1972 280 se 4.5 w108 Fuel problem!!! - PeachParts Mercedes-Benz Forum

the_turtle21 · #1 04-20-2009, 08:24 PM

ok have a 72 280 4.5 with fuel injection. the car was running fine until i arced a positive wire by the battery. no the car turns but acts like its not getting fuel. the main brain for the fuel injection....is it fuse protected??? please help.

Tomguy · #2 04-20-2009, 09:03 PM

sounds like that was the power wire for the D-Jet system including the fuel pump. Make sure it still has power from the battery to wherever you arced on the wire. Also, there are grounds behind the battery on the chassis for that system and it could have burned out one of the wires there, so check that spot. Hopefully the D-Jet box was not fried!

the_turtle21 · #3 04-20-2009, 09:18 PM

when i hook up the small positive lead i hear a click by the computer brain. well check on the grounds next.

the_turtle21 · #4 04-20-2009, 09:28 PM

the wire i arched was one that came off of the starter. in the little block of 3 wires by the battery it was the lead next to the battery. my alagator clip taped the fender and sparked.
i have also had a ignition problem with the key. i have jiggled the key ignition a little. all of the wires are still hooked up.....but could that have a started a fuel problem? i am getting spark and the car just backfires.

the_turtle21 · #5 04-20-2009, 09:43 PM

is there a way to check if the D-Jet box was fried? and well one off of a 72 280 4.5 sel fit an 4.5 se?

Tomguy · #6 04-20-2009, 10:14 PM

Any 4.5 (280SE, 280SEL, 300SEL, 450SL) D-Jet box will work.

if you shorted one of the lines on the fender to (-) then you may have just blown a relay. I believe those may be fused but not 100% sure. You either would have burned up a wire or blown a relay or fuse, not the whole brain box. I think the one you shorted sounds like the line going to the fuel pump.