"erratic" A/F reading
06-18-2010, 12:19 AM
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"erratic" A/F reading
Recently installed my brand new AEM UEGO wideband gauge and I'm having issues with readings at idle.
While at a standstill (foot off gas), my gauge will read normally (14.4-14.8) and every 10-15 seconds my gauge will peg fully lean real fast. I've tested my O2 sensor (brand new) according to AEM's recommendations- passed with flying colors, checked for exhaust leaks- passed (according to exhaust guy leak testing it), ran good fuel injector cleaner to help- runs great except for what seems like a slight misfire? at times (runs much better than most cars I drive), checked condition and regapped plugs, blah blah blah all that good **** lol. I'm not blaming this "misfire" for my possible lean reading, but I'm definitely not looking past it. Not super worried about that part yet...
What I need to know is, is/has anyone else having/had a similar issue? I'm not expecting anyone to fix my issue as that's my problem, but I'm curious to see if maybe I'm overlooking something, or if this is common with AEM gauges. I'm grateful for any help. One thing that did strike me as odd was my wb sensor bung placement. I had already paid for the job and left it at the shop so I could go to work. After picking it up, I noticed he welded my bung on the tapered section of the catalytic converter (pre honeycomb) and I thought maybe turbulence was screwing with my reading. The sensor tip does not touch the honeycomb section and the readings the rest of the time seem perfect!
I'm going to scan it tomorrow to see if it's actually a misfire that I'm feeling and which cylinder it's coming from.
Any input is helpful!
perf. mods- stage 2, custom tune, Pacesetter header, AEM airbox mod. I use 1 step colder NGK plugs @ 0.035"
While at a standstill (foot off gas), my gauge will read normally (14.4-14.8) and every 10-15 seconds my gauge will peg fully lean real fast. I've tested my O2 sensor (brand new) according to AEM's recommendations- passed with flying colors, checked for exhaust leaks- passed (according to exhaust guy leak testing it), ran good fuel injector cleaner to help- runs great except for what seems like a slight misfire? at times (runs much better than most cars I drive), checked condition and regapped plugs, blah blah blah all that good **** lol. I'm not blaming this "misfire" for my possible lean reading, but I'm definitely not looking past it. Not super worried about that part yet...
What I need to know is, is/has anyone else having/had a similar issue? I'm not expecting anyone to fix my issue as that's my problem, but I'm curious to see if maybe I'm overlooking something, or if this is common with AEM gauges. I'm grateful for any help. One thing that did strike me as odd was my wb sensor bung placement. I had already paid for the job and left it at the shop so I could go to work. After picking it up, I noticed he welded my bung on the tapered section of the catalytic converter (pre honeycomb) and I thought maybe turbulence was screwing with my reading. The sensor tip does not touch the honeycomb section and the readings the rest of the time seem perfect!
I'm going to scan it tomorrow to see if it's actually a misfire that I'm feeling and which cylinder it's coming from.
Any input is helpful!
perf. mods- stage 2, custom tune, Pacesetter header, AEM airbox mod. I use 1 step colder NGK plugs @ 0.035"
06-18-2010, 02:19 AM
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Mine does this same thing. I never really thought much of it cuz it's not a constant all the time thing. But I've seen mine bounce between 14.4-15.2 and then all of a sudden it'll just go --- and bounce back to the 14's. Car doesn't stumble (at least not that I can notice) and nothing else seems to be off. It's probably just the way the car runs would be my guess?
06-18-2010, 02:28 AM
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I wired mine up straight to the boost gauge wiring harness so it's on all the time only when the car is. I know my connections are good, so I doubt that would be your problem. Mines gone dead lean for like 15 seconds before and I had my hand on the key ready to shut her down when it bounced down to an 11.x and then back up to normal stuff lol I think it just has something to do with the way the tune is telling the injectors to fire or something. Again...I always thought its normal, if it's not I suppose I need to get mine looked at too lol
06-18-2010, 02:41 AM
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Well, hopefully this thread will help us get some possible answers. I'm betting stumble or "miss" I'm feeling is just normal. It's just more noticeable with stiffer mounts and I'm not used to it. I drive different vehicles all day long and they actually seem to idle worse than my car. New GM cars/trucks. I'm just picky as hell and I'm known to be a perfectionist when it comes to anything. Nothing is right in my mind. Damn OCD.
I'll play around with the scanner tomorrow. I just need to stop being so lazy. lol Creating threads give me that extra push.
I'll play around with the scanner tomorrow. I just need to stop being so lazy. lol Creating threads give me that extra push.
06-18-2010, 02:45 AM
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The local dealer I used to take my car to said the same thing about me lol I took it in there because there was an almost inaudible "clunk" noise that their techs swore up and down they couldn't hear...so I said "just put it on the lift and check the suspension and steering ****, something isn't right up there". Sure as ****, bad swaybar endlink and steering column 
They then said, it wasn't even that bad, we have no idea how you heard that. I was like, because it's MY car that I drive everyday and when something like that pops up, you notice it. They too told me once that I'm way too picky....and I said I didn't think it was being picky that these problems arose on a car that had only been driven for 12 months and only had 8k miles on it....
They then said, it wasn't even that bad, we have no idea how you heard that. I was like, because it's MY car that I drive everyday and when something like that pops up, you notice it. They too told me once that I'm way too picky....and I said I didn't think it was being picky that these problems arose on a car that had only been driven for 12 months and only had 8k miles on it....
06-18-2010, 09:00 PM
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lol it's not going lean for 15 seconds....just every 10 seconds or so it will peg real fast and then return to normal for another 10 seconds or so
got slammed at work and didn't have the opportunity to check anything
got slammed at work and didn't have the opportunity to check anything
06-19-2010, 12:59 AM
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to be honest it's normal... if it hits 14.79 AFR it will peg full lean... and alot of cars even mine would jump to 15.1 or so at idle from time to time...
Its normal don't freak out... worry about WOT LOL anywhere between 14.6 and 15.0 is pretty normal
Its normal don't freak out... worry about WOT LOL anywhere between 14.6 and 15.0 is pretty normal
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