Emissions Problem - Help Please

[NY535iManual]

I've recently acquired an 89 535 5 speed, with JC chip, K&N filter and a tri-flow (cat-back) exhaust from Bavarian autosport. When I registered the car, I took it in for the required inspection and it failed the "HC" part of the emissions test, but passed the other two ("NO" and I forget the third) by a very comfortable margin. Has anyone had a similar problem? (For what its worth, I live in New York State.)

I have not had a chance yet to do a tune up (plugs, distrib rotor, cap, timing, etc.) and I hope that fresh plugs and marginally hotter spark will clear up the problem. In other Bimmers I've had an oxygen sensor go bad, but this resulted in the car failing all parts of the emission test, not just the HC, which I understand to represent unburned fuel. Could it be that the JC chip richens the mixture, and slightly fouled or worn plugs can't properly ignite the charge? Or could it be that the oxygen sensor is bad, and the engine management software is dumping too much fuel into the cylinder for the oxygen charge?

I guess I will try the tune up and see if this fixes things, but any input would be much appreciated.

Thanks.

[632 Regal]

do the tune up, make sure to change the oil right before the emmisions test. Also make sure the cats are real hot, these are farther back in the exhaust system than regular cars so explain this to the tech dudes and maybe they will let you go for a nice hot drive and pull right in to have it tested.

[willobmw]

Not sure how they do emmissions test in NY. In VA they use the machine with the rear tires or front tires (dependent on RWD or FWD) rolling along at 15 mph and again at 25 mph. A month ago with 25k miles on tune up parts, 10k on valve adjustment and oxygen sensor, original cat (115K), over 7k on 0W40 Mobil1 oil and a E.A.T. chip on a car basically not even warmed up, I passed HC, CO% and NOppm all with flying colors. If the cat is original (165k) or an aftermarket one, I suspect that could be the culprit. My E12 failed like that a few years ago. I definitely would replace the cheaper parts first with a fresh oil change (Mobil1 preferred) as previously suggested. It won't hurt.
Good Luck,
Willobmw
1990 535i

[Kalevera]

Probably a combination of a dirty intake from that crappy K&N and the use of the Conforti chip while running emissions tests. My EAT came out for the most recent test, and the car got 87 for a few weeks prior.

Fritz (my 535) ran 3.1 ppm HCs last year (limit 220 in naziland Ohio/county Cuyahoga) and did 2.4 last monday, likely due to my use of BG intake cleaner (in the intake-sucking canister, not that gas tank ****, during the summer) and a light tuneup consisting of plugs last February. The 19# injectors probably didn't hurt anything, either. Nitrous also went down; accordingly, carbon monoxide and dioxide went up...great, the car's burning more gas!

But, get rid of that shitty air filter.

best, whit

[willobmw]

Whit, Limits in VA were 81 and 88 HC ppm respectfully for 15 and 25 mph. Now I know why I see so many Bimmers in Ohio. Maybe next time I'm home to visit (Akron), I will make a trip to Cleveland.
Willobmw

[mattyb]

damn we are lucky here in OZ. no tests -yet! as long as its not blowing smoke she's right mate.

[Gayle]

HC tells us how much of the available fuel was NOT burned. (High HC = sooty smoke) Low HC is good (no soot). High HC is the result of incomplete burning of the fuel mixture. High HC can result from anything causing incomplete combustion.

Catalytic converters need heat (about 550 degrees F) and oxygen to work properly. At idle, a properly tuned engine will produce little oxygen, and exhaust termperatures may drop to well below 550 degrees F. If you take the catalyst out of the picture by allowing it to cool down, don't forget to relight it before final emission testing. Many cars which fail emissions tests do so because the catalyst isn't up to temperature, or doesn't have enough oxygen to do its job. When testing for catalyst efficiency, start and fully warm the engine. Then run it at 2500 RPM for two minutes.

more than you ever want to know about emissions

[NY535iManual]

Thanks everyone for your input. I will do the tune-up and hope I don't have to resort to replacing the cat or oxy. sensor.

Whit, you seem to have some pretty negative impressions of the K&N. What about it is problematic, and what do you think is an alternative? The factory box, or something else? Anybody else? (I've run the K&N setup on 6 or 7 different cars, and never had a problem, but have focused on cleaning them regularly, at minimum with each 3kmile oil change.)

Oh, and in case I end up having to revert to a stock chip for the test...Does anyone know where I can borrow one?

[632 Regal]

do a search on the K & N, they let in tons of dirt compared to the stock high flowing cold air intake system.

[willobmw]

I'm running a ITG Foam filter in the factory box. I have the factory chip if you need to borrow it. I'm in No.Virginia. If the JC (I had one and sold it) is like the E.A.T., I doubt if that is the problem.
Willobmw