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Old 08-11-2015, 05:07 PM   #601
Rbrate6
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Member#: 427745
Join Date: Aug 2015
Vehicle:
2006 Subaru WRX
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im having the same problem with my 06 wrx. My friend recently put on the stage 1 power package from cobbs warehouse. just under a week the code came while driving to the gas station. my accessport says im still at 14.7 a/f. i reset the code on the accessport and then turned the car off, havent driven it yet but if it comes back what/where should i be looking primarily?
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Old 12-17-2015, 12:09 AM   #602
joek92
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Member#: 353938
Join Date: Apr 2013
Location: East TN
Vehicle:
2007 STI WRB
18x8.75 +35 225/40

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I removed all the emissions stuff from beside the alternator (also unplugged the box thing) and got a P0171. I think the reason it triggered was because instead of capping the intake manifold port I just connected it to the hardline coming from underneath the manifold. If I capped both instead of connecting them it might be ok.
Since there is no complete diagram listing all the hoses and ports and what they do I guess it's easier just to leave it all there.

Put all the emissions stuff back, reset ecu, and no code.
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Old 01-26-2016, 08:19 AM   #603
WR9-2X
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Wow, when this thread was started I didn't even have my driver's license yet.


Anyways, I keep getting that pesky PO171 pop up on my 05 Saabaru with a stock 2.0. Only mod otherwise I know of is the CAI which I've had for a long time without getting a code. Car has about 180,000 miles on it. The odd thing is, I only get it when I'm at the bottom of a very steep valley on my way to work. In that quick transition from downhill to uphill it pops up every time if I go fast enough.


I've checked all my vacuum lines, sealed any questionable seals on the CAI with a bit of RTV, I clean and replace the gasket on the IACV about once a year just for cheap peace-of-mind. Any other ideas? I'm guessing either the quick change in g-force when driving through the "dip" is either loosening up a vacuum line somewhere, or that my fuel system is having trouble pumping up through the g-force. Come to think of it my fuel filter is overdue....


Anyone else ever see anything like this? Car runs and idles beautifully for 180,000 miles other than this one issue going through the steep dip.
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Old 02-04-2016, 11:00 AM   #604
lamping.ap
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Join Date: Feb 2016
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2008 Impreza, no mods, P0171.

Found no intake or exhaust leaks, sprayed MAF with cleaner and saw no change in the readings. Using my bluetooth scanner I see, at idle and car hot (coolant temp was good):

SAE.LONGFT = 29.7%
SAE.SHORTFT = 20%
SAE.MAF = 2.1 g/s
SAE.WO2S11.O2SV = 2.0 V

Any ideas? The O2 voltage is suggesting it is running lean and those trims are super rich. Is the MAF reading normal for the car hot and idling?

Car seams to run fine, but is getting poor MPGs. I also found it odd, that when I shut the engine off, car still on, the O2 voltage stayed the same. Shouldn't it drop?

Last edited by lamping.ap; 02-04-2016 at 11:13 AM. Reason: added info
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Old 02-12-2016, 12:13 AM   #605
prohispano
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Ive got this code after Engine wash , !no powerwash!,

Sympoms:
-Cold start hesistation and bad idle (after warm up and restar engine idle fine at 700rpms)
-Acceleration sluggish, even warm, at second gear it feels 0 power, but in WOT, feels as same as when it was good, no problems at full boost (stage 3 bugeye at 14 psi vf39).
-Vacuum at cold starts go to -15 and its accelerate by its own trying to stay alive.
-If i want steady 1500rpm for example, it goes to 2k and stumbles to 1000 rpm, and then it goes all high again.

What im doing?
- I clean MAF sensor with contact cleaner (OBD2 bluethooth scanner, tell me AFR at idle are 15-14:7)
-I have clean coil packs and connectors.
-I have clean IAVC idle controller
-I check all vacum lineas and negatives
-I clean even the spark plugs, they are one week new and are BKR7 NGK
-I test all Coils and they are good.

When i buy the car, it has bad Frontal o2 sensor and well, it has p0171, i install new sensor and CELS neve come back!

Please need some help.

Today i buy injector cleaners, i really dont know what it is?

PD: I even check Compression (cold engine and didnt wot ) and i get 120psi in all cylinders.

Edit two: My car is working now better than ever, i just use some injector cleaner, drive around, and now it never fails.

Last edited by prohispano; 02-13-2016 at 12:06 AM.
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Old 03-03-2016, 03:28 PM   #606
ssjeff
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Default 2014 STI p0171

2014 STI Hatch With Cobb intake

I have been pulling a p0171 code a lot. I cleaned the MAF and it looks good. It doesn't run bad so I doubt it is that. Dealer wanted to replace the upstream o2 so I did that myself with a NGK
Fuel economy seems to have picked up a little but it is still pulling the code.

