Please excuse this transgression. My wife's 1987 325 BMW has failed the Maryland NOx emission test which uses the tread mill method.

The reading are:
HC 1.0944
CO 10.6681
NOx 3.2379 (2.8000 is passing)
CO2 360.0925

I am told by our neighborhood gas station that I should blow out the engine with some fuel injector cleaner and then take it directly to emision control for a retest.

Idle speed is set by computer but there is an adjustment screw that can affect the idle speed... it appears to regulate the air to the intake manifold. How do I make the mixture richer (less lean)? By increasing the idle speed or decreasing it?

I was told by one mechanic to lower idle speed from 900 to 700 and by another to blow out the engine with fuel injector cleaner. (Car failed a second time at 700 RPMs from 900 but NOx improved by .5)

All hoses are tight and there are no leaks. Car probably has regular gas in it.

Can anyone tell me what to do? I did not yet blow out the engine with fuel injector cleaner.

Also the car has high miles... 275,000. Would a radiator flush help?

Thanks.

__________________
Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra