Help with New Air/Fuel Gauge Install.....No reading!?!?

atey950

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Aug 5, 1999

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Southeastern PA

Jan 27, 2004

#1

• Jan 27, 2004

• #1

I just replaced my old air fuel gauge with an autometer. All I did was remove the old one and splice in to the existing wires. When I start the car, there is 1 green light lit in the corner of the gauge, but it doesnt move at all. Now, the old one did this too, so I think it is safe to assume that the guage is not faulty. So what do I need to check. I guess one of these wires runs down and connects with the 02 sensor right?
Could it be anything else....?

 

whitehorseupnorth

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#2

• Jan 27, 2004

• #2

Well, first off did you let that car warm up? I assume you did. You will be in open loop for a while till the car warms up. I hooked mine into the signal wire at the O2 itself. Take the purple wire from the meter and splice it into the red wire going to the left side O2. If the O2 is bad this could cause your problem of only seeing the green lite up. Green is rich so make sure your car has a proper tune. Also they are useless on a car with a turbo or SC. Only reads 0V-1V. Hope this helps.

 

whitehorseupnorth

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#3

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• #3

Sorry, just read your sig. You have a SC, they are basically useless. Do yourself a favor and invest in a wideband O2. This will give you an accurate A/F ratio, like at a dyno. Heres one that looks decient. www.innovatemotorsports.com

 

atey950

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Jan 27, 2004

#4

• Jan 27, 2004

• #4

Well, I must be an idiot then.....

1) I did not let the car warm up beacuse it was late at night and my neighbors will call the cops......
2) I do have a blower. you are telling me it is pointless to have an A/F gauge with a blower? I didnt know that. Can you please explain to me why that is...?
I thought it would make sense to have one.

 

atey950

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#5

• Jan 27, 2004

• #5

nevermind....you replied while I was typing my post.
I'll check out the site. Thanks!

 

P

PRO50SC

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Jan 27, 2004

#6

• Jan 27, 2004

• #6

I have a blower on my 92 and my a/f gauge works no problem.

 

whitehorseupnorth

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#7

• Jan 27, 2004

• #7

Well it's not completely useless,but just about. That guage you have will only tell you rich or lean and doesn't have much of a range. If your A/F ratio is say 15, it will read lean or maybe of the scale. Same with being rich. They will work better for N/A because the A/F ratio doesn't change that much. In a boosted application the A/F ratio can go from 16.0 at idle to 11.0 or under during full boost. This range is out of the parameters that the gauge will read. So all you will get is one light on on either side, depending if your rich or lean. I take it you got it to keep an eye on things. Well that gauge is no good. You need a wideband O2 to really tell you how rich or lean you really are. I know this is confusing, sorry

 

S

sleeper89

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Jan 27, 2004

#8

• Jan 27, 2004

• #8

why is it that you say a/f guage won't work on a blower car? i mean, you want both n/a and blower cars to run around the 14.7:1 (albeit slightly richer for peace of mind) so it should work. can you please elaborate on this as i don't understand your reasoning. lets say 13:1 is .5v at the 02 sensor on a n/a car, should be the same on a blower car, no??

-steve


***nevermind, you beat me to the post.***

 

whitehorseupnorth

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#9

• Jan 27, 2004

• #9

sleeper89 said:

why is it that you say a/f guage won't work on a blower car? i mean, you want both n/a and blower cars to run around the 14.7:1 (albeit slightly richer for peace of mind) so it should work. can you please elaborate on this as i don't understand your reasoning. lets say 13:1 is .5v at the 02 sensor on a n/a car, should be the same on a blower car, no??

-steve

Click to expand...

Ya, it will work. But the range that the autometer guage is narrow. For his application you really should have a wideband O2, if you are interested in monitoring the A/F ratio. How are you going to know how rich or lean you are? For anything under boost I feel it's not usefull. I would want an accurate number myself. If you are running 16-17 A/F (which I have seen) how would know on that guage? Only that it doesn't register. Thats no good. For N/A vehicles, I feel it is a little more practical. Heres something I found that explains how the autometer works. www.rx7turboturbo.com/robrobinette/autometer_af.htm

 

S

sleeper89

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#10

• Jan 27, 2004

• #10

cool man, thanks. i've never dealt with those a/f gauges so i did not know. FWIW i would get the wideband even in n/a applications given the info you just provided.

-steve