WRX choking and bucks like crazy

scoobnlude · 11-29-2012, 05:32 PM

I have an 02 WRX that started having a problem earlier this week. It would run fine one minute, then as I'm driving it would suddenly feel very weird and sluggish. When I go up to stoplights and push in the clutch, the idle would drop really low and almost die. One time it did choke itself out and die, and didn't start back up til about 5 cranks later.

I was throwing the code P1086 for the TGV sensor circuit low. Thinking this might be the issue, I replaced the sensor. Last night I took it for a short drive, and the idle still dropped low at stoplights. It still felt sluggish, especially when I gave it about 3/4 throttle. Then it would be really jumpy/bucky.

If the TGV motor would be sticking closed, it would be throwing a different code, right? Any other ideas what could be causing this loss in power and hesitation?

* Registered users of the site do not see these ads.

scoobnlude · 11-29-2012, 05:34 PM

Also thought I'd add that when this problem first developed, I could tell it was idling weird right after I started it up. If I would turn the car off, then start it back up a few seconds later it would be fine, until a few miles down the road it would start bogging again.

tommyson01 · 11-29-2012, 05:36 PM

Check the easy/inexpensive stuff first. I'd start with the air filter. Are you throwing any other codes?

scoobnlude · 11-29-2012, 05:42 PM

Only other code I'm throwing is P0037 for the rear o2 sensor, which is because of my turboback exhaust.

scoobnlude · 11-29-2012, 08:43 PM

Just took it to Autozone to get codes pulled. Ran perfect the way there. I got codes P0037 (rear o2), P1086 (TGV sensor), and now P0172 (bank 1 too rich) that I've never seen before.

I just switched the TGV sensor, is there a possibility something else is causing this code?

On the way home it started acting up again. Got very sluggish, wanting to idle at 200-300 rpms at stoplights. Eventually it stalled right before I got home, and didn't wanna start back up.

Right before it stalled, I tried revving it to prevent it from dying, but it didn't really respond to any throttle difference and kept choking. Any ideas?

Andrewxxcarlson · 11-29-2012, 09:20 PM

I hope you have a tune for that downpipe, if you do I don't think you'd be throwin that o2 code.

paulpat · 11-29-2012, 09:37 PM

A tune is not Needed for his car because it is a 02 03 wrx ONLY. But he can turn off the codes with a tactrix cable.

Like they said before. Check the easy cheap things.. clean the iacv air filter. Clean Maf. U swapped the tgv sensors or motor?

Uncle Scotty · 11-29-2012, 09:44 PM

you need a new front o2 sensor

corvallisbattery · 11-29-2012, 10:00 PM

Yep. Get a log or do a live read and observe O2 sensor voltage. Also look at short term fuel trim. That will shed more light on the O2 and be a good starting point for looking for leaks. Between your stft being + or - that will tell you a ton of info

scoobnlude · 11-30-2012, 01:28 AM

Quote:

Originally Posted by paulpat

A tune is not Needed for his car because it is a 02 03 wrx ONLY. But he can turn off the codes with a tactrix cable.

Like they said before. Check the easy cheap things.. clean the iacv air filter. Clean Maf. U swapped the tgv sensors or motor?

I do have a TurboXS UTEC for my tune, but I do not have a protune which I know would obviously be preferred. And I just swapped the sensor, because my code was for the sensor low input. If it was the motor I think there's a different code for that.

Quote:

Originally Posted by Uncle Scotty

you need a new front o2 sensor

A new front sensor? The code I'm throwing is for the rear sensor.

Quote:

Originally Posted by corvallisbattery

Yep. Get a log or do a live read and observe O2 sensor voltage. Also look at short term fuel trim. That will shed more light on the O2 and be a good starting point for looking for leaks. Between your stft being + or - that will tell you a ton of info

I tried getting some datalogs in tonight, but I messed up and the logs didn't save.

What is the O2 sensor voltage supposed to be at? My buddy that was with me said it was less than a volt, sometimes around .1 to .2.

I guess I'm not too familiar with short term fuel trim, but I know the A/F ratio was sometimes registering as "RICH" under boost, but my buddy said it also went lean (sometimes close to 20:1) for a split second when I let off of the throttle.

As for boost leaks, I don't think that is it, as I have checked around on connections and haven't noticed a drop in boost. Actually, I recently had to turn my boost down since it's gotten colder as I was getting boost spike and my boost gauge was showing a good 4 psi higher than normal.

corvallisbattery · 11-30-2012, 01:56 AM

The O2 sensor varies the supplied reference voltage based on oxygen content in the exhaust. It is capable of varying from .1 to .9 volts, .1 indicating lean exhaust and .9 indicating rich exhaust.

A condensed explanation of fuel trims: If the o2 sensor indicates that the oxygen voltage reading is .9 volts or high, the PCM interprets this as a rich condition in the exhaust and as a result decreases the amount of fuel entering the engine by shortening injector "on time". The STFT (short term fuel trims) would reflect this change. The opposite would occur when the PCM sees a lean condition. The PCM would add fuel which would be indicated by a single digit positive STFT reading. On a normal engine the front o2 sensors switch rapidly back and forth two or three times per second and the STFT would shift positive and negative single digits to add and remove fuel to compensate at a similar rate.

This little "dance" goes on to keep the air/fuel ratio at it's optimal level.

