93 mercedes 300te no start intermittent

[grautorepair]

I am working on a 93 300te that intermittently is hard to start. it cranks fine but is either not getting spark or fuel. it has a code 12 inthe sysytem but I lack a 93 manual to tell me what the code is.
we here a buzzing noisefrom about the air inlet and it will start, if no buzzing noise car will not start.we tap on top and it will start.
Any help would be appreciated.

[Mick J]

Code 12 should be open or short circuit lamdba sensor heater. this would not stop the car from starting.

Fuel pump relay is a likely culprit for intermittent non starting.

[Arthur Dalton]

OVP relay , [aluminum rectangular can behind the panel, rear of battery]... tap that one ... on HFM/SFI 104 cars, that causes No spark/No fuel} as it powers ECU
There has been a part change on these .. if the old was made by Siemens. Austria, change it....

[grautorepair]

I am looking for the updated part numger for the ovp relay . according to the dealer this part has not been updated and the part number given to me is 0005406745 appreciate your help

[Arthur Dalton]

Originally posted by grautorepair
I am looking for the updated part numger for the ovp relay . according to the dealer this part has not been updated and the part number given to me is 0005406745 appreciate your help

That is the new #
the original was 000 540 52 45

Pull the one in there and see if has already been changed [ most likely, as all the orig 52 45 crapped by now]

Just replaced the OVP on my 93 300CE coupe:
- original part #: 000 540 52 45
- replacement part #: 000 540 67 45

They look very similar, although the (blue 15A) fuse is oriented differently on the new part.