, it transitions OK, then part throttle to full throttle is driving me nuts.

Before I spent a small fortune on brass, (air correctors and emulsion tubes), I thought the A/F gauge might be money well spent..............

 

[tarry99]

I just put a Weber 32/36 DGEV in my '81 CJ7 . It's got the AMC 258 i6 / 4.2l six, with headers, minimalist smog equipment (just the air pump and EGR valve), a torque cam, 2 1/2" exhaust with high-flow honeycomb cat and turbo muffler, and I'm right at sea level here in Houston.

I've got the idle set pretty good, it transitions OK, then part throttle to full throttle is driving me nuts.

Before I spent a small fortune on brass, (air correctors and emulsion tubes), I thought the A/F gauge might be money well spent..............

Part throttle to full throttle is doing exactly what?

If your talking about acceleration and how it transitions through the gears........that could be a host of other tuning issues rather than a lean or rich cycle. Like timing and its curve along that RPM range and also gear ratio's.......trying to isolate and improve upon a specific RPM related rich/lean condition while driving without a data recorder and sensors attached to the engine for RPM ,EGT's in the exhaust ,timing and throttle position for comparison may prove impossible............Most use these units as a wide open throttle sensor on a turbo charged motor to see if they run lean during that Hi Boost & RPM period.

 

[Supertrunk]

I don't think I'll be changing gear rations as a tuning aid.....................

This is a stock BBD to Weber swap no other changes, the issue is transitioning from part throttle to full throttle on the single barrel and then completely falling on it's face when the second barrel opens, or when mashing the pedal.

It was WAY lean with the factory jetting. I've got the idle mixture set, and the initial transition close on the 32 side, ( by going from a 60 to a 75 primary and a 60 to a 70 secondary idle jets and from a 145 to a 200 primary and a 145 to a 185 secondary main jets). An emulsion tube change help a lot too (from an F50 to an F6 primary).

Doing steady-throttle plug pulls, stepping through the RPM range 500rpm at a time, is getting old, and I was thinking fuel monitoring to reduce the guestimating. Then it's which jet or jets to order next, wait a week to ship, then test again.

Timing is pretty close, ring around the electrode about .5mm down, and the anneal on the ground strap is just before the bend, so I think it's just jetting. When I go from good color (slightly "crystalized" dry soot on the threads/ light orange-tan 1/3 up the base in the shell and a orange-tan ring around the electrode) at 1000, 1500, 2000, to bone white all the way to the base of the shell at 2500, I'm pretty sure it just went lean............

 

[jasonmark1993]

EDIT: you posted while I was typing; looks like you are on your way to nailing it.

Above is correct.

Let us know what it is doing.

My guess would be that you are getting a lean tip in stumble.

Like if you are at cruise/part throttle and you try and accelerate there is a stumble or hesitation and then it picks up?

You would be able to see this on a wideband but I don't know if spending a few hundred bucks on one would be worth it. I would just overjet it to see if that fixes it and go back down to where it doesn't.

On naturally aspirated vehicles, a hair lean makes the most power at WOT.

 

[tarry99]

I don't think I'll be changing gear rations as a tuning aid.....................

This is a stock BBD to Weber swap no other changes, the issue is transitioning from part throttle to full throttle on the single barrel and then completely falling on it's face when the second barrel opens, or when mashing the pedal.

It was WAY lean with the factory jetting. I've got the idle mixture set, and the initial transition close on the 32 side, ( by going from a 60 to a 75 primary and a 60 to a 70 secondary idle jets and from a 145 to a 200 primary and a 145 to a 185 secondary main jets). An emulsion tube change help a lot too (from an F50 to an F6 primary).

Doing steady-throttle plug pulls, stepping through the RPM range 500rpm at a time, is getting old, and I was thinking fuel monitoring to reduce the guestimating. Then it's which jet or jets to order next, wait a week to ship, then test again.

Timing is pretty close, ring around the electrode about .5mm down, and the anneal on the ground strap is just before the bend, so I think it's just jetting. When I go from good color (slightly "crystalized" dry soot on the threads/ light orange-tan 1/3 up the base in the shell and a orange-tan ring around the electrode) at 1000, 1500, 2000, to bone white all the way to the base of the shell at 2500, I'm pretty sure it just went lean............

No Questions gear ratios as a tuning tool play an important part to get the vehicle to accelerate & transition.
All motors when put under a load as would be the case when either shifting gears or mashing down on the gas pedal will detonate briefly until the fuel supply catches up with the load & demand. This period would be a Lean consequence if ever so briefly in some cases!
I would look at fuel supply.........fuel pressure, float heights, and your accelerator pump. If there are different size accelerator pumps available or a different ramp for the pump those should also be considered for change.
Changing Jets to cover a rich / lean event at a given RPM range is a real reach without some circuitry that would allow for air bleeds to cover that transitional circuit.........as the jet change alone effect's the complete range.

Good luck on that one!