Short term fuel trims or STFT reflect immediate changes in fuel injector "on-time" while long term fuel trims or LTFT reflect changes in fuel over a longer period of time. If your STFT or LTFT readings are in the positive double digits (ten or above), this indicates the fuel system has been adding an abnormal amount of fuel than is necessary to keep the proper air/fuel ratio. It may be overcompentsating for a vacuum leak or a stuck lean o2 sensor, etc. The opposite would be true if the fuel trim readings are in the negative double digits. It would indicate that the fuel system has been taking away excessive amounts of fuel, perhaps to compensate for leaking injectors or a stuck rich o2 sensor, etc. So when experiencing o2 related issues, reading your fuel trims can indicate what the PCM has been doing over the long term and short term with regard to fuel.

Your rear O2 sensor code is for low voltage input. The internal heater element may have failed or you could have a short to ground. You can test both O2's out of the car, on a bench with a torch.

For continuously lean O2 sensor readings:

1. Check sensor output wire for possible grounding. A ground will cause a false lean signal.

2. Check the MAF sensor for proper vacuum to voltage output. A high vacuum signal will cause a lean ecu reaction. (Don't forget to check manifold vacuum first!)

3. Clogged injectors can cause a false lean condition. A cleaning may solve the problem.

4. Water contamination will cause a lean condition.

5. Low fuel pressure will cause lean conditions at any rpm or load range. Be sure to check pressure at all driving modes.

6. Exhaust leaks, especially near the sensor can pull in air and cause a false lean reading.

7. Check for proper air injection system operation. The air pump should not direct air to the exhaust ports during closed loop operation.

For continuously rich O2 sensor readings:

1. Check the fuel pressure. High readings will cause rich conditions.

2. Leaking injector(s) will cause rich exhaust.

A leak down test and/or a power balance test can usually reveal the leaker.

3. A contaminated or malfunctioning canister purge system can very easily put uncontrollable amounts of fuel into the intake manifold. Simply disconnecting the vapor hose can reveal this as your problem system.

4. Check vacuum to voltage readings at the MAF sensor. A low MAF output will cause a rich ecu reaction. (Don't forget vacuum readings again!)

5. A false tps signal can cause the system to go rich if the Ecu sees a high tps output. Check tps readings at idle and for a smooth rise to wide open throttle.

corvallisbattery · 11-30-2012, 02:02 AM

Oh and what exhaust system are you running? Anything but stock or after market with cats and your tune should have killed that rear 02 sensor code.

Alfa9er9er · 11-30-2012, 12:46 PM

Just a thought, but is it possibly transmission related? Do you have a Autotrans?

subie bro · 11-30-2012, 01:12 PM

Clean and check injectors leaks

scoobnlude · 11-30-2012, 01:54 PM

Awesome thanks for explaining that. I'll try doing a log tonight or tomorrow (and hope it doesn't stall on me again).

I'm not sure what exhaust I have rather than that the muffler is magnaflow, it was on the car when I bought it. All I know is it's a big rusty 3" pipe with no cats or anything, with a probably overly large downpipe (4" I think).

Also for when I do logging, can I do the logging right after the engine warms up, or do I have to log it while it's bogging/trying to stall? Because I can drive about 5 miles with it running fine, then after that the it starts having problems.

scoobnlude · 11-30-2012, 02:01 PM

Quote:

Originally Posted by Alfa9er9er

Just a thought, but is it possibly transmission related? Do you have a Autotrans?

Nope I have a 5 speed. Definitely engine related, it literally felt like it was firing on 1 cylinder before it died. I was at a stoplight trying to keep it running, and with it revved to 2k it was still on the verge of dying. Then it quit responding to throttle completely, barely running at 100rpms.

Alfa9er9er · 12-03-2012, 01:33 PM

Id take another look at that TGV motor. Its possible thats all it is. I once re installed mine incorrectly which cause the car to chock and jerk above 3k rpm. Same might be true for you but opposite. I dont know much about the ECU and Fuel System mapping so i cant help out with what the other guys are saying. Im not sure but if youve got a CEL wouldnt your car go into to limp mode and revert to a safe map that doesnt compensate for o2? Maybe someone could shine some light on that subject cuz i honestly dont know im just assuming. Good Luck!

Alfa9er9er · 12-03-2012, 01:44 PM

Now that i think about it i re installed the sensor incorrectly or was it the motor? hmmm it was the drivers side front one, near the A/C. None the less you should look into that first.

scoobnlude · 12-03-2012, 07:37 PM

I just installed the sensor, didn't think I needed the motor since it was throwing a low curcuit input code for the sensor. Also I realized I made the mistake of not resetting the ECU before I had the codes pulled after I replaced it. So maybe the TGV issue is solved but it's just saved in the ECU so its still showing the CEL.

Also I don't think it'd put me in limp mode, with my UTEC my CEL isn't even lit up, even though I do have codes. Closest to limp mode I've ever been was a few months ago, it would only rev to about 3.5l-4k rpms, like there was a rev limiter there it just wouldn't go past it. Not sure what that was all about, it fixed itself after a few days and hasn't happened since.

scoobnlude · 12-04-2012, 12:14 AM

Not sure how much this will help, but I logged a little at idle shortly after I started it on a cold start. I know I'm running a little on the lean side at idle, but since it's a cold start that's normal right?

