gathermewool Posted March 26, 2009 Share Posted March 26, 2009 I researched as much as I possibly could, (and still do from time to time) posted up on here and nasioc.com, and even spoke with the local service guy a few times about this issue to no avail... Sorry for the long post, guys. I know the system is working so I'm not worried about my NOX emissions. I'm worried about the emissions test I've got coming up at the end of this year. I've tried to spend as little money on this as possible. I was doing well until I let the Subie tech convince me to buy the expensive Xducer...http://forums.nasioc.com/forums/images/smilies/rolleyes.gif This may only be coincidence, but the code was in last spring, early, and then went away when it got warmer. Code came back this past fall and has been around since. Here's a brief synopsis of the situation, and what I've tried. Early 2008: P0400 code (EGR flow malfunction) pops up sporadically. CEL is clear MOST of the time. As code becomes more prevalent I start researching: Haynes RM, nasioc.com, lgt.com, etc. 1. While at NOT, the EGR control system was tested by manually increasing throttle. EGR valve opened properly. EGR control system ok? 2. EGR valve opened while at idle. Engine only slightly bogs down. Dirty EGR valve? Clogged tube? 3. EGR valve cleaned, new gasket installed. Engine now bogs down considerably when EGR valve manually opened at idle. 4. Replaced all vacuum lines as well as the MAP sensor filter (suggestion from some one on nasioc.) CEL clears on its own and stays cleared for a while. 5. Fall, 2008: code comes back and does not clear. CEL on constant to-date. 6. Replaced leaking EGR tube after HT RTV "repair" failed http://forums.nasioc.com/forums/images/smilies/lol.gif 7. Subaru service guy talked me into buying a transducer, even after I told him that the EGR valve seemed to open just fine. He stated that some times, with an old EGR Xducer, it may open TOO much. Code has not cleared in the two months since I swapped them out. EGR system seems to operate EXACTLY the same. 8. Finally had some time today to do a few more checks. a. Hooked up vacuum pump to EGR valve. Applied 10" vacuum. EGR valve opened immediately, and held vacuum constant for >30 sec. I did this 5 times for repeatability. All passed. b. Checked resistance of ALL solenoid-operated vacuum valves, including EGR solenoid. All showed resistance ~40 ohms. HRM says 10-100 ohms is good. With car off, key to ON position, all solenoid connectors showed battery voltage. c. Hooked vacuum pump up to upstream side of TB. Didn't seem to show vacuum on the gauge even after I open the throttle. Downstream side showed 0 vacuum before and >10" vacuum after operating the throttle. Not sure what this means.http://forums.nasioc.com/forums/images/smilies/confused.gif '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
Reuben Posted March 27, 2009 Share Posted March 27, 2009 This all means absolutely nothing to me. Just what the is an EGR??? I'm very curious. Either way, USDM OBD-II ftl. Link to comment Share on other sites More sharing options...
987687 Posted March 27, 2009 Share Posted March 27, 2009 Either way, USDM OBD-II ftl. +1 there are about 10,000 codes that don't actually mean anything, but mess with inspection.... And EGR is exhaust gas recirculation basically puts some exhaust back into the intake to reduce emissions... STUPID STUPID STUPID. I'm glad my car doesn't have it. (a few early OBDII subies didn't have it in the US) Have you tried replacing the EGR valve all together? It seems like you have done everything besides that... Link to comment Share on other sites More sharing options...
KnifeyMcShanker Posted March 27, 2009 Share Posted March 27, 2009 A little off-topic here, but will anything bad happen if you weld the thing shut? Like, if you're not worried at all about emissions and don't want exhaust in your intake. I've been considering doing that between inspections, I have an extra one I got off a parts motor that I could swap on for tests... Link to comment Share on other sites More sharing options...
987687 Posted March 27, 2009 Share Posted March 27, 2009 Except for upsetting the ECU... I don't see why it would hurt anything... my car doesn't even have one. Link to comment Share on other sites More sharing options...
KnifeyMcShanker Posted March 27, 2009 Share Posted March 27, 2009 Yeah, I may give it a shot. I don't much like the idea of exhaust gases in my intake.... Link to comment Share on other sites More sharing options...
