2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

My A/F guage is wacky

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Old Apr 16, 2002 | 03:26 PM
  #1  
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From: mass
My A/F guage is wacky

I just hooked up my Haltuner and at idle it pins to full rich. Under hard acceleration it will move from rich to full lean with about half the LED's lit up. Im thinking I have it hooked up wrong. What did you guys use for power source, ground, and dimmer to hook up your A/F guage?

Oh and the Haltuner comes with its own O2 sensor so I dont think thats the problem. Im guessing its in the wiring but then again, I have no clue.
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Old Apr 16, 2002 | 11:03 PM
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From: Greenville SC
power= 5amp fuse
ground= frame
dimmer=o2 ssensor
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Old Apr 17, 2002 | 12:20 AM
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Yep... sounds right
How much boost are your running?
It'll always read full rich at idle, (it's not in closed loop- dumb Mazda) and with your mods, you may be leaning out considerably up high!
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Old Apr 17, 2002 | 02:05 AM
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From: Katy Tx. 77084
Where do i hook up the power? do i need a 5v fuse for mine to work? is that y it wont work? i have it wired up to the 02 sensor wire. and when i go to hook it up to power and ground nothing comes on....

can i just wrap it around a fuse or should i make an inline fuse and run it to a ingition source, and should i wire the sensor wire to the o2 or to the ecu?

btw i have the autometer a/f guage....

thanks
rocky
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Old Apr 17, 2002 | 04:42 AM
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From: mass
Im boostin at 10 right now but the kid I got the car from said it read a little rich under boost. When I got the car it wasnt hooked up becuase he was going to make a custom mount. So the haltuner comes with its own O2 sensor which means Im running without one. I dont have an O2 sensor, just the one supplied with the guage and its not feeding anything to my ECU, it just feeds the guage. Now I have my ground all set but Im running my switched 12v+ and dimmer off the cigarette lighter wires. Everything there sound alright?
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Old Apr 17, 2002 | 07:22 AM
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Why would the a/f read full rich at idle? can someone tell me? mine reads 5-6 bars and flickers up and down - I know thats normaly OK but I guess my air pump could conflict the situation??? Its still hooked up.
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Old Apr 17, 2002 | 07:49 AM
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Saabguy.......I think your car is not working right. At idle, the PORT AIR feature of the acv should be dumping fresh air from the air pump into the intake manifold, prior to the 02 sensor, causing a lean reading on the meter. Its possible that your SWITCHING solenoid is not working or the vac hose for it on the acv is not putting a vacuum on the acv. See the attached diagram where the switching solenoid should be pulling a vac on that diaphram which in turn pulls the poppet valve out of the way and lets air go into the PORT AIR passage to the intake manifold. That is the air that causes the reading to go to a minus number on the meter. I can make the reading read lean or rich on my car just by pulling the switching vac tube on and off the acv. That action opens and shuts the air to the PORT AIR. If I use a volt meter on the 02 gauge I see a minus figure with the acv working right. With the switching solenoid or vac tube disabled I read something like .7 volts at idle. EDIT, EDIT: Saabguy, I just realized what is wrong with your car. Its a turbo and the switching diaphram is cooked in the acv. Take a piece of vac hose and put it on the nipple that sticks straight up on the acv. Suck on it and if it does not hold a vacuum, its toast, which in turn means the PORT AIR never gets ported. Makes emissions just a little tougher to pass and gives high 02 readings at idle.