(The jump to 2000 rpms was a slight rev not an idle problem)
1302 -10.4 1.4 0 00 00 15.8 +10.2 3.0 ECU. +0.0 ECU. 1.4
1309 -10.4 1.4 0 00 00 15.5 +10.1 2.9 ECU. +0.0 ECU. 1.4
1303 -10.4 1.4 0 00 00 15.4 +11.1 3.2 ECU. +0.0 ECU. 1.4
1303 -10.4 1.4 0 00 00 15.5 +10.7 2.2 ECU. +0.0 ECU. 1.4
1318 -10.6 1.4 0 00 00 15.4 +10.8 3.1 ECU. +0.0 ECU. 1.3
1290 -10.6 1.3 0 00 00 15.3 +12.5 2.6 ECU. +0.0 ECU. 1.4
1268 -10.8 1.4 0 00 00 15.2 +13.9 2.2 ECU. +0.0 ECU. 1.4
1241 -10.8 1.4 0 00 00 15.5 +16.4 2.2 ECU. +0.0 ECU. 1.4
1237 -10.8 1.4 0 00 00 16.1 +15.0 3.0 ECU. +0.0 ECU. 1.4
1288 -10.6 1.4 0 00 00 16.1 +12.5 2.7 ECU. +0.0 ECU. 1.4
1299 -10.4 1.4 0 00 00 16.1 +10.0 2.6 ECU. +0.0 ECU. 1.4
1281 -10.4 1.4 0 00 00 15.7 +10.4 3.1 ECU. +0.0 ECU. 1.4
1320 -10.4 1.4 0 00 00 15.8 +10.4 2.5 ECU. +0.0 ECU. 1.4
1313 -10.4 1.4 0 00 00 15.7 +9.4 2.2 ECU. +0.0 ECU. 1.4
1304 -10.4 1.4 0 00 00 15.4 +10.3 2.2 ECU. +0.0 ECU. 1.4
1316 -10.6 1.4 0 00 00 15.1 +10.7 3.0 ECU. +0.0 ECU. 1.4
1298 -10.6 1.3 0 00 00 15.2 +11.8 2.6 ECU. +0.0 ECU. 1.4
1288 -10.8 1.4 0 00 00 15.1 +12.8 3.1 ECU. +0.0 ECU. 1.4
1296 -10.8 1.4 0 00 00 15.2 +13.9 2.9 ECU. +0.0 ECU. 1.4
1281 -10.8 1.4 0 00 00 15.3 +13.6 3.0 ECU. +0.0 ECU. 1.4
1265 -10.8 1.4 0 00 00 15.3 +13.9 3.0 ECU. +0.0 ECU. 1.3
1329 -10.6 1.7 0 00 00 15.3 +24.2 7.2 ECU. +0.0 ECU. 1.8
1641 -9.8 2.0 0 00 00 12.6 +31.4 6.9 ECU. +0.0 ECU. 2.0
1971 -8.5 2.0 0 00 00 15.4 +36.0 7.9 ECU. +0.0 ECU. 1.7
2016 -8.3 1.5 0 00 00 16.4 +11.9 4.2 ECU. +0.0 ECU. 1.5
1883 -8.5 1.5 0 00 00 14.1 +12.1 3.3 ECU. +0.0 ECU. 1.5
1702 -9.6 1.4 0 00 00 13.9 +12.3 3.3 ECU. +0.0 ECU. 1.4
1546 -10.8 1.5 0 00 00 14.5 +20.5 3.2 ECU. +0.0 ECU. 1.5
1501 -11.0 1.5 0 00 00 15.6 +20.4 3.7 ECU. +0.0 ECU. 1.5
1465 -11.0 1.5 0 00 00 15.4 +20.4 2.5 ECU. +0.0 ECU. 1.5
1415 -10.8 1.4 0 00 00 15.2 +20.5 2.3 ECU. +0.0 ECU. 1.4
1327 -10.8 1.5 0 00 00 15.3 +20.7 3.1 ECU. +0.0 ECU. 1.4
1288 -10.6 1.4 0 00 00 15.7 +20.7 3.1 ECU. +0.0 ECU. 1.4
1235 -10.6 1.4 0 00 00 15.7 +20.7 2.7 ECU. +0.0 ECU. 1.4
1216 -10.6 1.4 0 00 00 15.8 +20.6 2.6 ECU. +0.0 ECU. 1.4
1193 -10.6 1.4 0 00 00 15.7 +20.7 2.8 ECU. +0.0 ECU. 1.4
1171 -10.6 1.4 0 00 00 15.6 +20.6 2.7 ECU. +0.0 ECU. 1.4
1134 -10.6 1.4 0 00 00 15.4 +20.8 2.6 ECU. +0.0 ECU. 1.4
1121 -10.6 1.3 0 00 00 15.2 +20.9 2.5 ECU. +0.0 ECU. 1.4
1092 -10.4 1.4 0 00 00 15.2 +20.6 2.4 ECU. +0.0 ECU. 1.4
1062 -10.4 1.4 0 00 00 15.3 +20.9 1.7 ECU. +0.0 ECU. 1.4
1032 -10.2 1.4 0 00 00 15.4 +20.7 2.2 ECU. +0.0 ECU. 1.4
1065 -10.2 1.4 0 00 00 15.5 +20.7 2.4 ECU. +0.0 ECU. 1.4
1046 -10.0 1.4 0 00 00 15.6 +18.8 2.3 ECU. +0.0 ECU. 1.4
1064 -10.0 1.4 0 00 00 15.8 +18.8 2.3 ECU. +0.0 ECU. 1.4
1036 -9.8 1.4 0 00 00 16.0 +18.8 2.2 ECU. +0.0 ECU. 1.4
1057 -9.6 1.4 0 00 00 16.1 +17.1 2.2 ECU. +0.0 ECU. 1.5
1044 -9.6 1.4 0 00 00 16.1 +15.7 2.7 ECU. +0.0 ECU. 1.4
1065 -9.4 1.4 0 00 00 16.1 +14.0 2.7 ECU. +0.0 ECU. 1.4
1049 -9.4 1.4 0 00 00 16.1 +13.3 2.6 ECU. +0.0 ECU. 1.5
1053 -9.1 1.5 0 00 00 16.2 +14.7 2.8 ECU. +0.0 ECU. 1.5
1039 -9.1 1.4 0 00 00 16.4 +13.1 2.1 ECU. +0.0 ECU. 1.5
1018 -8.9 1.5 0 00 00 16.4 +16.7 2.5 ECU. +0.0 ECU. 1.5
1074 -8.7 1.5 0 00 00 16.8 +9.4 3.8 ECU. +0.0 ECU. 1.5
1090 -8.5 1.5 0 00 00 16.2 +10.7 2.7 ECU. +0.0 ECU. 1.5
1086 -8.5 1.4 0 00 00 16.2 +13.1 3.0 ECU. +0.0 ECU. 1.5
1077 -8.5 1.5 0 00 00 16.4 +13.2 2.7 ECU. +0.0 ECU. 1.4
1043 -8.3 1.5 0 00 00 16.5 +13.6 2.7 ECU. +0.0 ECU. 1.4
1063 -8.5 1.5 0 00 00 16.7 +12.8 3.0 ECU. +0.0 ECU. 1.4
1028 -8.3 1.5 0 00 00 17.0 +14.8 2.8 ECU. +0.0 ECU. 1.5
1102 -8.3 1.5 0 00 00 17.3 +13.2 2.9 ECU. +0.0 ECU. 1.5
1055 -8.3 1.5 0 00 00 17.1 +12.3 2.7 ECU. +0.0 ECU. 1.5
1068 -8.3 1.5 0 00 00 17.1 +14.3 2.6 ECU. +0.0 ECU. 1.5
1066 -8.1 1.5 0 00 00 17.5 +12.8 3.4 ECU. +0.0 ECU. 1.5
1096 -8.1 1.5 0 00 00 17.1 +11.8 3.5 ECU. +0.0 ECU. 1.5
1096 -8.1 1.4 0 00 00 16.8 +9.7 2.8 ECU. +0.0 ECU. 1.5
1064 -8.1 1.4 0 00 00 16.5 +10.6 2.7 ECU. +0.0 ECU. 1.5
1069 -8.1 1.5 0 00 00 16.8 +13.6 2.9 ECU. +0.0 ECU. 1.5
1094 -8.3 1.5 0 00 00 17.1 +12.8 2.9 ECU. +0.0 ECU. 1.4
1085 -8.3 1.5 0 00 00 16.5 +12.9 2.7 ECU. +0.0 ECU. 1.4
1050 -8.3 1.5 0 00 00 16.5 +13.9 2.9 ECU. +0.0 ECU. 1.5
1101 -8.5 1.5 0 00 00 16.7 +11.5 2.8 ECU. +0.0 ECU. 1.5
1090 -8.5 1.4 0 00 00 16.4 +11.0 3.0 ECU. +0.0 ECU. 1.5
1103 -8.5 1.5 0 00 00 16.4 +12.1 2.8 ECU. +0.0 ECU. 1.4
1112 -8.5 1.5 0 00 00 16.2 +11.8 3.0 ECU. +0.0 ECU. 1.4
1080 -8.7 1.5 0 00 00 16.1 +10.7 2.8 ECU. +0.0 ECU. 1.5
1086 -8.7 1.5 0 00 00 16.0 +12.1 3.0 ECU. +0.0 ECU. 1.5
1119 -8.9 1.4 0 00 00 16.0 +10.7 2.9 ECU. +0.0 ECU. 1.4
1097 -8.9 1.5 0 00 00 15.8 +9.3 2.4 ECU. +0.0 ECU. 1.4

