Car stalling during idle

K2e2vin · 03-06-2013, 06:59 PM

Setup:
-2005 LGT with stock 32-bit ECU+modified tables
-version 9 EJ207 with EJ255 intake cams
-02-06 WRX Air Fuel/O2 sensor

This started happening randomly, though it's now more frequent, but at idle it would sometimes just turn off. Initially it would hesisitate and try to compensate(I'd say the pressure gauge losing vacuum), but still turned off. Today, it started happening while the clutch up and not necessarily at the stop light(happended again today while I was turning and also in a parking lot). Also, on a cold motor I can sometimes feel it hesitating under ~2000rpm and part throttle; so I assume it's related to something during closed loop.

I thought it may be a vacuum leak or something but I couldn't find any(I retorqued the BPV and clamps on the turbo hose to make sure).

I do have a CEL, P0131 IIRC; could that cause it? It's not the sensor itself since I replaced it and am getting the same code; I'm sure it's the ECU that can't read that range(rescaled the table to read that O2 sensor; 32bit ECU). I've ordered an OE O2 sensor but it's still in transit. Though, I've had that code for a while and it never ran this badly.

Please, any suggestions or where to look would help immensely.

Thanks!

Uncle Scotty · 03-06-2013, 07:19 PM

get the codes read...post them ALL

and replace the o2 sensor and reset the ecu and see what happens

Legatron02 · 03-06-2013, 10:45 PM

Running lean? check your inlet and post MAF boost lines

K2e2vin · 03-07-2013, 12:56 AM

Thanks!

I'll check the codes again once I get home(I'm still at work right now, left my laptop at home); but last time only P0131 showed up for both(using Learning View).

K2e2vin · 03-07-2013, 03:46 AM

Ok I got P0132 now; P0131 is still in the stored DTC area. So definitely O2 sensor? Also, I tried logging but I noticed the AFR does not change from 14.7(RomRadier Logger).

Uncle Scotty · 03-07-2013, 03:48 AM

sounds like the sensor is dead or the wiring is or both

K2e2vin · 03-07-2013, 04:50 AM

Thanks Uncle Scotty. I don't think anything is wrong with the O2 sensor(I bought it off a member that said it has about 100mi or less on there); my "old" O2 sensor that came with the swap did something similar, just not as bad; though these are I guess you can say "16-bit" O2 sensors; the scale for them are over a wider range than the newer sensors. I tried using these since the newer ones have a large flange/washer that wouldn't work with the twin-scroll downpipe. I'm assuming the ECU can't physically read how low or high that sensor is outputting. If you say it's the sensor then I'll definitely swap it out ASAP; but I'm assuming I have nothing else to worry about?

Main reason I started this thread was I don't know how much the O2 sensor(s) affect the engine. My background is in Honda so I'm still learning(with the Hondas a bad or missing O2 only affected CL/while driving; so idle, etc. isn't really affected much).

03-06-2013, 06:59 PM	#1
K2e2vin Scooby Newbie Member#: 308481 Join Date: Jan 2012 Chapter/Region: South East Location: Raleigh, NC Vehicle: 2005 Legacy GT	Car stalling during idle Setup: -2005 LGT with stock 32-bit ECU+modified tables -version 9 EJ207 with EJ255 intake cams -02-06 WRX Air Fuel/O2 sensor This started happening randomly, though it's now more frequent, but at idle it would sometimes just turn off. Initially it would hesisitate and try to compensate(I'd say the pressure gauge losing vacuum), but still turned off. Today, it started happening while the clutch up and not necessarily at the stop light(happended again today while I was turning and also in a parking lot). Also, on a cold motor I can sometimes feel it hesitating under ~2000rpm and part throttle; so I assume it's related to something during closed loop. I thought it may be a vacuum leak or something but I couldn't find any(I retorqued the BPV and clamps on the turbo hose to make sure). I do have a CEL, P0131 IIRC; could that cause it? It's not the sensor itself since I replaced it and am getting the same code; I'm sure it's the ECU that can't read that range(rescaled the table to read that O2 sensor; 32bit ECU). I've ordered an OE O2 sensor but it's still in transit. Though, I've had that code for a while and it never ran this badly. Please, any suggestions or where to look would help immensely. Thanks!

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03-06-2013, 07:19 PM	#2
Uncle Scotty NASIOC Supporter Member#: 16200 Join Date: Mar 2002 Vehicle: OK Houston we have an Uncle	get the codes read...post them ALL and replace the o2 sensor and reset the ecu and see what happens

03-06-2013, 10:45 PM	#3
Legatron02 Scooby Newbie Member#: 295810 Join Date: Sep 2011 Chapter/Region: NESIC Location: South County RI Vehicle: 98 LGT EJ205 swap Spruce Pearl	Running lean? check your inlet and post MAF boost lines

03-07-2013, 12:56 AM	#4
K2e2vin Scooby Newbie Member#: 308481 Join Date: Jan 2012 Chapter/Region: South East Location: Raleigh, NC Vehicle: 2005 Legacy GT	Thanks! I'll check the codes again once I get home(I'm still at work right now, left my laptop at home); but last time only P0131 showed up for both(using Learning View).

03-07-2013, 03:46 AM	#5
K2e2vin Scooby Newbie Member#: 308481 Join Date: Jan 2012 Chapter/Region: South East Location: Raleigh, NC Vehicle: 2005 Legacy GT	Ok I got P0132 now; P0131 is still in the stored DTC area. So definitely O2 sensor? Also, I tried logging but I noticed the AFR does not change from 14.7(RomRadier Logger).

03-07-2013, 03:48 AM	#6
Uncle Scotty NASIOC Supporter Member#: 16200 Join Date: Mar 2002 Vehicle: OK Houston we have an Uncle	sounds like the sensor is dead or the wiring is or both

03-07-2013, 04:50 AM	#7
K2e2vin Scooby Newbie Member#: 308481 Join Date: Jan 2012 Chapter/Region: South East Location: Raleigh, NC Vehicle: 2005 Legacy GT	Thanks Uncle Scotty. I don't think anything is wrong with the O2 sensor(I bought it off a member that said it has about 100mi or less on there); my "old" O2 sensor that came with the swap did something similar, just not as bad; though these are I guess you can say "16-bit" O2 sensors; the scale for them are over a wider range than the newer sensors. I tried using these since the newer ones have a large flange/washer that wouldn't work with the twin-scroll downpipe. I'm assuming the ECU can't physically read how low or high that sensor is outputting. If you say it's the sensor then I'll definitely swap it out ASAP; but I'm assuming I have nothing else to worry about? Main reason I started this thread was I don't know how much the O2 sensor(s) affect the engine. My background is in Honda so I'm still learning(with the Hondas a bad or missing O2 only affected CL/while driving; so idle, etc. isn't really affected much).