My 1988 300E will not start unless I jump the fuel pump with a straight 12 volts the engine runs until I remove the current. It does however run for a few seconds without jumping it. Maybe it runs on the intial burst when the fuel pump engages when the switch is turned to the number two position. I know sound dangerous, but a lot of forum reading got me here. Then I tried leaving it in the start number 3 position and holding it there and it runs until I let it rest in the nuber 2 position on the switch and then the engine stalls.

Now the laundry list of trouble shooting

OVP replaced
fuel pump relay replaced
all relays and modules behind the battery replaced

Maybe I should check all the main relays in the fuse box!

Help guys


What else is left, but maybe I have a bad switch and it will not let fire remain constant to the fuel pump. Wow what a leap!

All parts replaced from a freinds running 1988 300E!


Cardude,

Its getting dark and the car is not inside, no takers yet!


Cardude

Try the blower on key position 2....
if no blower , you have a bad ignition sw...

Will try that in the Morning. Had to give up for a while time for sleep. Keep it coming everyone. I wll search the forun for switch removal just in case.



Cardude

Nope the blower is working fine! Any other suggestions?


Cardude

Then the ign sw. is not suspect... try the fuse box. Benz fuses look good , but the ends sometimes do not make a good connection .. the proper way to test them is with a test light on BOTH sides of the connection [ or give them all a twist in their socket.]