Last edited by HAILERS; Apr 17, 2002 at 08:05 AM.
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Old Apr 17, 2002 | 07:55 AM
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Mine stays at the 2nd from last yellow at idle. I know the car is running richer than that, I can smell it. I suppose I need to change O2 sensors, I haven't done that yet.
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Old Apr 17, 2002 | 11:50 AM
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thats odd. my car passed emissions with flying colors. Am I damaging anything?? hmm..... maybe THATS why my vac at idle floats from 16 to 18!!!!!!!!!!
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Old Apr 17, 2002 | 12:00 PM
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Didn't mean to imply that emissions can't be passed. If you can put a vac hose on that nipple that sticks straight up on the acv, and not be able to hold a vac when you suck on it, well that constitutes a vac leak and could very well cause a vac gauge to vary up and down. I had to take Six Rotors advice and salvage the switching diaphram out of an old 82 acv to make my turbo ii acv work. Minor metal work involved there. Far as I'm concerned you are not harming anything, but if you don't pass emissions some year, take a look at it. If the diaphram is leaking, I'd just plug the vac hose going to it to prevent the *vac leak*.
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Old Apr 17, 2002 | 12:11 PM
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Felix Wankel, I doubt there is anything wrong with the 02 sensor, but I doubt that your acv is working right. I've got three of these pigs, and one thing I have learned from them, is that if the acv is working at idle, and is sending PORT AIR to the exaust ports(darn I just realized I made a mistatement in an earlier post where I used the words *intake manifold* when I shoulda said exaust ports), then the 02 sensor will read very low, down in the minus figures. If the acv does not send the air to the exaust ports, then the 02 sensor will read in the .7 or so range. Rx run rich at idle. Normal. But usually is masked by the port air being mixed prior to the 02 sensor.
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Old Apr 17, 2002 | 01:25 PM
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Would you reccommend I remove my airpump belt when I tune my SAFC? If I ever get the darn thing in the mail.
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Old Apr 17, 2002 | 10:59 PM
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Originally posted by HAILERS
Felix Wankel, I doubt there is anything wrong with the 02 sensor, but I doubt that your acv is working right. I've got three of these pigs, and one thing I have learned from them, is that if the acv is working at idle, and is sending PORT AIR to the exaust ports(darn I just realized I made a mistatement in an earlier post where I used the words *intake manifold* when I shoulda said exaust ports), then the 02 sensor will read very low, down in the minus figures. If the acv does not send the air to the exaust ports, then the 02 sensor will read in the .7 or so range. Rx run rich at idle. Normal. But usually is masked by the port air being mixed prior to the 02 sensor.
What ACV?

My car is minus the ACV, BAC, EGR, air pump, solenoid rack, etc.
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Old Apr 21, 2002 | 08:56 PM
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Hey, i hooked up an A/f guage to a 1 wire ox sensor and it seems to work fine and stuff but doesnt read crap at idle is that good or bad and it wolnt go all the way to rich when i punch it is that good ? I dunno i'm just gettin used to all this rotary bits and peices.. HELP !
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Old Apr 21, 2002 | 11:40 PM
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what is the ACV any way ? I think that may be my prob.. it's not seemingly running "Rich" it's like -neg. figures..hahah
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Old Apr 22, 2002 | 07:45 AM
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SOULPYRO......Your car is normal in that your acv is working as it was designed. At idle the acv is mixing air from the airpump into the exaust ports right at the exaust manifold, and just prior to the 02 sensor. Thats why you see a negative figure. You can disable this feature of the acv a couple of ways. One thing is to remove the BLUE connector from the relief solenoid on the drivers side of the engine. Another is , if you have a 86-88 car, remove at least one of the two bullet connectors on the bottom of the radiator. A third is to remove the airpump belt. Any of these should disable the air flowing thru the acv to the PORT AIR. The 02 sensor should then show a figure of being rich, like .7 volts.
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Old Apr 23, 2002 | 08:00 AM
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Would this make my car faster or slower by doing so, you've also made like 3 ways i can do this so, which would affect me more in power and what not..i mean the wire seems to be the easiest way to go about this but, i think the belt may make me faster.. no clue.. but, if i take the ACV out of my car what will it make it not do or do i want to save gas and stuff.... and is there like a how to on removing the wire ? I'm kinda dumb on how to EXACTLY go about doing so unless i'm shown...
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