At one point after I started it up (didn't get it logged) I was watching it and it started to idle horribly (not a bouncy idle, just sounded boggy and like it was hesitating. I looked at the o2 reading on the utec dashboard and it was barely registering at about .1. All the sudden it started idling normally again, and at the same time the o2 reading shot back up to over 2. Does this tell me anything?
I will try to get logs when driving it eventually, but don't really wanna drive it much if I don't have to.

Also a possible problem I found - I popped the hood and looked around a bit. I noticed the MAF sensor has 1 of the 2 screws missing... Could this be a potential problem?

Uncle Scotty · 12-04-2012, 02:59 AM

Quote:

Originally Posted by scoobnlude

.

A new front sensor? The code I'm throwing is for the rear sensor.

sometimes a front o2 can go bad and not throw a code...they can get 'weak'....and 'dim out'

this can cause all sorts of issues

change it out unless it is less than 50k miles old

use a factory sensor from one of the online dealers as these cars are real picky about their o2 sensors.....

armintheman · 01-15-2013, 12:40 AM

sorry to bring back from the dead but did you ever find out the problem?

11-29-2012, 05:32 PM	#1
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	WRX choking and bucks like crazy I have an 02 WRX that started having a problem earlier this week. It would run fine one minute, then as I'm driving it would suddenly feel very weird and sluggish. When I go up to stoplights and push in the clutch, the idle would drop really low and almost die. One time it did choke itself out and die, and didn't start back up til about 5 cranks later. I was throwing the code P1086 for the TGV sensor circuit low. Thinking this might be the issue, I replaced the sensor. Last night I took it for a short drive, and the idle still dropped low at stoplights. It still felt sluggish, especially when I gave it about 3/4 throttle. Then it would be really jumpy/bucky. If the TGV motor would be sticking closed, it would be throwing a different code, right? Any other ideas what could be causing this loss in power and hesitation? * Registered users of the site do not see these ads.

12-03-2012, 01:44 PM	#18
Alfa9er9er Scooby Newbie Member#: 261549 Join Date: Oct 2010 Chapter/Region: SCIC Location: San Diego, CA Vehicle: 2004 Wrx World Rally Pearl Blue	Now that i think about it i re installed the sensor incorrectly or was it the motor? hmmm it was the drivers side front one, near the A/C. None the less you should look into that first. Last edited by Alfa9er9er; 12-03-2012 at 01:46 PM. Reason: left out some info

