Grey Market Euro Car


Hi, I have a 1985 BMW M635CSi. This model was intended for the Euro market only; this car does not have a catalytic converter. To pass modern emissions, I know I need to add a cat but is there anyway to get it running super-clean for the test?

You have a car that was not designed to meet US emissions requirements.

Prepare to spend money. Lots of money.

Good luck!

Here’s the EPA link on the subject:

Are you asking if the car can be tuned to pass inspection without a cat? I really doubt it.

You are stepping into the same Grey area where your car came from. Can you BMW pass? I am a ceritifed Emissions Inspector in PA. There are a number of things you can do…Got any friends in the biz? Where are you located? If you ask people a question while telling them something is wrong you will surely get B-slapped each time they answer. What part o the country you in?

May be a few ways to get it exempted too This all depends on what state you reside in…

And BTW I LOVE THAT CAR the 635 is one of my favs

Thanks for the replies. Just to clarify: I did add a cat.
"There are a number of things you can do…Got any friends in the biz? Where are you located?"
Blackbird: I am in Colorado. Do you have a tip for me?

How did the car get in the US in the first place?

I would suggest contacting a local BMW tuner or independent shop. They may know the in’s and out’s of these operations. It has been done and hopefully you can get hooked up with right shop.

Incredible car in performance and technology even with today’s standards. Reality is it was about 30 years ahead of its own time.

Probably a military member who shipped it home from overseas. I had friends who shipped 944’s over here while stationed in Germany. They were cheap to buy over there but they ran into problems trying to get them registered here. It was a mess and some were sold for parts just to recoupe some of their money. Regulations have probably tightened up since the early 80’s but I bet a few still get through for one reason or another.

OP might be lucky - I saw something about ‘if less than 25 years old’ on some of the sites - maybe this one’s old enough to avoid some of the regs. Worth checking…

Honestly, if you can even get past the EPA import laws, and are able to get registration for it, you are about as good as you can get.

I don’t know much about your car, but I’m guessing that it’s fuel injected.

Since you are in Colorado, the laws changed recently, and now the entire state requires emissions testing, where only the major metro areas around Denver used to need testing.

Honestly, just put in new spark plugs, wires, air filter, oil filter, and set the timing to factory specs, and if the engine is in good running condition, it should pass, if its a 3 way converter that you installed.

Oh, and it can not have a CEL on, for a car that old.


What about the safety requirements? Does your Bimmer meet them? It’s not just emissions. When you try to register a car that is not on the books, the Colorado DMV is going to ask a lot of questions.

Great questions
It should be “on the books” as it was federalized in 1985. And the paperwork said it was fitted with a cat back then. The PO must have taken the emission gear off right after it cleard customs.
My question was based on the idea that with a cat back in place, what else can I do to get it running clean. I guess I’ll just do all the obvious stuff; filters, etc… Are there any additional tricks to get her through?

Register it in another county. You will spend a ton getting it right. It involves more than just cats, there will be up stream and down stream o2 sensors involved, additions to the wiring harness and also remapping the ECM or you may need to purchase an ECM for it. Way too much trouble, either that sniff around and find a station that will test another car and place the BMW vin # in. That should be aesy and run you 100 plus the test. That vehicle is not OBD2 so all they are testing is the exhaust. Good luck, I do not miss those tests…

I think you’re in a real murky area here because the car is a 1985 model. From the 1981 model year and up vehicles used O2 sensors, ECMs, etc, etc. so a cat only would not quite cut it in my opinion.

Before '81 cars had converters but no EEC controls to speak of. You better check with your state of residence first and see if there is an exemption for a car this old.

Let me correct that a bit. Some cars had EEC controls.

I’m pretty sure that not all BMW models had cats after 1975 like US cars. They were clean without them. They could burn regular leaded gas, which was still plentiful. That was one of their selling points in that era. I can’t speak for the M635CSi as I’ve never had one. It is possible that your model never had a catalytic converter even in US trim. There are lots of good Bimmer forums. You should ask this question there.

We got BMW’s with cats. in 1986 in Switzerland. The testing that is going to have to happen is not testing at a State facility but one that reports at a Federal level dealing with imports. Then there are the safety mods that need done (like beams in the doors). I wanted to import a 1986 320 (and it was only 1988) and I could tell that the US gov was making things difficult so as to discourage this activity.

The import model had the correct gear for the US market. If this is a European model, it will meet their standards, which may or may not meet ours. If it is a US model that someone took elsewhere and you brought back to the USA, then you only need to add the catalytic converter - and anything else that was removed.

Colorado law has not changed…Only parts of the Front Range are tested, as always…Since the car is over 25 years oil, it can be registered as a “Classic”…But it still needs to be tested ONE TIME…The easiest way to accomplish this would be to install a couple of cheap aftermarket converters just for the test…