gathermewool Posted March 28, 2009 Author Share Posted March 28, 2009 Haynes RM says to replace the valve only if it is not able to hold vacuum. I applied 10" of vacuum and the gauge did not move at all for 30+ seconds. I'd rather not spend any money unless I'm certain it'll fix it. I was dumb enough to let the tech talk me into buying the transducer! Don't weld the EGR valve shut. All you have to do is remove the vacuum line from the solenoid to the EGR valve. This will keep the valve shut. The only problem I see with this is that carbon will probably build up very quickly with the valve always shut and, when you go to reattach it for emissions, it'll be completely clogged. Plus, unless you cap that vacuum line you'll be sucking moist air into the solenoid and transducer, causing them to gum up. Another option would be to simply remove the connector from the solenoid. This will cause the solenoid to remain shut. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
gathermewool Posted October 3, 2009 Author Share Posted October 3, 2009 I checked everything again today just to make sure there was nothing further for me to check before I take it in for some one else to diagnose. I Hooked up my vacuum pump to the vacuum line that attaches to the EGR valve, and noticed the valve open immediately and hold when I applied vacuum. For what ever reason I decided to hook up to the upstream side of the vacuum solenoid to see if I could have the EGR valve open and hold vacuum again. Upon application of vacuum the EGR valve would open and immediately shut as vacuum bled off. Multiple pumps and multiple times the EGR valve would open slightly before shutting as vacuum bled off. 1. The vacuum was applied with the solenoid unplugged. Shouldn't the solenoid be shut when denergized? Seems as if it's mechanically stuck open. 2. It seems as though the solenoid has failed, and is allowing vacuum to bleed out some where. 3. The coil resistance is 46 ohms, which is in spec. Any thoughts before I order a new one? Also, I sprayed the bolt that attaches the solenoid to the manifold with a very little bit of penetrant, but the bolt will not loosen. I'd rather not snap the bolt head. Any ideas where I can mount this if the old solenoid won't come out? '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
gathermewool Posted October 5, 2009 Author Share Posted October 5, 2009 Update: I blipped the throttle after starting the engine cold and the EGR valve slightly opened. The same thing happened with the solenoid unplugged. It's free-flowing even when I put my finger over the vent port. Also, the bolt came loose with a little bit of persuasion, so the solenoid now resides in my shirt pocket. Based on all of this I'm 97% certain the solenoid has failed mechanically. I'm going to check out a new one at the dealer to compare. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
gathermewool Posted October 5, 2009 Author Share Posted October 5, 2009 Hopefully this will be the second to last update; the last being "NO CODES FOR XX MILES!!!" Knock on wood ::knocks on head:: It is my understanding that the solenoid pulses open with a certain pulse width to open the EGR valve a specific amount for a specific period of time, and then, as eljefino stated, will shut and bleed vacuum through the filtered vent port. The old valve bled through the vent port normally, but I wasn't sure whether the valve should be open while deenergized or shut. My hope - to finally fix this freaking problem - was for it to deenergize shut, which would prove mine had failed. The local dealership parts guy let me check the new solenoid before I bought it just to make sure. I blew on one of the ports and air vented out the vent port...uh oh. I put my finger over the vent port, said a prayer, and BAM, no flow! It seems that the old valve was stuck open. A bit of "gentle" mechanical agitation and contact cleaner didn't seem to do anything so I decided to buy a new one. I was so excited I paid $10 more than I would have online just to have it right then and there. I ran over to my car and installed it in the parking lot before I left. After a bit of driving, the CEL is clear, but the readiness status is still "not ready". I have a good feeling about this, though. I'll post one last time what happens. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
Osei Posted October 7, 2009 Share Posted October 7, 2009 wonderful news, been having this issue with my BD also. Did not do the voltage diagnostics tho. replaced all but the EGR itself, but the transducer was from a wreck . Will redo all. Thanks . O. Link to comment Share on other sites More sharing options...
gathermewool Posted October 9, 2009 Author Share Posted October 9, 2009 Just passed emissions this afternoon; good for another two years! The car drives better than ever, too. No more hesitation or bogging down from a stop. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
987687 Posted October 9, 2009 Share Posted October 9, 2009 You get 2 years per sticker? Lucky! There aren't emissions tests in Maine though. Which is awesome. Link to comment Share on other sites More sharing options...
gathermewool Posted October 9, 2009 Author Share Posted October 9, 2009 No sticker. It's my understanding that I keep the document saying I passed in my glove compartment. I'm just glad I finally figured this out so I could pass. It was due 11/11 - another month if I failed exactly on the day it was due. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
Dean Prodromos Posted October 10, 2009 Share Posted October 10, 2009 I sure am glad I read this string, because this exactly described my situation. I already replaced the EGR valve itself; so now its either the transducer or the solenoid. But I never could find a good diagram of the vacuum hoses. Does anyone have one? Specifically, which port on the solenoid connects to the EGR itself? Dean Link to comment Share on other sites More sharing options...
gathermewool Posted October 11, 2009 Author Share Posted October 11, 2009 The port closest to the driver's side is the port that connects to the EGR valve, although I'm not sure it matters - it's either open or it's shut. The Haynes manual has a decent diagram. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
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