Making my car run cleaner

[randoms]

I have a 93 525i 5spd, with 198,000 miles. She runs strong, and is still comfy and quiet. The problem is that the exhaust smells pretty bad, especially when she's cold. It's not burning oil smell, it's more like incomplete/not great combustion.

I change the oil every 5-6k miles, and spark plugs usually at that time. I always use synthetic. She goes through about 1.5 extra quarts between oil changes. I recently put new coils in. I live in California, so I need to get regular smog checks. The last few I needed to rev the crap out of her for 30 mins before she would pass the test.

My guess is she needs a new cat and maybe injectors. Any other ideas?

/Randoms

[healtoeit]

My guess is she needs a new cat and maybe injectors. Any other ideas?

I 2nd that, I would see how clean your air intake is as well, If it has never been cleaned/replaced that may help.

Anther thing, When you change you oil do you check and see if their is coolant in it? That could be the weird smell. If their is this could be a more serious problem, but lets not jump to conclusions!

their is my 2 cents

[randoms]

check and see if their is coolant in it?

Thanks for the tip. The oil usually looks really good; no bubbles or milky stuff, still a little translucent, just a tad darker than when it went in.

/r

[healtoeit]

Well, this is just a wild hair!

Could it be connected with the vanos somehow?

[Dave M]

Well, this is just a wild hair!

Could it be connected with the vanos somehow?

[healtoeit]

Im not going to sleep well tonight!

[Dave M]

I have a 93 525i 5spd, with 198,000 miles. She runs strong, and is still comfy and quiet. The problem is that the exhaust smells pretty bad, especially when she's cold. It's not burning oil smell, it's more like incomplete/not great combustion.

I change the oil every 5-6k miles, and spark plugs usually at that time. I always use synthetic. She goes through about 1.5 extra quarts between oil changes. I recently put new coils in. I live in California, so I need to get regular smog checks. The last few I needed to rev the crap out of her for 30 mins before she would pass the test.

My guess is she needs a new cat and maybe injectors. Any other ideas?

/Randoms

Your oil consumption isn't out of the ordinary, and if you're not burning coolant (which would smell sweet) or running rich, then you're likely on the right track with the cat. Someone with a nose for these things might be able to tell you. Do the folks who smog your car have anything to say?

Dave

[NovceGuru]

My car also smells rather bad when it's cold, 93 525i with vanos and 215k miles. I don't want to say it smells sweet, but kinda? My coolant level stays the same all summer until the coldness comes and I turn on my heat, and my heater core drinks my coolant. I'm pretty sure my cats are on their way out because I can sometimes notice a rattle coming from them, but who needs cats!