12-04-2012, 12:14 AM	#20
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	Not sure how much this will help, but I logged a little at idle shortly after I started it on a cold start. I know I'm running a little on the lean side at idle, but since it's a cold start that's normal right? (The jump to 2000 rpms was a slight rev not an idle problem) 1302 -10.4 1.4 0 00 00 15.8 +10.2 3.0 ECU. +0.0 ECU. 1.4 1309 -10.4 1.4 0 00 00 15.5 +10.1 2.9 ECU. +0.0 ECU. 1.4 1303 -10.4 1.4 0 00 00 15.4 +11.1 3.2 ECU. +0.0 ECU. 1.4 1303 -10.4 1.4 0 00 00 15.5 +10.7 2.2 ECU. +0.0 ECU. 1.4 1318 -10.6 1.4 0 00 00 15.4 +10.8 3.1 ECU. +0.0 ECU. 1.3 1290 -10.6 1.3 0 00 00 15.3 +12.5 2.6 ECU. +0.0 ECU. 1.4 1268 -10.8 1.4 0 00 00 15.2 +13.9 2.2 ECU. +0.0 ECU. 1.4 1241 -10.8 1.4 0 00 00 15.5 +16.4 2.2 ECU. +0.0 ECU. 1.4 1237 -10.8 1.4 0 00 00 16.1 +15.0 3.0 ECU. +0.0 ECU. 1.4 1288 -10.6 1.4 0 00 00 16.1 +12.5 2.7 ECU. +0.0 ECU. 1.4 1299 -10.4 1.4 0 00 00 16.1 +10.0 2.6 ECU. +0.0 ECU. 1.4 1281 -10.4 1.4 0 00 00 15.7 +10.4 3.1 ECU. +0.0 ECU. 1.4 1320 -10.4 1.4 0 00 00 15.8 +10.4 2.5 ECU. +0.0 ECU. 1.4 1313 -10.4 1.4 0 00 00 15.7 +9.4 2.2 ECU. +0.0 ECU. 1.4 1304 -10.4 1.4 0 00 00 15.4 +10.3 2.2 ECU. +0.0 ECU. 1.4 1316 -10.6 1.4 0 00 00 15.1 +10.7 3.0 ECU. +0.0 ECU. 1.4 1298 -10.6 1.3 0 00 00 15.2 +11.8 2.6 ECU. +0.0 ECU. 1.4 1288 -10.8 1.4 0 00 00 15.1 +12.8 3.1 ECU. +0.0 ECU. 1.4 1296 -10.8 1.4 0 00 00 15.2 +13.9 2.9 ECU. +0.0 ECU. 1.4 1281 -10.8 1.4 0 00 00 15.3 +13.6 3.0 ECU. +0.0 ECU. 1.4 1265 -10.8 1.4 0 00 00 15.3 +13.9 3.0 ECU. +0.0 ECU. 1.3 1329 -10.6 1.7 0 00 00 15.3 +24.2 7.2 ECU. +0.0 ECU. 1.8 1641 -9.8 2.0 0 00 00 12.6 +31.4 6.9 ECU. +0.0 ECU. 2.0 1971 -8.5 2.0 0 00 00 15.4 +36.0 7.9 ECU. +0.0 ECU. 1.7 2016 -8.3 1.5 0 00 00 16.4 +11.9 4.2 ECU. +0.0 ECU. 1.5 1883 -8.5 1.5 0 00 00 14.1 +12.1 3.3 ECU. +0.0 ECU. 1.5 1702 -9.6 1.4 0 00 00 13.9 +12.3 3.3 ECU. +0.0 ECU. 1.4 1546 -10.8 1.5 0 00 00 14.5 +20.5 3.2 ECU. +0.0 ECU. 1.5 1501 -11.0 1.5 0 00 00 15.6 +20.4 3.7 ECU. +0.0 ECU. 1.5 1465 -11.0 1.5 0 00 00 15.4 +20.4 2.5 ECU. +0.0 ECU. 1.5 1415 -10.8 1.4 0 00 00 15.2 +20.5 2.3 ECU. +0.0 ECU. 1.4 1327 -10.8 1.5 0 00 00 15.3 +20.7 3.1 ECU. +0.0 ECU. 1.4 1288 -10.6 1.4 0 00 00 15.7 +20.7 3.1 ECU. +0.0 ECU. 1.4 1235 -10.6 1.4 0 00 00 15.7 +20.7 2.7 ECU. +0.0 ECU. 1.4 1216 -10.6 1.4 0 00 00 15.8 +20.6 2.6 ECU. +0.0 ECU. 1.4 1193 -10.6 1.4 0 00 00 15.7 +20.7 2.8 ECU. +0.0 ECU. 1.4 1171 -10.6 1.4 0 00 00 15.6 +20.6 2.7 ECU. +0.0 ECU. 1.4 1134 -10.6 1.4 0 00 00 15.4 +20.8 2.6 ECU. +0.0 ECU. 1.4 1121 -10.6 1.3 0 00 00 15.2 +20.9 2.5 ECU. +0.0 ECU. 1.4 1092 -10.4 1.4 0 00 00 15.2 +20.6 2.4 ECU. +0.0 ECU. 1.4 1062 -10.4 1.4 0 00 00 15.3 +20.9 1.7 ECU. +0.0 ECU. 1.4 1032 -10.2 1.4 0 00 00 15.4 +20.7 2.2 ECU. +0.0 ECU. 1.4 1065 -10.2 1.4 0 00 00 15.5 +20.7 2.4 ECU. +0.0 ECU. 1.4 1046 -10.0 1.4 0 00 00 15.6 +18.8 2.3 ECU. +0.0 ECU. 1.4 1064 -10.0 1.4 0 00 00 15.8 +18.8 2.3 ECU. +0.0 ECU. 1.4 1036 -9.8 1.4 0 00 00 16.0 +18.8 2.2 ECU. +0.0 ECU. 1.4 1057 -9.6 1.4 0 00 00 16.1 +17.1 2.2 ECU. +0.0 ECU. 1.5 1044 -9.6 1.4 0 00 00 16.1 +15.7 2.7 ECU. +0.0 ECU. 1.4 1065 -9.4 1.4 0 00 00 16.1 +14.0 2.7 ECU. +0.0 ECU. 1.4 1049 -9.4 1.4 0 00 00 16.1 +13.3 2.6 ECU. +0.0 ECU. 1.5 1053 -9.1 1.5 0 00 00 16.2 +14.7 2.8 ECU. +0.0 ECU. 1.5 1039 -9.1 1.4 0 00 00 16.4 +13.1 2.1 ECU. +0.0 ECU. 1.5 1018 -8.9 1.5 0 00 00 16.4 +16.7 2.5 ECU. +0.0 ECU. 1.5 1074 -8.7 1.5 0 00 00 16.8 +9.4 3.8 ECU. +0.0 ECU. 1.5 1090 -8.5 1.5 0 00 00 16.2 +10.7 2.7 ECU. +0.0 ECU. 1.5 1086 -8.5 1.4 0 00 00 16.2 +13.1 3.0 ECU. +0.0 ECU. 1.5 1077 -8.5 1.5 0 00 00 16.4 +13.2 2.7 ECU. +0.0 ECU. 1.4 1043 -8.3 1.5 0 00 00 16.5 +13.6 2.7 ECU. +0.0 ECU. 1.4 1063 -8.5 1.5 0 00 00 16.7 +12.8 3.0 ECU. +0.0 ECU. 1.4 1028 -8.3 1.5 0 00 00 17.0 +14.8 2.8 ECU. +0.0 ECU. 1.5 1102 -8.3 1.5 0 00 00 17.3 +13.2 2.9 ECU. +0.0 ECU. 1.5 1055 -8.3 1.5 0 00 00 17.1 +12.3 2.7 ECU. +0.0 ECU. 1.5 1068 -8.3 1.5 0 00 00 17.1 +14.3 2.6 ECU. +0.0 ECU. 1.5 1066 -8.1 1.5 0 00 00 17.5 +12.8 3.4 ECU. +0.0 ECU. 1.5 1096 -8.1 1.5 0 00 00 17.1 +11.8 3.5 ECU. +0.0 ECU. 1.5 1096 -8.1 1.4 0 00 00 16.8 +9.7 2.8 ECU. +0.0 ECU. 1.5 1064 -8.1 1.4 0 00 00 16.5 +10.6 2.7 ECU. +0.0 ECU. 1.5 1069 -8.1 1.5 0 00 00 16.8 +13.6 2.9 ECU. +0.0 ECU. 1.5 1094 -8.3 1.5 0 00 00 17.1 +12.8 2.9 ECU. +0.0 ECU. 1.4 1085 -8.3 1.5 0 00 00 16.5 +12.9 2.7 ECU. +0.0 ECU. 1.4 1050 -8.3 1.5 0 00 00 16.5 +13.9 2.9 ECU. +0.0 ECU. 1.5 1101 -8.5 1.5 0 00 00 16.7 +11.5 2.8 ECU. +0.0 ECU. 1.5 1090 -8.5 1.4 0 00 00 16.4 +11.0 3.0 ECU. +0.0 ECU. 1.5 1103 -8.5 1.5 0 00 00 16.4 +12.1 2.8 ECU. +0.0 ECU. 1.4 1112 -8.5 1.5 0 00 00 16.2 +11.8 3.0 ECU. +0.0 ECU. 1.4 1080 -8.7 1.5 0 00 00 16.1 +10.7 2.8 ECU. +0.0 ECU. 1.5 1086 -8.7 1.5 0 00 00 16.0 +12.1 3.0 ECU. +0.0 ECU. 1.5 1119 -8.9 1.4 0 00 00 16.0 +10.7 2.9 ECU. +0.0 ECU. 1.4 1097 -8.9 1.5 0 00 00 15.8 +9.3 2.4 ECU. +0.0 ECU. 1.4 At one point after I started it up (didn't get it logged) I was watching it and it started to idle horribly (not a bouncy idle, just sounded boggy and like it was hesitating. I looked at the o2 reading on the utec dashboard and it was barely registering at about .1. All the sudden it started idling normally again, and at the same time the o2 reading shot back up to over 2. Does this tell me anything? I will try to get logs when driving it eventually, but don't really wanna drive it much if I don't have to. Also a possible problem I found - I popped the hood and looked around a bit. I noticed the MAF sensor has 1 of the 2 screws missing... Could this be a potential problem? Last edited by scoobnlude; 12-04-2012 at 12:20 AM.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

