C230bulldawg

background: no problem with car 2007 C230 sport. wake up one morning, shift was in reverse and dome light was on. had tried to crank once before i knew it was in reverse.
Tried cranking again. will turn over but not fire up.
have towed to MB dealer.
they run diagnostic. state that fuel pump is bad. tell me it will be 1790 to replace. i read this forum and decide i will do it.
order both parts from partsgeek. install . car still wont fire up. new pump doesnt have the two lead plug it now has 4 leads going into unit into new 4 pin connector. so that male plug is not used. I reassempled old pump and sending unit and plugged the left over plug into the old top thinking maybe I needed to complete a circuit. and the old pump ran well.

so it seems to me that its not the fuel pump or sending unit. the #4 fuse is fine and i swapped out the 20A relay and its all still the same.

what could cause a bad fuel pump on diagnostic and yet not be the fuel pump? do i need to get a dead end plug for the old pump 4 pin connector thats not used now? BTW we can smell fuel when i go to crank it>

I to cant get OBD to clear or read codes. i have to actually tyake my car to the emissions center every month becuiase i cant get rid of check engine light.

i do have a thermostat stuck open and this is causing a crankshaft position sensor false reading ( learned from another forum page) but dealer says to fix that is $3600.

not sure if i have a crank sensor code or not.

so i am now 170 in the hole if you include the renatl car and no closer to understanding what is wrong.