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What could cause a rich mixture?

When my car is idling it smells rich, and my air fuel gauge reads a little into the rich area. When im on the gas full throttle the air/fuel gauge reads the first bar rich and as RPM's increase, it gets richer and richer until it hits the last bar in the rich! This is safer than lean, but if i could get a little better fuel economy id like to fix it, thanks

John
Old 03-31-2003, 05:40 PM
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are you talking about the lil gauge on the bottom right of the dash? Because if that's the one you're looking at it's an oil pressure gauge and that's what it's supposed to do.
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Old 03-31-2003, 05:42 PM
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Is the car stock? What kind of air/fuel gauge do you have?
Old 03-31-2003, 05:43 PM
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Replace the O2 sensor
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Old 03-31-2003, 07:59 PM
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Gearhead:
No **** i know what all of the gauges are on the stock cluster!
Its an aftermarket air fuel gauge, a sunpro brand. It was cheap, but its no lying because it really smells rich when its idleing, and the gauge shows its a little rich.

I looked at the O2 sensor and it looks very new, no junk built up on it, still shiny and clean wires. How often shoudl these be replaced? I dont want to because they are damn expensive!

John
Old 04-01-2003, 08:04 PM
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When my car is at idle, it does that, it goes from the bottom up to a little rich, back and forth pretty fast, when im on full throttle it stays put(doesnt bounce back and forth) and climbs richer and richer as RPM's increase. I think it is all hooked up right.
Thanks

John

PS - is there anything you can "adjust" to change the air fuel mixture or is that the dme? Thanks
Old 04-02-2003, 08:43 AM
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You can adjust, in fact at our altitude you almost have to. There is a way........
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Old 04-02-2003, 09:06 AM
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Hey scott, You shall show me the way?!?!
Old 04-02-2003, 06:58 PM
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Old 04-02-2003, 06:59 PM
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Ok, here is the method.....

This first picture is of the inside of the AFM, you will see that the aramture sits all the way to the left when the engine is not running:



This second picture is about the position that it sits in when it's running, mark this position for reference: (sorry the pictures are not great, I was in a hurry and forgot to select macro.)




Now the BIG Black dial controls the default position of the arm, looking from the front rotate the dial a click or two counter clockwise until you loose the rich smell. The local P-car dealer charged me $50.00 to do this, then told me how it was done. Since I am chipped and modified this is the only way that I can get my rich condition to go away at our altitude.

Also note that you will need to adjust the idle after you adjust the AFM. And BTW the black plastic cap is held in place by silicon only, just pry it open.
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Old 04-02-2003, 07:23 PM
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O2 sensor is replaced every 30k I think but I am not sure. You can use the universal Bosch sensor and save alot of money. Its about $30 and available at any auto parts store.
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Old 04-03-2003, 05:36 AM
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I think you rotate clockwise to lean...That tightens the spring.
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Old 04-04-2003, 02:15 AM
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Clockwise to richen the mixture.
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81 924 N/A

Some people are like Slinkies. Not really good for anything, but you
still can't help but smile when you see one tumble down the stairs.
Old 04-04-2003, 05:24 AM
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I dont reall understand what to turn or what to look at that says where it is at when off and running but when i get in there i will understand it better. So in "theory" I could turn it in to richen up the mixture a little more when i supercharge it right? I know this wouldnt increase as boost does but it would still richen it a little. When you do turn it in, does that richen up the mixture completely, all the way through the RPM range and diddo when leaning it out? I will have to give it a shot, thanks scott!

John
Old 04-04-2003, 10:23 PM
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I just did this yesterday...and verified the results with my AFM, you rotate the ring clockwise to lean. That tightens the spring and causes the arm to rotate Less for a given air flow, thus resulting in less fuel.
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Old 04-05-2003, 03:19 AM
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Actually I found this becuase my supercharged 944 would not pass. So thats exactly what I needed to do get my SC through.
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Old 04-05-2003, 09:57 AM
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So to get it to pass you leaned out the mixture? Or you had to richen it up? If i did richen it for a supercharger then it would be rich in vacuum and be very smelly huh?

Thanks
Old 04-05-2003, 06:57 PM
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Nope, had to lean it out. Still didin't pass even after that. I had to eventually remove it then smog it again to get a sticker.

Envirotest is very strict, I don't know about Loveland, but if you have to dyno test like Denver teh you might have problems.

Didn't really matter, it only took about 4 hours total to remove and re-install.
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Old 04-06-2003, 08:36 AM
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