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A/F Mixture changes when head lights on


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11 replies to this topic

#1 Marck

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Posted 02 January 2006 - 03:12 PM

I have one of those Autometer A/F Mixture gauges. When I turn on the head lights, the gauge shows that the mixture runs leaner by about three more bars. Then if I turn on my fog lights, it will run a little leaner. I don't think the gauge is reading wrong because I also notice that the idle speed drops a little too.

Do you think my gauge is faulty or is there something I can do or adjust to fix this?

#2 Hodaka Rider

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Posted 02 January 2006 - 03:21 PM

Have you upgraded all your ground wires, and made sure they're getting a really good connection? Some people have even added extra grounds to good effect. This is actually a fairly common fix to fuel injection / ignition problems.

#3 Frank B

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Posted 02 January 2006 - 06:39 PM

10 guage wire connected to the engine block to the body works well. Also check your alternator.

#4 4WDFrenzy

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Posted 02 January 2006 - 08:50 PM

I have one of those Autometer A/F Mixture gauges. When I turn on the head lights, the gauge shows that the mixture runs leaner by about three more bars. Then if I turn on my fog lights, it will run a little leaner. I don't think the gauge is reading wrong because I also notice that the idle speed drops a little too.

Do you think my gauge is faulty or is there something I can do or adjust to fix this?


I had something similar happen on my GL-10. If you are running your A/F gauge with the factory O2 sensor, it will do it. It won't hurt anything. After a couple seconds, the LEDs should start going back and forth. If you're running a wideband, I couldn't tell you off hand what the deal is.

Patrick

#5 Marck

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Posted 02 January 2006 - 09:33 PM

I had something similar happen on my GL-10. If you are running your A/F gauge with the factory O2 sensor, it will do it. It won't hurt anything. After a couple seconds, the LEDs should start going back and forth. If you're running a wideband, I couldn't tell you off hand what the deal is.

Patrick


I am running it off the factory O2. So this is normal then. So is the engine actually running leaner as the gauge suggest when the head lights are on or is just error due to reading off the factory O2.

Should turning on the head lights cause the idle to drop a little? Do you think adjusting the screw on the fast idle solenoid will do anything?

#6 WJM

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Posted 02 January 2006 - 11:11 PM

Thats normal...JWX has the same setup. Those narrow band gauges are junk. Seriously. I'm not knocking your stuff, but they are worthless.

#7 soobscript

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Posted 03 January 2006 - 06:04 AM

My idle drops a little with lights and other electrical stuff turned on.

#8 4WDFrenzy

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Posted 03 January 2006 - 07:14 AM

I am running it off the factory O2. So this is normal then. So is the engine actually running leaner as the gauge suggest when the head lights are on or is just error due to reading off the factory O2.

Should turning on the head lights cause the idle to drop a little? Do you think adjusting the screw on the fast idle solenoid will do anything?


I'll put it to you this way, A/F gauges aren't accurate when running off a factory O2 sensor. They will give you a rough idea of how rich or lean the mixture is, but they aren't exact. It is normal for the idle to drop as more electrical accessories are turned on.

You can adjust the fast idle screw and increase the idle RPMs. Mine is running about 1000 RPMs at idle, but the idle still drops a bit after I turn on headlights or other accessories. The gauge will still read that the idle mixture is leaning a bit, but it isn't leaning out as bad as it seems by looking at the gauge.

Patrick

#9 Marck

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Posted 03 January 2006 - 10:47 PM

Alright, thanks for the replies. When the head lights are on and the turn signal is on, the A/F Mix gauge goes back and forth in sync with the turn signal. It kind of reminds me of Christmas :rolleyes: .

Although it is not even close to the accuracy of a wideband, I think it is well enough to keep me from leaning out when I increase the boost. Widebands are way to expensive for my blood.

#10 D-Cal

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Posted 03 January 2006 - 11:00 PM

Make sure you run a dedicated ground for the gauge back to the negative post of the battery. Tying it in somewhere else will often give you an inaccurate reading. The sensor voltage is in the range 0-1v, so changes as small as 0.1v will be seen on the gauge as two lights.

#11 Myxalplyx

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Posted 04 January 2006 - 07:24 PM

Although it is not even close to the accuracy of a wideband, I think it is well enough to keep me from leaning out when I increase the boost. Widebands are way to expensive for my blood.


I know what you mean. You can use your gauge to good affect though. With turbocharged cars running in the richer a/f ratio range than N/A cars (especially with modifications done the the turbocharged car), then the inaccuracies start to show its ugly face. Nice to see you even have one in the first place. I need one myself but I'm still stuck on the Jumptronix digital models. I would get an EGT gauge before getting an a/f ratio gauge though.

#12 WJM

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Posted 04 January 2006 - 07:50 PM

Make sure you run a dedicated ground for the gauge back to the negative post of the battery. Tying it in somewhere else will often give you an inaccurate reading. The sensor voltage is in the range 0-1v, so changes as small as 0.1v will be seen on the gauge as two lights.


That reminds me that I need to put my ground where it *SHOULD* be when the new sensor gets here tomorrow.




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