94 540i BMW emissions test failure... know why?

Question

print out says NO level is too high: 858.6 when the limit is 731.
I also have a conforti engine mgmt chip for the engine, which creates more horsepower/higher rev limiits and removes the speed limiter.
Can this chip cause this failure?

Answer 1

Yes your chip can cause your failure. But that model also fails pretty regularly on its own.
NO is oxides of nitrogen, and it is generated in your engine when there is pressure (compression) and heat above 2500 degrees F.
When you add the chip. one of the things it does is modify your ignition timing curve and base COMPUTED timing. Both of these conditions will contribute to NOx.
In addition, if your car is running hot, or if the tech did not place a fan in front of the car on a warm day, this will elevate NOx.
Finally, BMW doesn't often use an EGR valve, a device engineered to help reduce NOx, so if all of the other concerns have been addressed, then MOST LIKELY (not guaranteed) failure is going to be the Catalytic Converter.
WARNING---> do not replace the CAT until you have the tech test it.It COULD be an expensive repair that doesn't help.

Answer 2

Yes the chip can cause it to fail. As in other answers say. That being said the solution may not be to just remove the chip. Have you taken the car to anyone else to see if the oxygen sensors are working correctly? Also are you running premium gas? If not run the tank out fill up with premium and add a fuel treatment like BG 44K. I know a couple of BMW dealers who use it to help that car pass smog.

Answer 3

yeah it can, always remove the chip before emission testing and put in the original and replace afterward. Or move your registration to a friend or relatives house outside of the emission standard area.

Answer 4

yes cause ur car is running out of the normal...take chip out if u put in urself..and take test over...did u tell them u had a power chip added to ur car