hi,

i have a '91 525im non-vanos...and i am having tons of trouble trying to pass emissions. my hydrocarbons are still just disgustingly high. so far, i have replaced my 02 sensor, fuel injectors, and changed my spark plugs.

i have a d'sylvia chip in my car as well...could that be causing improper timing? i've thrown out the possibility of a head gasket and MAF malfunction since i would assume i would feel some sort of power loss and obvious symptoms, but there are none.

i had heard that putting HEET in your car before the test could help? anyone heard of this/done it personally?

TIA