11-29-2012, 05:34 PM	#2
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	Also thought I'd add that when this problem first developed, I could tell it was idling weird right after I started it up. If I would turn the car off, then start it back up a few seconds later it would be fine, until a few miles down the road it would start bogging again.

11-29-2012, 05:36 PM	#3
tommyson01 Scooby Specialist Member#: 154579 Join Date: Jul 2007 Chapter/Region: NWIC Location: Cochabamba Vehicle: 2002 WRX Wagon PSM - Sold	Check the easy/inexpensive stuff first. I'd start with the air filter. Are you throwing any other codes?

11-29-2012, 05:42 PM	#4
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	Only other code I'm throwing is P0037 for the rear o2 sensor, which is because of my turboback exhaust.

11-29-2012, 08:43 PM	#5
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	Just took it to Autozone to get codes pulled. Ran perfect the way there. I got codes P0037 (rear o2), P1086 (TGV sensor), and now P0172 (bank 1 too rich) that I've never seen before. I just switched the TGV sensor, is there a possibility something else is causing this code? On the way home it started acting up again. Got very sluggish, wanting to idle at 200-300 rpms at stoplights. Eventually it stalled right before I got home, and didn't wanna start back up. Right before it stalled, I tried revving it to prevent it from dying, but it didn't really respond to any throttle difference and kept choking. Any ideas?

11-29-2012, 09:20 PM	#6
Andrewxxcarlson Scooby Specialist Member#: 316415 Join Date: Apr 2012 Location: Elk Grove, CA Vehicle: 2006 WRX WRB	I hope you have a tune for that downpipe, if you do I don't think you'd be throwin that o2 code.

11-29-2012, 09:37 PM	#7
paulpat Scooby Specialist Member#: 237145 Join Date: Feb 2010 Chapter/Region: SCIC Location: 562 Vehicle: 02 WRX 12 FXT	A tune is not Needed for his car because it is a 02 03 wrx ONLY. But he can turn off the codes with a tactrix cable. Like they said before. Check the easy cheap things.. clean the iacv air filter. Clean Maf. U swapped the tgv sensors or motor?

11-29-2012, 09:44 PM	#8
Uncle Scotty Scooby Guru Member#: 16200 Join Date: Mar 2002 Vehicle: OK Houston we have an Uncle	you need a new front o2 sensor

11-29-2012, 10:00 PM	#9
corvallisbattery Scooby Newbie Member#: 333030 Join Date: Sep 2012 Chapter/Region: NWIC Location: Corvallis, OR Vehicle: '05 WRX PSM	Yep. Get a log or do a live read and observe O2 sensor voltage. Also look at short term fuel trim. That will shed more light on the O2 and be a good starting point for looking for leaks. Between your stft being + or - that will tell you a ton of info

