Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Well everything seemed to be setup on the pro, however tonight the AFR gauge and laptop were reading the same (most probably user error on my behalf ). The rough idle turns out to be a broken IAT sensor which was telling the ECU the intake temperature was -31 degrees. Thanks to everyone who helped. A massive thanks to Marco79 for assisting me and a another massive thank you to Wes who was an absolute star, really appreciate it! Quote Link to comment Share on other sites More sharing options...
Marco79 Posted May 9, 2013 Share Posted May 9, 2013 Well everything seemed to be setup on the pro, however tonight the AFR gauge and laptop were reading the same (most probably user error on my behalf ). The rough idle turns out to be a broken IAT sensor which was telling the ECU the intake temperature was -31 degrees. Thanks to everyone who helped. A massive thanks to Marco79 for assisting me and a another massive thank you to Wes who was an absolute star, really appreciate it! No worries mate fingers crossed you can get one tomorrow, shame mine was a different thread like kev said big thanks to wes for being the aem hotline lol Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2013 Share Posted May 9, 2013 Welcome, hopefully all will be well once the sensor is sorted Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 9, 2013 Author Share Posted May 9, 2013 Just found a calibration table so will try the resistor idea tomorrow morning. Thanks again Wes. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 10, 2013 Author Share Posted May 10, 2013 Right, another update. I currently have a resistor telling the ECU the Air Intake Temperature is 18 degrees. This hasn't cured the lean issue. The Intake Air Control Valve (IACV) appears to be sucking in too much air (the noise it's making is far greater than it sed to be). Also my boost gauge is reading -0.4 bar as opposed to -0.6bar like it used to. I have checked for leaks but can't see anything obvious. The water temperature sensor is working. Is there anything AEM wise that might be telling the IACV to open more than it should do? I have just swapped the valve with another one (not a proven working one though). Any thoughts? Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 10, 2013 Share Posted May 10, 2013 I think david p had something like this when the aem does a calibration the on the sensors, it opens them to the limit and it destroyed his iacv , Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 10, 2013 Author Share Posted May 10, 2013 I think david p had something like this when the aem does a calibration the on the sensors, it opens them to the limit and it destroyed his iacv , Thanks for the heads up. I did try a different IACV and that acted exactly the same Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 10, 2013 Share Posted May 10, 2013 Pm davidp he might be able to shed some light Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 12, 2013 Author Share Posted May 12, 2013 I've just PM'd David, thanks for the advice. Quote Link to comment Share on other sites More sharing options...
David P Posted May 12, 2013 Share Posted May 12, 2013 Kev, I'll answer you as best I can openly in the thread, just in case I get lucky and say something that might be useful for the archives. If you're sure the two readings are now the same and the sensor/ECU ring groundings are sound. You've found a dicky AIT sensor and dicked with it, fit a working one and maybe it'll work wonders. If that doesn't do the trick we'll work through the other sensors. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 12, 2013 Author Share Posted May 12, 2013 Thanks for the input David. The gauge and ECU are definitely reading the same. I'll order a new gauge and see where I am. I'm certain the issue is the idle control valve (not saying its broken as the AEM might be getting false information and relying it to the valve, but ultimately it's open too much and a lot louder than usual). Would the boost gauge read slightly higher if the valve was open too much? Quote Link to comment Share on other sites More sharing options...
David P Posted May 12, 2013 Share Posted May 12, 2013 (edited) If the gauge and ECU are singing the same song, why spend money on another? A single bullet in the right place will get this Gremlin, hunt it down one step at a time or you won't know what's going on. It's highly unlikely that more than one sensor to has upped and coincidentally died at the same time for any other reason than the shared ring-earth circuits. You've found a fault so fix it. If that doesn't do the trick and you're sure the engine temp sensor is fine, top of my list would be the TPS, but don't even think of dicking with that until you've properly fixed the dicked AIT sensor that you've dicked with, or the job could swiftly descend into a Gremlin Fest. Edited May 12, 2013 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 12, 2013 Author Share Posted May 12, 2013 Sorry David, I meant I'll get a new sensor not gauge. I totally agree with you, sort one thing at a time. I'm currently searching for a new AEM sensor, looks like I might have to import one! Quote Link to comment Share on other sites More sharing options...
Wez Posted May 12, 2013 Share Posted May 12, 2013 Try MVP Kev Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 12, 2013 Author Share Posted May 12, 2013 Just ordered one on eBay. Should be here on Tuesday. It's amazing what you can find with the part number , Thanks gents. Will report back once it's fitted. Quote Link to comment Share on other sites More sharing options...
