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1291 Views 7 Replies 5 Participants Last post by  DoodieHead
This past weekend I had the pleasure of installing Autometers' A/F Ratio Gauge. After the install when I first popped my car off my mixture was Stoich and then about 1 minute after the car was on it moved all the way to the last led light on rich. ??? I have heard that Subys' run really rich, but I didn't think it was going to give me a reading like that. My question is, is there any way to lean it out without getting a S-AFC or any other means of ECU tuning?? Any feedback is appriciated.:)
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S-AFC won't even be a permanent fix for the 00-01 RS's, as thier ECU will eventually learn around it and run it rich even when you set the S-AFC to full lean. Maybe the proECM that Larry sells fixes that, I'm not sure.
Either increase the air, or decrease the fuel. Without a S-AFC, you can lower your fuel pressure...that's right...LOWER your fuel pressure. The system will (logically) spray less fuel for a given pulse width.

...flame suit on...
did you install a separate o2 sensor?

if not, then your readings may be consider inacurate due to the stock o2 sensor's on a RS being of a broadband sort.
If you hooked it to the stock front (upstream) O2 sensor, it is going to read very high, because the stock sensor is a wide band, meaning it's voltage range is more that 0-1 volt, which is what the Autometer gauge is designed for. IIRC the stock sensor's range is 0-5 volts.

You can hook it to the stock narrow band downstream (rear) sensor, but the reading will be affected by the cat and not truely accurate.

The best solution is to have the local muffler shop weld in an O2 sensor bung somewhere near the stock upstream sensor, and run a dedicated narrow band sensor for the gauge. Any $20 Autozone single wire sensor will do fine, or spring for the heated variety ($50-100) and it will start respnding faster after startup.
Actually I already have the ProECM chip in my car, and I dont have any cats in my car. So what you are suggesting is hooking it up to the rear one. Get back to me. Thanks.:)
Actually I retract part of my previous statement. I just looked at the ECU wiring diagram and remembered that I hooked it up to B136;#18, which is the rear sensor. Any other suggestions?? I am soon going to be shipping my ECU off to Toronto for some tuning, so hopefully after that is done, it will lean it out a little bit. Also at the same time as the ECU tuning I am going to be getting some JA cams. I am guessing that my running rich problems will be solved here soon. Thanks for the info guys. :)
Direct Hits Helps!!

This weekend since it was nice out I thought I'd re-install my direct hits. I know what you are asking yourself, "Why did you take them out if they helped??" The reason that I had them out is because of all of the precepitation we have been having in Montana. Since the wires that come with the direct hits do not work correctly (soon to be fixed), you have to use the stock boots and they stick out of the cylinders about 2 1/2 inches which will allow moisture access to the inner block. Now that it is nice out I put them back in. Yee haa. My A/F ratio went down about 4-5 led lights closer to Stoich. Car is running so much better. Feel the pull baby!! :) Thanks again Shawn.

I recommend the Direct Hits, they are the best!!
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