Running rich?

[immortal_suby]

I have had this problem for as long as I have owned my svx. (28k) When I open the sunroof I will have a gasoline smell coming into the car. It does not smell like unburnt fuel you smell at a gas station, more like a car that is running rich. I don't smell anything with the windows and sunroof closed. I also don't smell it much if I have the windows and sunroof open due to the increased airflow. I have put in new O2 sensors, reset the ECU a few times, the air filter is a clean K&N, all the vacuum hoses are connected and not visibly worn, the charcoal canister is connected properly (but probably the original) the intake is tightened down correctly, there are no error codes in the ECU.
It is most noticeable when I am at full throttle, if I drive like an old lady I hardly smell it at all. There is black soot in the tailpipe. When I put in new plugs about 10k ago, the old plugs looked great.

I have recorded the gas mileage for as long as I have owned the car and it ranges from a high of 26 on a long highway trip down to 18-19 that I am getting now around town on this crappy oxygenated winter gas. I normally get around 21-22 around town in the summer. I always burn 93 octane or better if I can find it.

Is my next step to replace the charcoal canister? Is this something I just have to live with? Does the svx just dump tons of fuel in to prevent detonation at wide open throttle or is my car screwed?

[Aredubjay]

I'm sorry I can't tell you what's wrong, but, If my car is any indication of "normal" I have never had that problem. Full throttle or not. I bought it with 109K and I'm knocking on the door of 150K now, so, in 40K miles, I've never experienced this. Hope you find out what it is, though. Doesn't sound pleasant.

[Phast SVX]

Well i have reason to believe that you may have a slightly faulty EGR Vavle. Stands for Engine Gas Recirculation. It re-initiates unbert exhuast fumes back into the engine to control the rate of combustions. IF the vavle solenoid is stuck open, then the engine runs RICH...horribly so. This solenoid is oonly supose to be open on eve nhighway driving were it can tame out your milage. But it should have triggered a check engine light, so it may just be slightly fualty or i could be totally wrong. The vavle is like 80 and install wasnt too bad, but my dealership ordered the wrong part THREE times before getting it right. The correct valve a ssembly for my MY92 was 14774AA271 but check wiht subaruparts.com and your local dealer before ordering...i'd hate to somewhat be wrong and not have this be your problem at all. So take it to the delaer if your taht worried about it and ask them if they can troubleshoot it....tell them you think it might be an EGR solenoid.

[Phast SVX]

but, If my car is any indication of "normal" I have never had that problem

ohh come on!!!! Didnt your SVX come with a legacy transmission in it =x.....bet it was quick ? As long as it lasted, i would think it toasted quite fast.
all in fun =x

[Aredubjay]

Yeah . . . yeah . . . but it's got a REAL SVX tranny in it now . . . so . . . so . . . so . . . na na na na boo boo!
:D

[immortal_suby]

thanks phast! (why didn't I think of that?)
I think I should be able to check the operation just by revving the engine and watching the egr valve to see if it opens as rev's increase. I know it was easy to see on my wagon and opened above around 3k rpm - but it's probably buried somewhere on the svx. I replaced the egr solenoid on my wagon - it was faulty and threw a check engine code, but if the egr valve itself is stuck open it probably wouldn't trigger a code.
Looks like I have another weekend project. Thanks again for the input.

[Phast SVX]

no problem, glad i could refresh your memory....Good luck and just a hint, the Subaru manuals (even chiltons) list it in the Emisions section. good luck..i know the labor was 2.5 hrs, so it might be a ***** to get to. Yah, your diagnosis sounds right, im sure only the vacuum solenoid would trip the light.

[immortal_suby]

Looks like the EGR valve is functioning properly. It opens and closes based on engine rev's and seems to be alright. I pushed it open by hand at idle and the engine almost stalled. Does this thing hinder performance that much? I wonder what disconnecting it altogether would do? Anyone have any other ideas?

[Aredubjay]

I believe there are two different EGR components: The EGR valve and the EGR Solonoid. Can't remember where the solonoid is.

[immortal_suby]

I know this is old but I finally found out what was causing the gas smell.
Found this weekend that the intake manifold on the drivers side had 3 of the bolts loose where the 3 intake runners bolt up by the injectors. 2 of them weren't even threaded down tight enough to touch the intake and the third was very loose. I can't believe the car was running like this since I have owned it (over 50k) and didn't run lean, blow up, have bad mileage, etc...

I can now cruise sunroof-open without becoming asphyxiated and as an added bonus the car runs smoother and is definitely peppier than before.
Time to go drag race the wife and settle an old score...

[Beav]

The engine management 'sees' the leak as open throttle and richens the mixture. If you had to go through annual emissions testing you would have more then likely failed. You probably blow the O2 sensors clean often enough ;) to keep them from sooting up and malfunctioning, they would have tripped the check engine light (called a 'MIL' these days - Malfunction Indicator Lamp.)

The EGR valve introduces inert gas into the combustion process allowing timing to be run more advanced without worry of detonation. It also helps reduce emissions as such. Normally EGR valves are only opened in third and fourth gear at cruise. Yes, opening it at idle will kill the engine, so if it were stuck open the engine would stall at idle. Ask someone with a 4.3 Blazer, it's the most common bad EGR valve, these days...

Disconnecting it would be poor form, besides, if it were that easy don't you think the factory would have left it off? "Gee, let's put this valve on here and steal 65 horsepower..."

Beav