New member, new to me 99 LGT...can't pass an emissions inspection....please help

I have a 99 Legacy GT 2.5 Sedan, 241k on the car, 70k on the motor. Just traded for it and had a really good feeling about it since the previous owner was a Suby technician.

 

Turns out all he had to do to pass his VA inspection was pull the bulb out of the check engine light. Now I know to test that each time I test drive a car. Didn't think to with this one though so now I'm stuck.

 

In NC we have to pass a OBD II "emissions" inspection. We don't actually have sniffers but if the car is sending out trouble codes, the car fails. I have 6 codes, two of which I think I've fixed already with plugs and wires. I'm just looking for some starting points that don't involve $600 worth of catalytic converters. Here's the codes

 

P0301 - Cylinder 1 Misfire Detected

P0302 - Cylinder 2 Misfire Detected

P0400 - Exhaust Gas Recirculation Flow

P0420 - Catalyst System Efficiency Below threshold

P0507 - Idle Control System RPM higher than expected

P1443 - P14XX Manufacturer Controlled Auxiliary Emission Controls

 

I replaced the plugs and wires and it feels like the misfires are gone. I'm not sure but after 30 it might feel like they are coming back already though. After the plugs I had the codes cleared but within 20 miles the check engine light is back on (now that I installed a check engine light).

 

How would I test the EGR valve to see if it's bad? I tested the backpressure control valve (or whatever you call it, the shop called it something different than the dealership did) and it seemed to hold a vacuum. I don't know where to go from here and I can't afford to just drop it off at the shop and tell them to fix it.

 

Thanks a million in advance and sorry if I left out critical info, I'll add it once I know what to post.

Replace all of the cars o2 sensors.

That's the 1st step? Is there any way to check them to decide if they're bad before I replace them? Working with a severely limited budget here but I do have a multimeter and I know how to use it.

 

Thanks a lot for the help whitetiger.

Check to see that the idle stop screw, or the cable for the throttle haven't been adjusted too high

Also clean out your IAC motor (be ready with a new o-ring for it just incase).

bad o2 sensors can cause all the codes you listed above.

Okeedokee, I didn't realize that I could clean the IAC. I was told by a tech friend that if I get the double misfire codes after new plugs and wires that the IAC is def the problem there.

 

I'll go get a new o ring for it tomorrow and figure out whats inside that little part.

 

Tomorrow I'm also going to clean out the C Converters. With this many miles there's no telling how old they are.

 

Any way to test the O2 sensors before replacing them? I was under the impression that EGR issues should be first on the list but I'm taking opinions from wherever I can get them at this point.

 

Thanks a lot.

bad o2 sensors can cause all the codes you listed above.

Ahhhhh, I see. Calling the parts store now. Maybe they'll have them. Is that something that's safe to get at Advance auto or should I stick with Subaru parts for those? I was told that plug wires should be Suby parts, not parts store parts.

 

Thanks again whitetiger. You da man.

 

ETA - The advance auto "OE" O2 sensors are $200 total and the subaru O2 sensors are $250. It's probably worth the extra $50? I can't either until tomorrow anyway.

Talked to the guy that I got the car from just now. He said that since I'm not getting the O2 sensor out of range code that he'd do a cat converter first. He worked on this car for a long time before he bought it and drove it for 2 years so I'm thinking what he meant was "I never replaced them so they've probably been bad for some time".

 

I'm going to order the front converter now and let the rear one ride like it is since there's no sensors back there.

 

He also said that he's seen an O2 sensor fix the problem but 9 times out of 10 it's the converter. I assume he knows what he's talking about since he's a certified technician. :crosses fingers:

 

I'm just going to tackle one code at a time. I'm still stumped about the EGR codes but I think my buddy will come over tomorrow to help with that. I can only be the EGR control valve or the little piece above that right (backpressure thingymadoodle)?

 

Unless of course whitetiger was right and it was just O2 sensors all along. I won't be surprised at all if that's the case.

Why don't you get a used set of converters off a same year 2.5L Impreza, if it doesn't bolt up (which I'd be surprised if the corresponding year didn't) then just weld the exhaust to match. You'd be surprised how low the mileage is on some of them

I just ordered a front converter from Advance. It would take forever to find a used converter from a 99 Impreza around here anyway. Then I'd still have a used converter. If the new converter doesn't stop the 420 code then I'll do a rear O2 sensor and if it's still kicking that code I'll do the front O2 I suppose.

