Failed CA Smog - Royally. help?

[m3f_Mouger]

So I failed badly. Here is the basics:



Max/Measured (15)

HC 54/26

CO .50/.02

NO 430/1860 (ouch) <<< fail



Max/Measured (25)

HC 37/26

CO .47/.01

NO 717/1640 (ouch again) <<<fail



Car has 213K on it. All new MAF, o2 sensors, vacuum leaks repaired, and cats. However the cats are questionable. A friend had them done for me cheap, but they are legit carb legal. My mechanic thinks it is the cats based on the numbers. I did the 02 sensors and they are legit OEM ones. Car runs great, no bad smells, CEL codes etc. I just did the thermostat & housing and the temp gauge is dead even. Could the cats I got be total crap and need new ones? Could it be anything else based on those numbers? I need the sage advice of m3 board members. I did search and no one had NO numbers that bad. Thanks all!!!



if Cats, I am in the bay area (nor cal). Any advice on good places to help me out? Thanks!

[m3f_haus]

I'd start by checking your long and short term fuel trims, find out exactly what your coolant temp is when the engine is warm, and check to make sure your pre-cat O2 sensors are oscillating between ~0 and ~0.9. Just to get a good handle on what the motor is dealing with, because the rest of your numbers are really good. On a stock '97 with about 80K miles I've pulled 54 on the HC (very frustrating), and as low as 17 IIRC.



I'm definitely suspicious of "cheap cats a friend did". Who makes the cats? They have to be certified for the model and year; there isn't a generic carb-legal cat you can put on just any car. If I didn't know better I'd guess they put two-way cats on (hence the "cheap") but there's no way there's a carb-legal two-way cat in CA for a gasoline engine.



Are there any prior smog results on these cats or are they new for this cycle? If they were failing over a period of time the previous tests might show that.

[m3f_Mouger]

I'd start by checking your long and short term fuel trims, find out exactly what your coolant temp is when the engine is warm, and check to make sure your pre-cat O2 sensors are oscillating between ~0 and ~0.9. Just to get a good handle on what the motor is dealing with, because the rest of your numbers are really good. On a stock '97 with about 80K miles I've pulled 54 on the HC (very frustrating), and as low as 17 IIRC.



I'm definitely suspicious of "cheap cats a friend did". Who makes the cats? They have to be certified for the model and year; there isn't a generic carb-legal cat you can put on just any car. If I didn't know better I'd guess they put two-way cats on (hence the "cheap") but there's no way there's a carb-legal two-way cat in CA for a gasoline engine.



Are there any prior smog results on these cats or are they new for this cycle? If they were failing over a period of time the previous tests might show that.

Good points thanks! I replaced all the 02 sensors, and with a new maf the shop said the trim #'s looked good, but might have them re-run the tests.



I am also suspicious of "cheap" cats. They did check out as CARB legal and approved for the car, so legit. The smog place was super strict and checked the number on them. There is only a few companies that make carb legal aftermarket cats. They probably only have 200 miles or so on them. This was the first test with them since I was working out other issues to get to this point.



I will maybe have the shop run a few tests on the other stuff first before I dive in on new cats. Even Magnalfow are $500 for the pair.



Thanks!

[m3f_egebhardt]

Good points, haus.


Is that a new OEM MAF?

Aftermarket 'mod' MAF tries to tell the engine it is getting more air so it gives more fuel. I had an Ebay MAF once. It made everything worse.

An OEM MAF is ~$35 used. They work best if you want the car to work like an OEM car.


My tests with an Ebay MAF

http://www.m3forum.net/m3forum/showp...6&postcount=70

http://www.m3forum.net/m3forum/showp...9&postcount=71

[m3f_Mouger]

Good points, haus.


Is that a new OEM MAF?

Aftermarket 'mod' MAF tries to tell the engine it is getting more air so it gives more fuel. I had an Ebay MAF once. It made everything worse.

An OEM MAF is ~$35 used. They work best if you want the car to work like an OEM car.


My tests with an Ebay MAF

http://www.m3forum.net/m3forum/showp...6&postcount=70

http://www.m3forum.net/m3forum/showp...9&postcount=71

Thanks! No it is an OEM maf. I tried the $50 amazon one that was a POS. New one installed a few weeks back.


I agree, all good points. I might have the shop run my fuel trim #'s and see how that all looks. If that looks good my cats have to be the culprit. I did the O2 sensors and those were also all OEM. This has been an ongoing project just trying to get pass smog. This was a track car that was sitting when I bought it as is.

