I searched for a minute and didnt find exactly what i needed. My question is: My car cranks alot before it starts, hot or cold. Shouldn't the fuel pump run once the car is turned on? It seems as though it only pumps while im cranking and then will start after cranking for a bit. The pump will also run if i press on the sensor plate on the throttle body...Is this common? Could it be a bad relay? Everything else seems to check out what else should i check? EDIT: If it is indeed the relay, where is it located? Thanks in advance

It sounds like the relay is working fine. The pump only runs when cranking or if the air plate is moved off of the safety switch.

You probably need an some parts centered around the accumulator, check valve, pressure regulator. Sorry I can't be more specific but I'm drawing a blank right now and rather than dispense bad advice, I'll let someone else list the parts.

Michael

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Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

on yer model the pump starts only when cranking or running.
most likely you have an internal fuel pressure loss. most times
its the fuel accumulator. need to install a fuel pressure gauge
and trace the problem. kinda gets involved.
small rubber hose to the fuel accumulator needs to be pinched
off. then disconnect from the accumulator. start the car up.
if fuel comes out of the accumulator fitting for awhile then you
found yer problem. be very carefull messing around with fuel!!!!

george