a/f gauge misreading?
07-21-2003, 10:01 AM
#1
Three Wheelin'
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a/f gauge misreading?
My A/F gauge has recently started to appear as if my car is running leaner than it was a week ago, however this seems to come and go. When I start the car it now idles on lean occassionaly, when it used to idle more on stoich. When I am cruising at around 2000-3000 rpm it goes stoich-lean, stoich-lean, stoich-lean...as it used to. However, it does not go as far into stoich as it usually does either. Then, under boost, the car will go full stoich and into rich, but not as far into rich as it had a week ago, and it appears to flicker a lot, as if it notices the normal signal, but the connection is weak or something.
I have checked all of the connections I can easily see, however I am not sure where the o2 sensor is exactly, as I definately want to check this.
Any advice would be great. Thanks.
I have checked all of the connections I can easily see, however I am not sure where the o2 sensor is exactly, as I definately want to check this.
Any advice would be great. Thanks.
07-21-2003, 10:44 AM
#2
Race Car
This is very similar to what's happening on my car. If you get a chance to check the O2 sensor before I do, let me know what you think. I'm worried I may have an injector going bad or a weak fuel pressure regulator.
What lambda sensor do you have?
What lambda sensor do you have?
07-21-2003, 11:17 AM
#3
Three Wheelin'
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I am thinking one of my injectors is going as well, although I have not had a chance to get over to the car today. I will let you know what I find out when I check it out.
07-21-2003, 11:55 AM
#4
Race Director
The O2-sensor is going bad. It outputs a lower and lower voltage for the same air-fuel ratios. So instead of going from 0-1v, it goes from 0-0.8v or 0-0.6v and ends up showing lean on your gauge.
07-24-2003, 09:26 PM
#5
Three Wheelin'
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A Porsche mechanic did a test on the O2-sensor today and said it seemed to output the correct voltage. Could something else be wrong with the O2-sensor? If not, what else could cause my gauge to do this?
07-24-2003, 09:39 PM
#6
Race Director
Check your power lines and grounds going to the gauge. These analog voltage-comparator devices uses a reference voltage and compares that to the O2-sensor voltage and determines which LED to light. But if the reference-voltage is not correct, it'll throw off the display. You may have noticed the LEDs shifting a little if you put your high-beams on or hold your finger on the window-button after it's fully closed? Could be your voltage-regulator is losing voltage perhaps? Or just the power and ground lines on the gauge may have gotten tweaked somehow...