Still going to be a track car but want to be road legal so I can drive there and back. Car runs perfectly so this has been frustrating.


Thanks all.

[m3f_desertdriver]

Is your car being tested hot?

[m3f_Mouger]

Is your car being tested hot?

Yup. I drove for 20 minutes or so on the freeway in 3/4th. Came in to smog and no wait. Car was never turned off. Sat for a little while during visual but was still pretty warm. I could see being close on NO's if not super hot, but it was way, way high. I could drive around at redline but at almost 3x the max allowed I doubt it would make much of a difference.


I am 90% sure it is the cat, but will have the shop run fuel trim test to see if that is okay.


Anyone in Bay Area have any advice on good cat places if that is what I need? Or a smog place that knows what up. Hopefully one that won't fail me for a blue bimmerworld tube from maf to throttle. that guy was looking for any excuse. Because race car. Ugh!

[m3f_desertdriver]

I failed CA smog my first time due to taking it to the wrong shop. I called the PO and asked where he'd had it done and that worked.


If it's not the cats, but is instead symptomatic of a lean mixture:

1. Perhaps the new MAF could use a dousing with cleaner? Only takes a minute . . .

2. Could you still have a vacuum leak?


What would your HC / CO look like with no cat? Would you expect numbers like yours? Could you have a two-way cat system (does not reduce NOx) designed for diesel engines that somebody stuck into the housing for an M3?

[m3f_Mouger]

I failed CA smog my first time due to taking it to the wrong shop. I called the PO and asked where he'd had it done and that worked.


If it's not the cats, but is instead symptomatic of a lean mixture:

1. Perhaps the new MAF could use a dousing with cleaner? Only takes a minute . . .

2. Could you still have a vacuum leak?


What would your HC / CO look like with no cat? Would you expect numbers like yours? Could you have a two-way cat system (does not reduce NOx) designed for diesel engines that somebody stuck into the housing for an M3?

I just had a smoke test done, so vacuum leak is prob not likely. I repaired all the leaks found during the test.


Good question on what the other numbers would look like. If the cat is useless would the HC/CO numbers still be good? Anyone have smog knowledge like that?


I think the cat is not that dicey. This guy has done work for other people down in San Jose and they have passed with what he has done. These could just have been bad from the start. Cash deal so no refunds on those bad boys. I could try but not likely.


I think it could totally be running lean. Will have the shop run a fuel trim test. If those numbers look good I think the cats are my next step. Would love to do myself but behind my driveway mechanic skills/tool level. I will report back .

[m3f_LanceMach]

Anyone in Bay Area have any advice on good cat places if that is what I need? Or a smog place that knows what up. Hopefully one that won't fail me for a blue bimmerworld tube from maf to throttle. that guy was looking for any excuse. Because race car. Ugh!

Where in the Bay Area are you? I'm in the East Bay and there's a shop I really like (not that he does anything illegal, but he won't be bothered by aftermarket CARB legal parts like some shops are).

[m3f_Mouger]

Where in the Bay Area are you? I'm in the East Bay and there's a shop I really like (not that he does anything illegal, but he won't be bothered by aftermarket CARB legal parts like some shops are).

I am also in the East Bay, in the Oakland area. Everything back to stock in the motor except the tube that runs from maf to the throttle intake. Is is a blue bimmerworld replacement one vs stock black. Just seems dumb to spend money replacing it since there is no such thing as a carb legal Hose for there. If it was black he would have ignored it. If you could email me the info that would be great matt hey 2007 at gmail (no spaces). Thanks!

[m3f_LanceMach]

Coming right up!

[m3f_MMMGP]

Having those LTFTs would really help identify if there is a lean condition.


I'm thinking fuel delivery. Fuel filter, recently replaced?


Measured fuel pressure? Should be about 51psi +/- 2.9psi per Bentley manual.


What about injectors? There are a number of DIY FI kits which replace the filter and pintle caps. At 213K the injectors are probably due for servicing anyway.




Amazon.com: Little Parts BF08 - 8 Cylinder Bosch EV1 Style Fuel Injector Service Kit | Fuel Injector Cleaner Kit | Fuel Injector Repair Kit: Automotive









 








Amazon.com: Little Parts BF08 - 8 Cylinder Bosch EV1 Style Fuel Injector Service Kit | Fuel Injector Cleaner Kit | Fuel Injector Repair Kit: Automotive

[m3f_MMMGP]

Coming right up!

I used to work for a guy who had a couple of the Shelby GT500 Mustangs and a Schwarz M3 sedan with a bunch of Dinan goodies. He sure loved those GT500s!