air feul ratio gauge

[GOR33]

geez, thats might mean that sumthin is wrong with my guage or the way i hooked it up cuase its shown more thne 1 led at a time, and sumtimes it stops, then when u hit the accelerator it will work again???

[Craved]

sounds the same as mine, usaually have 3 leds lit up.. when you are at constant throttle it'll pulse from 1 red to the end of stoich. thats normal..

however read the manual, if its auto meter then the stich level is actually around 12:1 from memory, bit higher than is optimal!

[Sydneykid]

If the aftermarket gauge you have uses the standard lambda sensor, then there are a few things that you need to know first. The standard lambda sensor (in all cars not just Skylines) is what I call slow and narrow (S&N). They react slowly to changes in A/F ratios and only measure over a very narrow band of A/F ratios. So not only can the car go super lean very quickly and the read out not show it (the slow part), it can also be so lean that it is outside the measuring range (the narrow bit). On the dyno we use a fast and wide (F&W) lambda sensor, obviously this responds quickly to changes in the A/F ratio and it measures over a very wide range of A/F ratios. As usual, cost is the issue here, a F&W lambda sensor costs around 10 times as much as a S&W lambda sensor.

When you start your car up from cold it runs rich, so rich that the standard lambda sensor does not measure that much richness, the gauge (relying on the lambda sensor) will simply go full rich or look like nothing is happening. As the car warms up, obviously it no longer requires a rich mixture to run, so you will get some reaction from the gauge. But it will move around a lot, because it is only measuring over a very small range of A/F ratios, like 11.7, 11.8, 11.9 12.0 etc.

At light throttle cruise (no boost) you see lambdas around 14 or 15, some gauges have trouble showing this normal (lean) situation. A full throttle and climbing rpm, the lambda sensor will have big trouble keeping up with the changes, so treat the results with a lot of suspicion. At idle they normally work pretty well, as things happen slowly and the lambda is within their sensing range.

Bottom line, if you want a useable A/F ratio gauge you really need to start with a F&W lambda sensor and then buy a gauge that can read it.

Hope that helps