Jump to content
LegacyGT.com

1994 Legacy fails emission test


Recommended Posts

1994 Subary Legacy. Non-turbo. 4dr at sedan. 240,000 or so miles (might be 280,000). Burns a bit of oil, but maybe one quart between oil changes at the most.

 

Today it failed emissions, hydrocarbon too high. It has new plugs, new air filter, new fuel filter. Plug wires look perfect, coil is clean. Runs perfectly, no misfire that I'm aware of. Check engine light does not come on. Fuel mileage is the same as always. I haven't checked compression, but it turns over evenly fwiw.

 

What else is there that can go wrong to cause this? I hate to start throwing parts at it, but I'm thinking O2 sensor next, and then what? Any kind soul here have any experience with these older cars and emissions and know the things most likely to cause this?

 

 

At this high mileage, should I be thinking of fuel injectors? Do these need replacing after a while?

Link to comment
Share on other sites

Catalytic converters have usually burned off the last of their platinum content by 200k so although it's flowing freely, it's not converting the exhaust gases like it's supposed to. Without a CEL, and given the mileage, that is what I would look at replacing first, but I'd only bother with the front one, not the secondary one since there is no reason to do the second one given the fact that there is no O2 sensor after it.
Link to comment
Share on other sites

high HC is usually due to a bad catalytic converter or a rich condition.

 

If they sniffed it, i wouldn't blame your O2 sensor yet. Like Brighton said, probably your cat at 240k miles.

Link to comment
Share on other sites

That actually makes sense. If it was pumping a bit too much fuel for some reason (unburned fuel is what causes elevated HC after all), the converter should still catch it, and if it was too much for the converter you would think not only would it get hot (can they still do that?) and mileage would go down? It purrs like a kitten, good power, good economy. Really, nothing has changed that I've noticed. Hmm...maybe I'll price a converter replacement...we really are trying to coax just another year or two out of this old car, we've had it for almost 20 years....
Link to comment
Share on other sites

Where did you find an aftermarket cat? All I've been able to find are generic cats that have to be welded in...Midas can do it for about $300, but I'd really like to find one that actually fits.

 

Summit has both generic and aftermarket direct fit offerings.

 

Jegs has both generic and aftermarket direct fit offerings

 

Napa Auto has both generic and multiple direct fit offerings.

 

Rock Auto has both generic and multiple direct fit offerings.

 

If you find a catalytic converter that you want, I'd suggest looking on Amazon or the manufacturer's website to see if it is cheaper there.

Link to comment
Share on other sites

  • 2 weeks later...

I replaced O2 sensor, detonation sensor, plugs ( plugs were clean, did not need replacing), air filter. Took car out and got it good and hot. Test. Pass. *barely*. HC at idle was 216, limit is 220. I looked up previous tests, and the HC at idle two years ago was about 20 or 30, very low. I think this cat is on it's last legs, as nothing else seems to be wrong. Plugs were clean, tailpipe is clean, idles as smooth as can be, runs great, gets great mileage.

If we can get another two years out of it, I'll replace the cat next time around, but I don't expect it to last another two years. The transmission shifts hard and it's burning about a quart of oil every 1000 miles. My wife is a lead foot stop/go driver, and the tranny clunks every time she steps on the gas or lets off. Didn't used to do this. I've felt it slip a time or two, and I'm just waiting for it to finally die.

Link to comment
Share on other sites

So at this point I'm considering overhauling the engine and replacing the tranny with a rebuilt unit. Slap on a paint job. Reupholster interior. Yeah, it's an old car, but I just need 5-10 more years or so because in 5-10 years I'm going to retire and sell most everything I own and ... well not important, but I won't have this car after that.

 

Any thoughts or suggestions on the viability of doing this versus just retiring the car and getting something newer? I was a mechanic in a previous life, NAISE certified (those that know what that means knows how long ago that was :-) ), and I've done many engines, so the work is easy. A rebuilt tranny can still be had for about $2500 or so. My only concern would be getting parts over the course of the next ten years.

 

I know, I know, it's a personal choice - is it worth the effort, etc. But I'm still interested in opinions from others.

Link to comment
Share on other sites

I did a full rebuild on mine too, partially not by choice. I refreshed the motor instead of a full rebuild since it was running fine and had 160k on it. Then about a month after the motor was done, the trans blew itself up, so I had it rebuilt and then the cat failed about 8 months later. I replaced the cat with an aftermarket one by walker and it was a little under $300. But it's gotten to the point that yes I have more then $8k in my $1500 car, but I've been dailying it 250 miles a week for the past year and it's asked nothing of me, not a single problem aside from regular maintenance. I don't plan to sell it because I basically have to keep it given my investment, but at some point it'll get retired for a newer daily.
Link to comment
Share on other sites

I hear ya on recovering your investment...I did a rebuild of the front end, everything but the rack itself. new struts, tie rods, ball joints, wheel bearings, brakes, rebuilt calipers - the whole nine yards. Parts alone was about $1000. PS pump, alternator, radiator - still waiting for the radiator fans to go, but those are metal, not plastic, and probably have a lot of life left in them. A little here, a little there, it all adds up.

 

But then, so do payments on a replacement vehicle. I can rebuild this one and paint and upholster for the same as a year or two payments on a replacement vehicle.

Link to comment
Share on other sites

Yeah it's all about your opportunity cost to replace it with something else. My reasoning to getting a new daily is gas mileage and ABS, my cars mpg is junk <19mpg and I've had more then my fair share of close calls with non ABS short stops. On top of that, IF I slide into someone when they stop short, the car will automatically be totaled and I'll get a check for <$1k, so I priced out a 2007-2010 ecobox and with a disposable car such as that, it'll pay for itself in gas and reduction in risk to totaling my investment in the subaru.

So just do the math and see if it makes sense, that's all

Link to comment
Share on other sites

I replaced O2 sensor, detonation sensor, plugs ( plugs were clean, did not need replacing), air filter. Took car out and got it good and hot. Test. Pass. *barely*. HC at idle was 216, limit is 220. I looked up previous tests, and the HC at idle two years ago was about 20 or 30, very low. I think this cat is on it's last legs, as nothing else seems to be wrong. Plugs were clean, tailpipe is clean, idles as smooth as can be, runs great, gets great mileage.

If we can get another two years out of it, I'll replace the cat next time around, but I don't expect it to last another two years. The transmission shifts hard and it's burning about a quart of oil every 1000 miles. My wife is a lead foot stop/go driver, and the tranny clunks every time she steps on the gas or lets off. Didn't used to do this. I've felt it slip a time or two, and I'm just waiting for it to finally die.

 

what month was your car made?

it maybe a official 25 year old antique very soon. (wonder if that helps at emissions testing in your state,...it does in mine,...and you can use antique plates and insurance too).

 

I think you should sell this car ASAP before you wife actually succeeds in murdering the trans.

 

replaced the trans fluid lately? (check/ change the front and rear diff lube ever?).

 

what octane gas are you running? (wonder if high octane would help).

 

what did you use for o2 sensors. I would only use Denso in a subaru.

.

others might report funny to the ECU and cause some excess gas to get used. like they may "work" but give screwy data to the ECU. the front o2 "Air Fuel" sensor controls the whole car.

 

when you plug the car into a hand held, what does it show for emissions readiness? does it show the "catalyst" as not being ready? (I would think you could have still passed if they use the magic wand sniffer on the tail pipe)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use