idosubaru Posted September 5, 2007 Share Posted September 5, 2007 97 Impreza 2.2 liter. I've cleaned the EGR valve, replaced the EGR with a known good used one, replaced the diaphram on top, cleaned out all the passages, blew out the rubber lines, swapped the pressure sensor on the passengers side wall. EGR code is still showing and the transmission will occassionally not down shift....this is EGR related since it's somehow strung to the pressure sensor on the passengers side fender wall. swapping that didn't fix it though. so now what? since the XT6 doesn't have one, i'm not familiar with what they are or why they're there. but i HATE it. Can I remove it and get rid of the code? How will it drive? Quote Link to comment Share on other sites More sharing options...
Chip Posted September 5, 2007 Share Posted September 5, 2007 97 Impreza 2.2 liter. I've cleaned the EGR valve, replaced the EGR with a known good used one, replaced the diaphram on top, cleaned out all the passages, blew out the rubber lines, swapped the pressure sensor on the passengers side wall. EGR code is still showing and the transmission will occassionally not down shift....this is EGR related since it's somehow strung to the pressure sensor on the passengers side fender wall. swapping that didn't fix it though. so now what? since the XT6 doesn't have one, i'm not familiar with what they are or why they're there. but i HATE it. Can I remove it and get rid of the code? How will it drive? This may be a stupid question but did you remember to disconnect the battery for a few minutes in order to reset the ECU ? Quote Link to comment Share on other sites More sharing options...
avk Posted September 5, 2007 Share Posted September 5, 2007 EGR also has an actuating solenoid, although there should be a separate code if it goes bad. Don't think removing the system will get rid of the code. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted September 5, 2007 Share Posted September 5, 2007 Not sure if this is helpful, but the basic description is below: The EGR system aims at reduction of NOx by lowering the combustion temperature through re- circulation of a part of exhaust gas into cylinders via the intake manifold. This system consists of the EGR valve, EGR solenoid valve, and BPT (Back pressure transducer): The EGR valve is operated by the vacuum via a BPT from the throttle body and controls the exhaust gas flow from the exhaust manifold to the intake manifold. The EGR solenoid valve is controlled by the ECM according to the engine driving condition and opens/closes the vacuum line from the BPT to the EGR valve diaphragm. The BPT controls vacuum in order for the amount of the EGR that corresponds to the engine load to be obtained. EGR VALVE The EGR valve is situated between the exhaust manifold and collector. After opening EGR solenoid valve, EGR valve is opened for receiving throttle port pressure on diaphragm. Then, part of the exhaust gas is recirculated into collector chamber. EGR SOLENOID VALVE The EGR solenoid valve is situated between the BPT and EGR valve. EGR solenoid valve is opened by a signal emitted from the ECM. Therefore, throttle port pressure is transmitted to diaphragm of EGR valve via a BPT. BPT The BPT is installed between the throttle body and the EGR solenoid valve. The BPT, varying the throttle port vacuum that acts on the EGR valve according to the throttle opening angle and exhaust gas pressure, controls the rate of exhaust gas flow to the EGR valve. Quote Link to comment Share on other sites More sharing options...
Commuter Posted September 5, 2007 Share Posted September 5, 2007 I went thru issues on my 97 OB like this. The diaphram was torn, but that didn't solve it. Passages were clean (or cleaned). Still not solved. Vacuum lines that go under the throttle cable (at least on my car) thru little metal tubes were changed out (the metal part), just in case there was a leak there. Still not solved. You can easily bypass these temporarily with some hose to test. Solenoid was changed. Problem finally solved. About a year later, EGR code showed up again. This time, it was the sensor on the passenger strut tower that you speak of. I was also getting some slow/delayed shifts from the transmission. Once it was replaced, both problems disappeared. Did you get a new sensor, or a used one? You can rip off the EGR... car will run the same (but emissions might be a bit higher... and I don't know about passing inspections...). You WILL get the CEL though since the sensor looks for a change in manifold vacuum when the EGR valve is triggered. If it doesn't see this, CEL comes on. Commuter Quote Link to comment Share on other sites More sharing options...
idosubaru Posted September 5, 2007 Author Share Posted September 5, 2007 thanks commuter, i read through your scenario when searching. thing that pisses me off is that the transmission doesn't shift right...car will be lugging along and won't downshift to go up hills sometimes. i also swapped the solenoid, forgot about that one, still no change. yes i cleared the code, came back. i installed an EGR off another vehicle that ran fine without any CEL. but that didn't help either. i've removed all the EGR stuff, blew the lines out, soaked them in cleaner, cleaned the valve, swapped diaphragms, swapped solenoids, swapped the pressure sensor....still no change. i think i will try another solenoid but based on all the cleaning/swapping i've done i can gaurantee it's not going to fix it. if REMOVING it gets rid of the delay in shifting, i'm all about it. i don't give a rip about the CEL so long as the car runs and drives without shifting all stupid. funny things is i have a spare 1997 impreza automatic 2.2 that doesn't have an EGR valve on it, but mine does? they were identical cars, even in color. wondering if i can remove that block off plate and somehow convert mine? Quote Link to comment Share on other sites More sharing options...
avk Posted September 5, 2007 Share Posted September 5, 2007 There are two solenoids, to be exact. The other one is the switching solenoid next to the sensor. Like the sensor itself, it may only affect the feedback portion of the system. Then there's this little filter spliced into the hose between the intake and the switching solenoid. I believe someone mentioned it a long time ago. Then there can be clogged EGR passages. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted September 5, 2007 Author Share Posted September 5, 2007 two solenoids? i've replaced the one close to the EGR valve. and if there's one close to the pressure sensor on the passengers side strut tower, i've replaced that one as well. is there one i've missed? Quote Link to comment Share on other sites More sharing options...
avk Posted September 5, 2007 Share Posted September 5, 2007 So you replaced both solenoids as well as the sensor. Logically, only two possibilities are left, a blocked path between the head and the intake, or a bad ECU. My 1995 FSM makes it sound like a shorted-out solenoid may damage the ECU. Quote Link to comment Share on other sites More sharing options...
OB99W Posted September 6, 2007 Share Posted September 6, 2007 [...]EGR code is still showing and the transmission will occassionally not down shift....this is EGR related since it's somehow strung to the pressure sensor on the passengers side fender wall. swapping that didn't fix it though.[...]Specifically which code; is it P0400, or another one? If you haven't seen this already, it may help: http://endwrench.com/images/pdfs/Emissions.pdf Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.