Hey all,

I made a thread about a year ago when I bought my '88 BMW 528E about a loud sound when accelerating (turns out I needed a partial exhaust system).

Well, now I'm back. My friends who follow behind me sometimes in their car say that I emit black smoke when accelerating. Also, my gas mileage has always been about 20 mpg on the city when my OBC says it should be at about 22.5 to 23 mpg. I'm taking this as to mean that I have too much gas being used.. so is there a way to fix that? I don't want my dream car to eat up a ton of gas when it doesn't have to.. I only get 300 miles to a 15 gallon tank.

Thanks. Let me know if there is anything I can do. I've tried the fuel system cleaner stuff once before, and it didn't help from what I could tell. I also don't drive with my AC on since I know that'll eat up even more gas.

check the readings at the ecu from the coolant temperature sensor
check fuel pressure

also you might try disconnecting the o2 sensor for a bit and see what happens, it won't hurt anything short term and if this is the problem, it will help immediately, check the OBC mpg as soon as you do this, reset the mpg and see if it goes up. If you want, pm me your phone number and I'll call to answer any questions

Sadly I know very little about the inside of my car so I wouldn't know where to start with those solutions... but thanks! I'll try them once I figure out how :)