 

That seems to be the best compromise between the different advice I've received. I'm figuring that if the O2 sensors are bad, the converter probably is too and vice versa. If the O2 sensors were cheap I'd have already replaced them but together they cost the same as the front converter...

 

Thanks guys, I really like this forum and will be sticking around for sure. It'll take me awhile before I can stop asking and start answering but that's how it goes I guess. I don't answer any questions about anything unless I'm 1000% on it. I'm teaching myself how to replace a sunroof cassette this evening (since the converter won't be in until tomorrow) so that will be one more thing I know about these neat little cars. Then I just have to figure out the total number of pieces I broke on disassembly. I'm not good with plastic.

 

Once I get it inspected all I have to do is resist the urge to mod. Must...not....mod.

I say screw it all and swap the beotch

the o2 does not have to give an out of range code. it just has to give inaccurate readings, then the car cant tune itself and you get misfire codes, fuel trim codes, and a whole sortment of other codes cause the car is just not running right. 02s are easy to replace along with the spark plugs and injectors and is a good firt attempt when trying to fix odd engine problems. if after you replace these thing and you still have problems, then you have to start digging., but 90% of the time. its the simple stuff that is the culprit.

I say screw it all and swap the beotch

 

But Kaos, this motor only has a mere 70k on it....[/whiny voice] plus, I'm unemployed so money is an issue right now. Plus, I have to sell the pickup truck ASAP and it needs some stuff before I could feel good about selling it.

 

I am following your reasoning on the O2 sensors white. I've read that many times they won't be out of range but they'll still be causing chaos. Pun tastelessly and poorly intended.

 

Thanks again you two.

 

I'll keep you updated as things progress. Or regress, whichever.

 

On another tip, changing the sunroof cassette is a real PITA but NOW I have a working sunroof! And no working pillars or headliner. Darn plastic..... need some velcro now. Hey, it's like a weight reduction job, only uglier.

I've read that many times they won't be out of range but they'll still be causing chaos.

 

Exactly. Thats when you get other codes but not o2 specific codes.

Replaced the DPFE (or back pressure transducer) today and I'm down to only code 507. Idle too high. The stupid check engine light stayed off for 50 miles today after the DPFE and a reset. I thought I was home free. They guy wasn't ready to inspect it when I got back so I went and got a burger. The light didn't come one until he pulled it into the garage! Probably could have got the sticker today if it wasn't for that yummy burger. Oh well, needed to fix the idle anyway I guess. It's a tad over 1k rpm right now.

 

I'm going to mess with the IAC once it cools off a little. I should able to get the sticker tomorrow once I reset the codes and drive it a little. I checked the throttle cables and they aren't tight when idling so I guess the IAC is the culprit. I'm going to try to just adjust it slightly and if that doesn't work, do I need a new one?

The throttle cables weren't tight so I adjusted the IAC to a nice smooth 750 rpm.

 

Maybe, just maybe, tomorrow I'll get that sticker.

Got my sticker!

 

For posterities sake, my codes were

 

P0301 - Cylinder 1 Misfire Detected - plugs and wires fixed these

P0302 - Cylinder 2 Misfire Detected - plugs and wires fixed these

P0400 - Exhaust Gas Recirculation Flow - Back pressure transducer fixed this

P0420 - Catalyst System Efficiency Below threshold - Back pressure transducer fixed this

P0507 - Idle Control System RPM higher than expected - Had to twist the Idle Air Control slightly to adjust the idle RPM

P1443 - P14XX Manufacturer Controlled Auxiliary Emission Controls - Back pressure transducer fixed this

 

Thanks a lot for all of the help.

cool, glad it worked out without too much fuss.

Yeah I figure that if I had dropped it off at the dealership and told them to "just fix it" I would have probably spent upwards of 2k. I got out with minor fuss and $130 in parts. Yay!

whats an EGR and a AIC

Iac

whats an EGR and a AIC

 

http://www.google.com/search?q=egr&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

 

Idle Air Control - on the left side of the intake IIRC.