I have a 96 c220 that won't start either...it cranks but doesn't fire. I had to have it towed to the dealership since it wouldn't start. They say that the HFM control unit is bad, but like the original poster said, that's $1500. If the OVP was bad on my car, would it cause it to not start at all? I haven't checked the part # yet but I did ask the guys at the dealership to verify it was the good part # and they had no idea what I was talking about, and said the ovp tested out okay. I thought I read elsewhere on the site that there was no way to test the OVP...is there?