mikeanderso Posted February 3, 2005 Share Posted February 3, 2005 Hello Everyone, About a year ago head gaskets on my '98 2.5L DOHC OBW went out. After checking this board, and looking at my options, I decided to replace the troublesome engine with a rebuilt 2.2 from CCR rather than replace the gaskets and risk it happening again. Once I got the right engine (had a mixup with CCR, original engine had an impreza intake manifold on it), the swap went pretty easy. The engine runs great. I have one question I need some help on. The 2.2 fuel evap system is plumbed for a charcoal canister in the engine bay, while the 2.5 is not. When I put in the 2.2, I bought a new canister from subaru, fabbed a mounting bracket for it, and hooked it up to the engine (I didn't like the idea of hoses that went nowhere). I'm now getting a CEL, and my mechanic tells me it's because of the evap system. My question to the board is what are the differences between the fuel evap system for the 2.5 DOHC engine compared to the 2.2? My 2.2 is from a '95 legacy, so it has EGR heads if that helps better define what kind of engine I have now. I'm curious how the two systems work, and how to start troubleshooting. I think I recall hearing somewhere that the 2.5 DOHC engine cars have a canister by the fuel tank rather than in the compartment. If that's the case, I have two canisters. The obvious question is should I disable one of them, (one in the engine compartment is probably easiest to get to) and if so, how should I plumb the hoses to make the system happy. Thanks, Mike A. Quote Link to comment Share on other sites More sharing options...
blitz Posted February 3, 2005 Share Posted February 3, 2005 Mike, Are you saying that the vehicle's original canister was located in the rear and is still there? If so, then it is the cannister that is still recieving the evaporative emissions from the fuel tank, but has no means by which to be purged at startup. Meanwhile the new canister under the hood is being purged of nothing but air at startup. Am I correct in saying that the new underhood canister is not receiving evaporative emissions from the fuel tank, because it is not connected to the fuel tank? Quote Link to comment Share on other sites More sharing options...
mikeanderso Posted February 3, 2005 Author Share Posted February 3, 2005 Hi Blitz, Okay, looking over the tech manual, the canister for the 2.5 is located in front of the fuel tank, while the canister on the 2.2 engine is located in the engine bay. When I put in the 2.2, there were two barbed fittings on the front of the engine that I connected into the two fittings on the underhood canister, and didn't think much more about it. I did nothing to the canister under the car (didn't even know it was there...) The post from Blitz makes sense, in that the canister in back is collecting fumes but is not purged, and the canister under the hood is purged but not collecting fumes. Perhaps the best way to remedy the situation is to disconnect the underhood canister, but what do I need to connect to purge the canister in the back? I'm not familiar enough with the plumbing of the evap system on the engines to know what hose does what, and goes where. Time to learn, I guess. I'll dive into my manual tonight, anybody have any words of advice? Always more to learn... Thanks! Mike A. Quote Link to comment Share on other sites More sharing options...
blitz Posted February 3, 2005 Share Posted February 3, 2005 Jeez, I'm looking through my '02 manual that I paid WAAAY to much for and I'm not finding any useful information. The basic operation of evap systems is essentially almost identical between most cars and hasn't really changed a whole lot over the years. Here's a .pdf diagram of a Toyota evap system which looks fairly typical. http://www.autoshop101.com/forms/h62.pdf It doesn't give the model year, but I'm guessing late 80's / early 90's. The sube uses an ECU controlled purge valve (solenoid) instead of the thermo-pellet looking deal on the PDF. Also I was wrong. The purge occurs after warmup, during closed loop operation, not at startup as I suggested. Quote Link to comment Share on other sites More sharing options...
mikeanderso Posted February 4, 2005 Author Share Posted February 4, 2005 Blitz, Thanks for the reply. That toyota article was the kind of general info I was looking for, just enough to get my mind wrapped around. The factory repair manual from subaru has procedures for servicing the canister, as well as the vent control solenoid valve, and the purge control solenoid valve. I'll look those over a bit. Now to figure what hose goes where... When I hooked up the 2.2, I have a neighbor with a '95 legacy with the exact engine I was putting into my car (very fortunate coincidence), so I hooked up all the hoses to match his engine. I had a couple of "extra" components (I think the vent control solenoid is in the engine compartment of the '98, and was nowhere to be found on the '95, but I can't remember exactly..). Perhaps it's time to park the cars next to each other, and trace where the hoses go. Come to think of it, there's another guy on my street with a '99 2.5 DOHC... Maybe I'll try that this weekend. Thanks for the help! I'll post how it goes. Mike A. Quote Link to comment Share on other sites More sharing options...
blitz Posted February 4, 2005 Share Posted February 4, 2005 In a nutshell, the modern evap systems have incorporated a bit more electronics into the control mechanism(s), but the principles remain. If you keep searching the net you might luck-out and find some Subaru-specific info that's reasonably close to your model year, That'll get you 95% of the way there. Good luck. Quote Link to comment Share on other sites More sharing options...
Setright Posted February 6, 2005 Share Posted February 6, 2005 Your system as-such might be okay, it could just be the canister purge valve that's gone bad. Quote Link to comment Share on other sites More sharing options...
mikeanderso Posted February 7, 2005 Author Share Posted February 7, 2005 Your system as-such might be okay, it could just be the canister purge valve that's gone bad. Is there any way to troubleshoot the valve? The repair manual details how to replace it, but how can I determine if it's bad? Mike A. Quote Link to comment Share on other sites More sharing options...
Setright Posted February 7, 2005 Share Posted February 7, 2005 ECU should store a code if the valve has failed. Quote Link to comment Share on other sites More sharing options...
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