Kev.O Posted May 8, 2013 Share Posted May 8, 2013 (edited) After the winter storage I have finally got round to sorting the car out ready for Japfest. Only issue is my UEGO is showing lean (17) on idle though when I connect the AEM software the O2#1 is showing 7 and in some cases lower. There is a real smell of fuel! Which reading should I pay attention to in order to try and work out what is happening? Any help will be gratefully appreciated. I have a video that I can email someone if need be. Thanks in advance. Kev Edited May 8, 2014 by Kev.O (see edit history) Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 9, 2013 Share Posted May 9, 2013 i would take it to a tuning garrage and let them plug a calibrated one in the exhaust then you will know , or buy and new wide band Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 i would take it to a tuning garrage and let them plug a calibrated one in the exhaust then you will know , or buy and new wide band I was hoping to be able ot have a look at diagnosing the issue before driving the car. If I can work out which reading I should pay attention to, I will have a better chance of fault finding. I am going to go over the obvious things tonight. When I last used the car, everything was fine, so I don't think it's anything major IMO. Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 9, 2013 Share Posted May 9, 2013 how does the car run ? could be just a duff sensor or both if you have a stock o2 sensor unplug it and the car will go rich as default which will be safe to drive to the nearest garrage , that being said you could always check the voltage at the pin and check the o2 signal to make sure its between 04 and 0.7 I think thats the right voltage double check for the thread as i cant remember the pins to check Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 The car runs a 'lumpy' on idle, though when I did move it, it drives ok just seems to be an idle issue. I will look at the Idle stpper motor tonight, I'm just confused as to why I am getting two totally different readings. I'm pretty sure I removed the stock O2 sensors (carried out the single conversation several years ago and without checking I can't be 100% certain). Thanks for your input Mellonman! Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 9, 2013 Share Posted May 9, 2013 sorry what is your can spec ? AEM ECU? this might help not sure http://www.mkiv.co.uk/vbb/showthread.php?35940-Narrowband-O2-Sensor&highlight=sensor Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 9, 2013 Share Posted May 9, 2013 did you have the battery disonected and do you have a piggy back ecu , it could be just the stock ecu reseting and correcting fuel trims ? but you do need to fine out what afr is correct thats for sure - - - Updated - - - did you have the battery disonected and do you have a piggy back ecu , it could be just the stock ecu reseting and correcting fuel trims ? but you do need to fine out what afr is correct thats for sure Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Here is the spec: linky. I have a stand alone AEM ECU wth an AEM UEGO wideband sensor. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2013 Share Posted May 9, 2013 Just a quick thought, the AEM has two O2 inputs, are you looking at the right one, sometimes the sensors were wired into O2#2 not 1. Worth a check Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 When I look at the table on the software (I'm no expert so only viewing it as opposed to altering things) there is only the one showing, which I can see alters as I blip the throttle. Does this prove I am looking at the correct input? Thanks for the help chaps, really appreciate it. Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 9, 2013 Share Posted May 9, 2013 as you see it change when you blip the throttle shows its connected , but is it that you just have the one wide band ? maybe take it out and check it http://www.youtube.com/watch?v=s3R8whD3ZWg Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 as you see it change when you blip the throttle shows its connected , but is it that you just have the one wide band ? maybe take it out and check it http://www.youtube.com/watch?v=s3R8whD3ZWg Yes I definetely only have the one wideband. I will have to try that as well. Looks like I could be busy tonight Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 9, 2013 Share Posted May 9, 2013 Could be that it needs recalibrating, other than that have you checked the std ECU water temp sensor? as this can have a large impact on low load fueling if its faulty. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Could be that it needs recalibrating, other than that have you checked the std ECU water temp sensor? as this can have a large impact on low load fueling if its faulty. I haven't managed to check anything yet if I'm honest. I started looking at possible faults when running rich, but I can't be certain it is actually running rich. I will check the water temp tonight. What I still can't get my head around is why would I receive two totally different readings from the same sensor! Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2013 Share Posted May 9, 2013 What I still can't get my head around is why would I receive two totally different readings from the same sensor! Calibration differences in the software displaying the result, if I remember correctly you can calibrate the gauge type sensors by ensuring a set output with the sensor disconnected, its been a while since I did any AEM work, might be worth checking the gauge manual. Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 9, 2013 Share Posted May 9, 2013 the answer could be staring you in the face Q: why would a sensor give out 2 different readings? A: sensor is faulty haha joking but could very well be true , the aem sensor is already calibrated so wouldnt be that , well doubtfull anyway Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Calibration differences in the software displaying the result, if I remember correctly you can calibrate the gauge type sensors by ensuring a set output with the sensor disconnected, its been a while since I did any AEM work, might be worth checking the gauge manual. So in you're opinion wes, should i believe the gauge or ECU read out? Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Here's a screen shot of the video I took. Although the idle is high in the video the revs are still lowering as I just blipped the throttle: Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2013 Share Posted May 9, 2013 Again its been a while, but is the AEM Power ECU software configured to display the correct O2 units? Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Again its been a while, but is the AEM Power ECU software configured to display the correct O2 units? I'll load up the software tonight and have a look. I can't be sure. Would a flat battery (from the winter) default settings by any chance? Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2013 Share Posted May 9, 2013 I'll load up the software tonight and have a look. I can't be sure. Would a flat battery (from the winter) default settings by any chance? It shouldnt do. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 9, 2013 Share Posted May 9, 2013 Is that o2 reading in AFR or volts? as said calibration differences could also be a problem, i and not sure if the AEM ECU has its own wide-band controller or does it rely on a separate one?, as Wez said it could be down to the output calibration, if its a separate unit, o2 calibration does go out, but does the controller recalibrate itself on every start, i haven't used the AEM stuff, just Innovate which needs periodic recalibration to get the best from it, not keen on the idea that the sensor needs no recalibration, as the sensors output can change over time. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2013 Share Posted May 9, 2013 Is that o2 reading in AFR or volts? as said calibration differences could also be a problem, i and not sure if the AEM ECU has its own wide-band controller or does it rely on a separate one?, as Wez said it could be down to the output calibration, if its a separate unit, o2 calibration does go out, but does the controller recalibrate itself on every start, i haven't used the AEM stuff, just Innovate which needs periodic recalibration to get the best from it, not keen on the idea that the sensor needs no recalibration, as the sensors output can change over time. The AEM AFR gauge outputs 0-5v signal to the ECU, the ECU has a calibration which can be modified, the gauge output itself is none configurable I believe. The older AEM ECUs do not have any UEGO controller built in, in fact before the gauge type came out there were single and dual UEGO controllers which had a separate box which again fed the ECU a 0-5v and a simulated 0-1v narrowband signal. EDIT: just to add, in the AEM Power desktop software the display units can be configured for lambda, AFR gasoline, AFR methanol etc etc etc, this would also need to set correctly. Quote Link to comment Share on other sites More sharing options...
bigbloodyturbo Posted May 9, 2013 Share Posted May 9, 2013 Probably not your issue but I recently had erroneous readings from my wideband which turned out to be dodgy ground offset. If it were me I'd check that the voltage your AEM says its getting from your uego matched up with the voltage (0-5v) your wideband controller is putting out. If you have a ground offset your gauge will read one thing (probably the correct reading) and your AEM will be reading something else as the AEM will be using its own ground as a reference for a signal which is actually referenced elsewhere, possibly with impedance between the two. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Thanks for the heads up. I'm pretty certain I took the power from the AEM ECU but will check. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.