mathis15 Posted March 28, 2022 Share Posted March 28, 2022 Before I get started, worth noting that I have absolutely scoured the forums and the googs to no avail and this is my first time posting. TL;DR ECU seems to not be engaging idle after revving or clutching out of gear post-drive and stalls unless I come out of gear without touching the clutch. Full bolt-on (minus IC and turbo) + GS EBCS, IAG AOS and e-tune, no changes to tune or setup for about two years now. Symptoms: When starting, I have to disengage the clutch immediately or it won't hold idle and will die. I can save it by feathering the throttle but as soon as I touch the gas while in neutral, I can't get it to idle again. However, if I pull the trans out of gear before coming to a stop without touching the clutch, it *usually* won't stall. Sometimes will start right back up, sometimes I have to wait 10-15sec before the starter will engage. Tried running on a Cobb OTS to verify it's not the tune, same symptoms. Watching the tach, basically looks like the RPMs slowly drop to 0. I have smoke tested and cleaned the MAF, no CEL at any point. Bumped idle +300rpm with the AccessPort and that seems to help a little with the neutral+throttle issue but not much else. In-gear everything seems fine and operates normally. Planning to swap the clutch safety switch next (part on order) but not too optimistic since I don't think it would even start up if that was bad. Any insight is greatly appreciated, this has been driving me absolutely insane for over a week now. Link to comment Share on other sites More sharing options...
Pleides Posted March 29, 2022 Share Posted March 29, 2022 Does it take a long time to crank? How are the plugs? Original MAF sensor? Link to comment Share on other sites More sharing options...
mathis15 Posted March 29, 2022 Author Share Posted March 29, 2022 Does it take a long time to crank? How are the plugs? Original MAF sensor? Cranks normally, plugs are about due (~40k mi) but I don't think they're causing any issues here, original MAF and recently cleaned. Overall the damn thing runs completely normal aside from the stalling issue. When I pull it out of gear instead of clutching to stop, revs dip aggressively but the ECU still catches it and brings it to idle. Just seems like something is happening that is causing the ECU to miss engaging idle. Update to the first post, checked the clutch switch and it's fine. Link to comment Share on other sites More sharing options...
Pleides Posted March 29, 2022 Share Posted March 29, 2022 (edited) Does it run fine if you unplug the MAF sensor? Most of us have had to replace ours by now from age or mileage and just cleaning them won't solve major MAF problems. Bad O2 sensors can cause similar issues too. How many miles on your car? If you have an Accessport or a way of logging stuff, those familiar with tuning could look at logs and potentially find stuff wrong too. Edited March 29, 2022 by Pleides Link to comment Share on other sites More sharing options...
mathis15 Posted March 29, 2022 Author Share Posted March 29, 2022 I have taken a couple logs, sent them to my tuner and got the response "I don't know" lol. If anyone would be willing to look at them I'd be happy to throw them out there. Far as the MAF goes, I did try unplugging that and my upstream O2 (not simultaneously) and there was no change aside from producing limp-mode, so I think those can both be ruled out. Pretty sure my downstream O2 was deactivated(?) as part of my tune. Link to comment Share on other sites More sharing options...
Max Capacity Posted March 29, 2022 Share Posted March 29, 2022 (edited) I'll agree most likely the downstream O2 is deactivated. Did you install NGK plugs, either NGK # 2309 or 5245 ? (I use one step colder, because they cost less) You should only use NGK's I've been trying to figure out your issue...I also coast to most stop sign's, but I push in the clutch to take it out of gear. I never just pull it out of gear. Edited March 29, 2022 by Max Capacity 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Pleides Posted March 29, 2022 Share Posted March 29, 2022 Your symptoms are all very, very similar to mine when my MAF sensor was bad. This is the one I bought. No issues since. Link to comment Share on other sites More sharing options...
Marvick08GT Posted March 29, 2022 Share Posted March 29, 2022 You are on the right track, car uses the primary A/F sensor and MAF for those adjustments. You can't just unplug, need to replace the sensor(s) that are problematic. Did you post the log? Send it to marvick0718@gmail.com Have you checked for boost/vacuum leaks? Link to comment Share on other sites More sharing options...
mathis15 Posted March 29, 2022 Author Share Posted March 29, 2022 I'll agree most likely the downstream O2 is deactivated. Did you install NGK plugs, either NGK # 2309 or 5245 ? (I use one step colder, because they cost less) You should only use NGK's I've been trying to figure out your issue...I also coast to most stop sign's, but I push in the clutch to take it out of gear. I never just pull it out of gear. Yeah that’s typically how I drive as well so this is pretty annoying. NGK plugs only, yes. Link to comment Share on other sites More sharing options...
mathis15 Posted March 29, 2022 Author Share Posted March 29, 2022 You are on the right track, car uses the primary A/F sensor and MAF for those adjustments. You can't just unplug, need to replace the sensor(s) that are problematic. Did you post the log? Send it to marvick0718@gmail.com Have you checked for boost/vacuum leaks? Just on mobile right now so can’t post yet, but I did email to you. But yes, leaks have been checked. Smoke test produced a bad BPV gasket and the vac line on my wastegate was seeping, but those have been fixed. Link to comment Share on other sites More sharing options...
mathis15 Posted March 30, 2022 Author Share Posted March 30, 2022 Here's those logs if anyone else would like to take a peek. Thanks for the help everyone! datalog68.csv datalog69.csv Link to comment Share on other sites More sharing options...
mathis15 Posted March 31, 2022 Author Share Posted March 31, 2022 Your symptoms are all very, very similar to mine when my MAF sensor was bad. This is the one I bought. No issues since. Bought which one? Was there supposed to be a link there? Link to comment Share on other sites More sharing options...
Pleides Posted March 31, 2022 Share Posted March 31, 2022 Bought which one? Was there supposed to be a link there? Yep, there sure was Denso 1976040 Mass AIR Flow Sensor https://www.amazon.com/dp/B007WMG8A0/ref=cm_sw_r_apan_i_HJ1R0XHK1C3YZP94QJX6 Link to comment Share on other sites More sharing options...
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