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Who Has Experience With AEM Air/Fuel Gauge?

Dibbons

Dibbons

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About to install a 340 to replace the 318 in our '72 Satellite Sebring Plus. May start it up using the Carter two-barrel and install the thermo-quad later. I have an AEM air/fuel ration gauge collecting dust on the shelf I would like to use (model 30-4110. I would like to know somehow who has experience with this type of monitoring because I don't want to run too lean on cruise a damage the internal engine components. Thank you. (posted on FABO also).

IMG_0255 2.JPG
 
I have one. It is quite the eye opener how an engine swings wildly from rich to lean just during regular operation.
I installed mine over 10 years ago to help me with a detonation problem that I was dealing with. One thing that I learned the last couple years is that the goal of 14.7 ratio is based on 100% pure gasoline but when you only have ethanol gas to use, the numbers change. We have "up to 10% ethanol" here as stated on the gas pumps so if the ethanol levels are indeed 10%, the goal number changes to around 13.8 to 1.
 
Agree with Kerndog and even at that I target high 12 low 13's for a ratio. Every adjustment you make will affect everything else. An engine will survive running rich every time. It'll survive lean a few times.
 
Run the afr's at whatever the motor likes weather it be 14.5 or mid 13's. But your plug reading will have the final say as to where the afrs should be for optimum performance.
 
Bosch 17205 is a good O2 sensor to use.. I got mine from Rock Auto, much cheaper than what FAST wants for same thing
 
Kern Dog said:
I have one. It is quite the eye opener how an engine swings wildly from rich to lean just during regular operation.
I installed mine over 10 years ago to help me with a detonation problem that I was dealing with. One thing that I learned the last couple years is that the goal of 14.7 ratio is based on 100% pure gasoline but when you only have ethanol gas to use, the numbers change. We have "up to 10% ethanol" here as stated on the gas pumps so if the ethanol levels are indeed 10%, the goal number changes to around 13.8 to 1.
Click to expand...
Great info here, I didn't know about the 10% ethanol the goal number changes. Pretty much all the gas here is 10% ethanol around me, unless I wanna buy the "clear" gas for 6$ gallon.
 
Belvedere408 said:
Great info here, I didn't know about the 10% ethanol the goal number changes. Pretty much all the gas here is 10% ethanol around me, unless I wanna buy the "clear" gas for 6$ gallon.
Click to expand...
Yea, I have to drive over an hour to get into eastern PA to get 90 octane ethanol free for my mower and snowblower. But it's worth the trip pulling one time on the cord and it starts even when hot and 3/4 thru season
 
Since it’s older I’m guessing it’s narrowband? I ran a similar gauge in my Miata when I went forced induction and it was helpful.
And as mentioned that "ideal" ratio is probably not ideal. One of my other cars is a Chevy 350 converted to TB EFI and I can read and alter the ratio in realtime, I learned quickly that 14.7 to 1 was not the way to go, from idle quality and up the rpm scale, let us know what you find once you can monitor.
 
I ran one before getting my Holley Sniper EFI. Find a good spot close to the collector and accessible to mount the O2 sensor. The sensor in the exhaust needs to point down a bit.

The readings are very helpful to dial in the carb, but remember it will only be reading one bank of cylinders.
 
Kern Dog said:
I have one. It is quite the eye opener how an engine swings wildly from rich to lean just during regular operation.
I installed mine over 10 years ago to help me with a detonation problem that I was dealing with. One thing that I learned the last couple years is that the goal of 14.7 ratio is based on 100% pure gasoline but when you only have ethanol gas to use, the numbers change. We have "up to 10% ethanol" here as stated on the gas pumps so if the ethanol levels are indeed 10%, the goal number changes to around 13.8 to 1.
Click to expand...
14.15
 
I run two of those gauges and they work very well.
As earlier said in this thread, check the plugs and also "feel" where the car is happiest/runs smooth.

I run 98 gas and my car likes 13.5 - 13.8 Afr best.
 
Well, keep in mind that your "98" is at a different method of rating the octane.
 
No, from the country that has been to the moon.

01 A1.jpg
 
Last edited:
Come on, man....If each of us didn't have pride in our home country, that would be a bad thing!
 
Well, right now EU/Sweden really sucks cos of all ill will against classics.
One example is the ELV (End of Life Vehicle) act that EU is proposing.

Back on topic:
I put two of those gauges in a stand alone housing with long cables to dual Bosch Afr sensors.
Then did a quick connect behind the fuse-box.
Installs in 10 minutes and easy to remove when done tuning the carb.
 
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