11-30-2012, 01:56 AM	#11
corvallisbattery Scooby Newbie Member#: 333030 Join Date: Sep 2012 Chapter/Region: NWIC Location: Corvallis, OR Vehicle: '05 WRX PSM	The O2 sensor varies the supplied reference voltage based on oxygen content in the exhaust. It is capable of varying from .1 to .9 volts, .1 indicating lean exhaust and .9 indicating rich exhaust. A condensed explanation of fuel trims: If the o2 sensor indicates that the oxygen voltage reading is .9 volts or high, the PCM interprets this as a rich condition in the exhaust and as a result decreases the amount of fuel entering the engine by shortening injector "on time". The STFT (short term fuel trims) would reflect this change. The opposite would occur when the PCM sees a lean condition. The PCM would add fuel which would be indicated by a single digit positive STFT reading. On a normal engine the front o2 sensors switch rapidly back and forth two or three times per second and the STFT would shift positive and negative single digits to add and remove fuel to compensate at a similar rate. This little "dance" goes on to keep the air/fuel ratio at it's optimal level. Short term fuel trims or STFT reflect immediate changes in fuel injector "on-time" while long term fuel trims or LTFT reflect changes in fuel over a longer period of time. If your STFT or LTFT readings are in the positive double digits (ten or above), this indicates the fuel system has been adding an abnormal amount of fuel than is necessary to keep the proper air/fuel ratio. It may be overcompentsating for a vacuum leak or a stuck lean o2 sensor, etc. The opposite would be true if the fuel trim readings are in the negative double digits. It would indicate that the fuel system has been taking away excessive amounts of fuel, perhaps to compensate for leaking injectors or a stuck rich o2 sensor, etc. So when experiencing o2 related issues, reading your fuel trims can indicate what the PCM has been doing over the long term and short term with regard to fuel. Your rear O2 sensor code is for low voltage input. The internal heater element may have failed or you could have a short to ground. You can test both O2's out of the car, on a bench with a torch. For continuously lean O2 sensor readings: 1. Check sensor output wire for possible grounding. A ground will cause a false lean signal. 2. Check the MAF sensor for proper vacuum to voltage output. A high vacuum signal will cause a lean ecu reaction. (Don't forget to check manifold vacuum first!) 3. Clogged injectors can cause a false lean condition. A cleaning may solve the problem. 4. Water contamination will cause a lean condition. 5. Low fuel pressure will cause lean conditions at any rpm or load range. Be sure to check pressure at all driving modes. 6. Exhaust leaks, especially near the sensor can pull in air and cause a false lean reading. 7. Check for proper air injection system operation. The air pump should not direct air to the exhaust ports during closed loop operation. For continuously rich O2 sensor readings: 1. Check the fuel pressure. High readings will cause rich conditions. 2. Leaking injector(s) will cause rich exhaust. A leak down test and/or a power balance test can usually reveal the leaker. 3. A contaminated or malfunctioning canister purge system can very easily put uncontrollable amounts of fuel into the intake manifold. Simply disconnecting the vapor hose can reveal this as your problem system. 4. Check vacuum to voltage readings at the MAF sensor. A low MAF output will cause a rich ecu reaction. (Don't forget vacuum readings again!) 5. A false tps signal can cause the system to go rich if the Ecu sees a high tps output. Check tps readings at idle and for a smooth rise to wide open throttle.

11-30-2012, 02:02 AM	#12
corvallisbattery Scooby Newbie Member#: 333030 Join Date: Sep 2012 Chapter/Region: NWIC Location: Corvallis, OR Vehicle: '05 WRX PSM	Oh and what exhaust system are you running? Anything but stock or after market with cats and your tune should have killed that rear 02 sensor code.

11-30-2012, 12:46 PM	#13
Alfa9er9er Scooby Newbie Member#: 261549 Join Date: Oct 2010 Chapter/Region: SCIC Location: San Diego, CA Vehicle: 2004 Wrx World Rally Pearl Blue	Just a thought, but is it possibly transmission related? Do you have a Autotrans?

11-30-2012, 01:12 PM	#14
subie bro Scooby Newbie Member#: 327229 Join Date: Jul 2012 Chapter/Region: South East Location: Tampa Florida Vehicle: 2005 Wrx Java Black	Clean and check injectors leaks

11-30-2012, 01:54 PM	#15
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	Awesome thanks for explaining that. I'll try doing a log tonight or tomorrow (and hope it doesn't stall on me again). I'm not sure what exhaust I have rather than that the muffler is magnaflow, it was on the car when I bought it. All I know is it's a big rusty 3" pipe with no cats or anything, with a probably overly large downpipe (4" I think). Also for when I do logging, can I do the logging right after the engine warms up, or do I have to log it while it's bogging/trying to stall? Because I can drive about 5 miles with it running fine, then after that the it starts having problems.

12-03-2012, 01:33 PM	#17
Alfa9er9er Scooby Newbie Member#: 261549 Join Date: Oct 2010 Chapter/Region: SCIC Location: San Diego, CA Vehicle: 2004 Wrx World Rally Pearl Blue	Id take another look at that TGV motor. Its possible thats all it is. I once re installed mine incorrectly which cause the car to chock and jerk above 3k rpm. Same might be true for you but opposite. I dont know much about the ECU and Fuel System mapping so i cant help out with what the other guys are saying. Im not sure but if youve got a CEL wouldnt your car go into to limp mode and revert to a safe map that doesnt compensate for o2? Maybe someone could shine some light on that subject cuz i honestly dont know im just assuming. Good Luck!

12-03-2012, 07:37 PM	#19
scoobnlude Scooby Newbie Member#: 311116 Join Date: Feb 2012 Chapter/Region: MWSOC Location: Nebraska Vehicle: 02 WRX MBP	I just installed the sensor, didn't think I needed the motor since it was throwing a low curcuit input code for the sensor. Also I realized I made the mistake of not resetting the ECU before I had the codes pulled after I replaced it. So maybe the TGV issue is solved but it's just saved in the ECU so its still showing the CEL. Also I don't think it'd put me in limp mode, with my UTEC my CEL isn't even lit up, even though I do have codes. Closest to limp mode I've ever been was a few months ago, it would only rev to about 3.5l-4k rpms, like there was a rev limiter there it just wouldn't go past it. Not sure what that was all about, it fixed itself after a few days and hasn't happened since.

01-15-2013, 12:40 AM	#22
armintheman Scooby Newbie Member#: 316460 Join Date: Apr 2012 Location: Bedford Vehicle: 2008 STI Snow White	sorry to bring back from the dead but did you ever find out the problem?