wideband numbers

[svtdvm]

My AEM wideband reading fluctuates a lot between low 15's and low 16's at idle and mid 14's to high 15's at cruising speeds. At WOT it starts around mid 11's and drops to mid 10's. I know the WOT 3rd gear reading is what’s most important and that I’m running rich there, but I am concerned about my idle and cruising a/f ratios. Shouldn’t they be about 14.7 with very little fluctuation? What could be causing these fluctuating readings and is my gauge accurate?

btw - The sensor is mounted drivers side before the cats, just before the stock sensor.

 

[Fade 2 Black]

Are you the same guy over on NLOC with this issue? If not then it's a common thing for AEM's to do or there are some bad ones out there.

You are correct at cruise you should be a steady 14.64 and under open loop should read whatever your tune is. At idle it will flux some due to the pcm constantly adjusting the mix to maintain idle speed.

 

[svtdvm]

No, that's not me but I did see that thread. His issue was at WOT.

 

[boca ron]

its digital it rarely settles to a hault always blips up down not like a needle gauge. NORMAL

 

[rlearp]

I've got my AEM on now. At cruise, just going down the highway, it is pretty steady at 14.7 to 14.8. Doesn't move around.

Now, at WOT is drops into the 10-11 range, naturally moves quickly to get there, but if held at WOT stays pretty steady at 11-11.5 depending on RPM at WOT. Probably as lean as I'd like to see it since I'm not going for huge numbers, but safe driving.

I'll watch it at idle and let you know what mine does there.

Ron

 

[Fade 2 Black]

That's what it should do, digital or not.

 

[boca ron]

as long as the o2s switch over the tune is pcm is constantly adjusting for a number of variables sensors, load, temp, etc.......... after alot of installs I see the aem seldom stay settled for long, fuel trims are constantly on the move as well, datalog and you will see. these functions will have a reactive effect on the aem, very accurate guage that is sencitive to the slightest of change it will tell you that by moving constantly. Read theliterature that came with it so you dont have to believe anyone less than accurate as previously mentioned.

 

[Fade 2 Black]

Good advice boca, that last thing I'd ever want to do is be thought a liar.

 

[svtdvm]

Well, which ever the case may be, the question now is why does my gauge fluctuate one full point at cruising speeds while rlearp's stays steady at 14.7 - 14.8? Are both of our gauges dead on and it's just that my truck's a/f truly fluctuates that much and his doesn't?

 

[Fade 2 Black]

I think it's your gauge but what the hell do I know.

Best off to call AEM and see what they say. Good luck with it.

 

[rlearp]

Well, which ever the case may be, the question now is why does my gauge fluctuate one full point at cruising speeds while rlearp's stays steady at 14.7 - 14.8? Are both of our gauges dead on and it's just that my truck's a/f truly fluctuates that much and his doesn't?

I don't know, but I'd call them and check those grounds - my money is on a ground problem.

Mine is definitely moving at cruise, but it is moving to like 14.7, 14.8, 14.7, etc. - back and forth about a tenth of a point. If I move the throttle it'll instantly move richer while it transistions and everything catches up.

Based on my dyno runs, and assume the dyno wideband is accurate, I'd say the gauge is pretty darn accurate too since it matches pretty closely what I've seen on the dyno. Might show a little richer than the dyno, at least based on my data. But, I think it is definitely accurate enough to tune off of and I know my truck is richly safe!

R

 

[boca ron]

page 9 on outputs aem manual example= a true 12.00 AFR has led or digital readout range of 11.875 to 12.125 another a true 11.50 AFR range = 11.375 to 11.625 a true 11.875 range = 12.00 to 12.125 hope this helps the AEM is hunting if you will in a narrow range seldom still

 

[svtdvm]

page 9 on outputs aem manual example= a true 12.00 AFR has led or digital readout range of 11.875 to 12.125 another a true 11.50 AFR range = 11.375 to 11.625 a true 11.875 range = 12.00 to 12.125 hope this helps the AEM is hunting if you will in a narrow range seldom still

Ron - If mine fluctuated constantly, only 0.3, like these examples show, I wouldn't be concerned at all. Mine varies from 0.75 to 1.5. This doesn't seem right. I will double check with AEM on Monday and see if they think it's normal, bad ground, exhaust leak around bung, or whatever. Thanks for the input. All opinions are welcome.

 

[boca ron]

Im local, is the bung pre or post cats or do you have cats

 

[svtdvm]

Im local, is the bung pre or post cats or do you have cats

The bung is mounted drivers side before the cats, just before the stock sensor.