Welcome to the North American Subaru Impreza Owners Club Friday March 29, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > FA Series Factory 2.0L Turbo Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 11-22-2022, 07:42 PM   #1
subarufunjusty
Scooby Newbie
 
Member#: 511751
Join Date: Feb 2020
Chapter/Region: TXIC
Location: Central TN
Vehicle:
2017 WRX
Silver, Flat gray

Default Is limp mode real?

Hey guys,

Some background: 17 wrx 6spd, 155,000 on the car. All stock with exception of axle back, lightweight flywheel and stronger clutch. 6th gear syncro checked out at around 100k, and I've been rolling with a 5 speed ever since. Had short block replaced due to a "money shift" 136k mi. at dealer.. has been relatively trouble free if you can call it that, after emptying my wallet. Got the old short block on a stand waiting for rebuild...Car is dailyed and driven HARD. The general consensus I've found is if you can deal with the terrible stock tune (which I will totally agree) stock, is the most reliable. The last few weeks have kept me stumped.

P0137 (bank 1 sensor2 low voltage) was thrown and noticed some less than ideal idling. Some stumbles, and especially so if ac was on. Code was cleared twice and neglected for longer than I would like to admit. 4-5 times span over 1 month. Symptoms were somewhat intermittent along with the code. Would come and go. About 1000miles have been put on the car since the code was first thrown.

P04db (Crank case vent disconnect) was thrown the day I picked up replacement 02 sensor after tracing harness and determining it to be intact. After throwing this second code, while first was still active car immediately lost all boost. Revs fast but boost will not climb and stays in vacuum. Figured it was a "limp mode" or similar since 2 codes were thrown at the same time.

Parked the car and awaited pcv lines from dealer. Got the car up and replaced pcv valve under tmic and small elbow hose. Replaced pcv line on front of motor along with harness

Got reassembled and cleared the codes, only to find they were both permanent. So cleared ecu with battery disconnect and did a couple drive cycles with 0 boost. It was depressing. Had Norah jones softly playing with my stethoscope to the firewall. Drove ~35 miles until all IM monitors were done running checks. Got home cycled key twice and checked for codes went out again.


Following my drive cycles the car was able to build boost, and drove great. Again I figured since the 2 codes were cleared and IM was done, the car had ended the limp mode.

Drove~ 50 miles to work this morning built great boost and power was back.
After a warm start at lunch car is back to zero boost. No CEL, and no codes. Pulled splash shield off again and inspected turbo piping, and all looked good. Did not smoke test, or pressure test as my speciality is paint and body. I don't feel comfortable relying on my janky regulator to not dump 300psi into my piping with a quick mis swipe of the hand.

Cleaned MAF with high dollar bs, just grasping at straws.

Seems to be running and idling great revs fast with no limit (that I have found~rpm 5k+), won't boost, no CEL, no noises other than the typical FA chatter.

Curious if y'all any suggestions, or have battled similar symptoms before.

Thanks in advance!
* Registered users of the site do not see these ads.
subarufunjusty is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 11-23-2022, 04:06 AM   #2
Dato Kuroyama
Scooby Newbie
 
Member#: 531761
Join Date: Oct 2022
Chapter/Region: SWIC
Location: Arizona
Vehicle:
2015 WRX
Black Silica Pearl

Default

Couple things,

As someone who used to daily these cars.

Do not daily the car you beat on. This platform is especially known for expensive issues. But that being said, I get its fun so, HAVE FUN (responsibly of course)

Second. It sounds like your O2 sensor may need replacing, test it with a DVOM, if its out of spec, clean the O2 sensors harness connectors contacts, if the issue persists, replace

As im typing this, im reading, and you did this, good job

Next, crank case code, check your PCV, it might have broken

And as im continuing reading, you did what I was about to suggest, good job you.

Next.... and.... you already did that


try cleaning the connector for the o2 sensor, sometimes oil gets in there.
If you live in AZ ill let you use my Vacuum tester for cheap.
Check your charge pipe, it likes to come off

If you have a datalogger, datalog could answer your question.

Good luck mate
Dato Kuroyama is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 02:59 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.