Motor was just rebuilt by dealer with new short block but pulled code before this.

I have a Cobb AP but have pulled it off and still pulled codes with stock program.

Runs fine. Has the stumble at 3000-3300 but it seems that is normal for these cars.

I have narrowed it down to pulling the code while cruising at 80 mph which is right in the stumble area. It also seems to go fault when I am cruising ~80 and just start to go up a small incline on the highway.

I have been studying the web. this thread is great. I am considering making a smoke machine to check leaks and also cleaning the PCV and cleaning it.

I am almost certain it is the stumble though. I am entertaining the idea to put the cobb e85 kit on which

Any ideas?
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Old 03-24-2016, 03:16 PM   #607
ssjeff
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Quote:
Originally Posted by ssjeff View Post
2014 STI Hatch With Cobb intake

I have been pulling a p0171 code a lot. I cleaned the MAF and it looks good. It doesn't run bad so I doubt it is that. Dealer wanted to replace the upstream o2 so I did that myself with a NGK
Fuel economy seems to have picked up a little but it is still pulling the code.

Motor was just rebuilt by dealer with new short block but pulled code before this.

I have a Cobb AP but have pulled it off and still pulled codes with stock program.

Runs fine. Has the stumble at 3000-3300 but it seems that is normal for these cars.

I have narrowed it down to pulling the code while cruising at 80 mph which is right in the stumble area. It also seems to go fault when I am cruising ~80 and just start to go up a small incline on the highway.

I have been studying the web. this thread is great. I am considering making a smoke machine to check leaks and also cleaning the PCV and cleaning it.

I am almost certain it is the stumble though. I am entertaining the idea to put the cobb e85 kit on which

Any ideas?
I think I have figured mine out and I figured I would post it to help others. I bought the car with a Cobb AP and the Cobb intake. The original owner put all the tunes on the AP. He had all the tunes in fact. I guess along the way of switching from 93 to 91 I put the tune in for the stock intake. I cleaned the PCV, new upstream O2 sensor, cleaned the MAF several times, and I cleaned the air filter but the code kept coming back. While pulling the datalogs from the AP I started looking at the tunes and figured out I was not running the "SF" tune. since putting the SF tune in I have not had any issues.
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Old 04-13-2016, 06:05 PM   #608
ajj7885
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Join Date: Apr 2016
Default Hellava time

Ah yes the elusive p0171 cel. I've been fighting this code and several mechanics regarding this issue and still haven't had it solved. I have a 2011 wrx sedan with a Cobb sf air intake w/o air box, Perrin recirculating bov, invidia high flow dp, and invidia catback exhaust with a Cobb ap v3 stage 2 tune 93 octane. I have seen 3 mechanics so far without any luck. I had the maf replaced and the front o2 sensor. So far 600$ invested trying to fix this issue. I'm wondering if my dp could cause the issue? Is it the tune? The cai? Code popped about a month after installing turbo back exhaust and Cobb stage 2 tune. The car bucks while driving at low speeds occasionally backfires and idles at either high or low rpms. I was almost positive the front o2 sensor was the cause but apparently not. The smell of exhaust fumes is very pungent although no black or blue colored smoke.

Any suggestions?
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Old 05-25-2016, 09:23 AM   #609
cmiovino
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Location: Pittsburgh, PA
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2004 WRX Premium
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I'll join in here. I must state, I don't have the P0171, however my AF learning 1A number is pegged at +15%. 1B and 1C are also relatively high at 6-10%.

2004 WRX, 124k miles, Cobb turboback, SF intake, Perrin inlet, STI uppipie.

The car has always had slightly positive LTFTs, even when I bought it with just the turboback and intake. These have increased over time, but no running issues or CELs.

I've changed out the MAF and front O2 with new Denso parts. Installed a new turbo inlet. Replaced all the vacuum lines around the turbo and others. Reenforced all other vacuum/boost lines with zip ties or clamps. Sprayed carb cleaned around looking for leaks. Replaced the uppipe (by a performance Subaru shop), with all new Grimmspeed gaskets. Replaced the fuel filter about 20k miles ago. Replaced the fuel pump with an STI unit.

... yet still massively positive fuel trims. I'm actually astonished the CEL hasn't tripped yet since AF learning 1 will go to 14.8 @ idle.

The only two things left I can see if the IACV gasket and cleaning the actual unit or the PCV. Both have never been cleaned/replaced. The PCV is a bitch to get to and the intercooler isn't fun to put back on with the plastic Y-pipe.

But yet, the car runs great, no CELs. Just another story that you will need to look and change everything to find your issue if you do have the CEL. I have a feeling the CEL is only triggered if the car is under load... IE the AF learning C range.
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