David P Posted May 12, 2013 Share Posted May 12, 2013 (edited) A fresh UEGO sensor is my kind of Supra TLC too, but fix the damn AIT sensor first. Is the UEGO sensor fitted on top of the exhaust where it can't fill up with condensated water? Edited May 13, 2013 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Kev.O Posted May 8, 2014 Author Share Posted May 8, 2014 Wow, can't believe its been a whole year and I've not touched the car (been busy with an extension and only finished off the garage as it's been used as a builders store). So, I've changed the AIT and the AEM software displays the same AFR reading as the gauge (18). I've looked through the sensors and the coolant is displaying the correct temperature so that sensor is ruled out. Any other suggestions? It's only on idle that this issue is present. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted June 19, 2014 Author Share Posted June 19, 2014 A fresh UEGO sensor is my kind of Supra TLC too, but fix the damn AIT sensor first. Is the UEGO sensor fitted on top of the exhaust where it can't fill up with condensated water? Sorry David, just realised that I never replied to your question. The sensor in the in the mid pipe about 10 degrees from the centre line so in theory there should be any condensates water there. Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 20, 2014 Share Posted June 20, 2014 Does this only happen when you start from cold ? or does it still do it at normal temp idle ? does it rev correctly ? i only say this as a misfire would show as lean also. maybe it could be an injector issue Quote Link to comment Share on other sites More sharing options...
Pig Posted June 20, 2014 Share Posted June 20, 2014 Are there any symptoms such as high idle? Have you tried adjusting the fuel table to see if adding more fuel at idle resolves the issue? Have you got O2 feedback turned on? If the sensor has gone faulty, perhaps this may cause an issue. Although, seeing as the sensor is now reading correctly this would be unlikely. How long have you left the car running for with this issue and does the fault remain the same? Have you now replaced the faulty coolant temp sensor? Or is it still sat at +18? Feel free to save a copy of your map and I will have a look at it and compare to mine to see if I can spot any anomalies. I would also be inclined to wonder if it could be a sticky injector, especially if the car has not moved for so long. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted June 20, 2014 Author Share Posted June 20, 2014 Does this only happen when you start from cold ? or does it still do it at normal temp idle ? does it rev correctly ? i only say this as a misfire would show as lean also. maybe it could be an injector issue Are there any symptoms such as high idle? Have you tried adjusting the fuel table to see if adding more fuel at idle resolves the issue? Have you got O2 feedback turned on? If the sensor has gone faulty, perhaps this may cause an issue. Although, seeing as the sensor is now reading correctly this would be unlikely. How long have you left the car running for with this issue and does the fault remain the same? Have you now replaced the faulty coolant temp sensor? Or is it still sat at +18? Feel free to save a copy of your map and I will have a look at it and compare to mine to see if I can spot any anomalies. I would also be inclined to wonder if it could be a sticky injector, especially if the car has not moved for so long. Thanks for the replies, I'll try and answer the questions as best I can. When I first start the car it's perfect for about 5-10seconds with 14.7 on the gauge then the gauge increases to about 17.5. This happens whether the car is hot or cold. The car revs ok and when driving the car appears to be fine (I don't drive it much so forget exactly how it should be but certainly feels fine). The car has had a good run to the MOT station and the issue remained. I've changed the faulty IAT sensor and used the AEM pro to check all the other sensors change values. Wes helped me out this time last year and I'm sure we turned the O2 feed back in and off but that made no difference. Quote Link to comment Share on other sites More sharing options...
mellonman Posted June 20, 2014 Share Posted June 20, 2014 the 14.7 first of all maybe just the sensor still warming up or just the start map , next time you start your car wait for the arm to fully warm up this will go of the scale lean 18 + funny that the o2 feed back has no affect i think the problem must lie there if its not trying for find 14.7 afr in closed loop what afr are you seeing when driving and full boost full boost should be low 11's Quote Link to comment Share on other sites More sharing options...
Kev.O Posted June 20, 2014 Author Share Posted June 20, 2014 I can't be sure regarding the O2 feed back as we tried a lot that night but I do remember nothing working. I've not tried full boost as I don't want to damage things though when I put my foot down a little, the gauge goes about 12ish then once my foot is off it runs lean. Quote Link to comment Share on other sites More sharing options...
Kev.O Posted August 16, 2014 Author Share Posted August 16, 2014 (edited) Just as an update, I've removed the injectors and had them flow tested and the running lean issue has disappeared but the car now runs rich as opposed to 14.7 when slowly cruising. When I press the throttle the AFR's go lean for a second or two before the car picks up. I'm sure it never hesitated like this before. Any ideas whey it might be running rich now (apart from when I first start up and for the first 20 seconds or so)? Edited August 17, 2014 by Kev.O (see edit history) Quote Link to comment Share on other sites More sharing options...
Kev.O Posted September 25, 2016 Author Share Posted September 25, 2016 Blimey two year later and I really haven't used the car at all apart from the the MOT station and the odd short trip. I want to sort this over the winter now that I've finished renovating the house after 4 years! I used the car today to take it out garage to wash. When I blip the throttle the AFR gauge shows lean and when I slowly increase the revs all is ok until I get to about 3,000 rpm and the engine goes lean again. I have a small video I can I whatsapp of someone wants to see it? I also took a video of the fuel pressure. Any help will be appreciated. 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.