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Old 05-22-2003, 12:06 AM
New2MBZ New2MBZ is offline
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Join Date: May 2003
Location: San Diego county
Posts: 64
380SEL won't start, fuel problem (pump good)


I have not gotten anywhere with this non-starting (83') 380SEL that I purchased last week.

When cranking for the first time in a while, I hear the engine fire a few times, attemping to start but after that it just cranks over and no other sign of life.
Before I bought the car, I jumpered the sockets for pins 7 and 8 on the fuel pump relay and the pump ran and I heard activity under the air cleaner so I thought I'd just buy a new relay, plug it in and go. ha! I'm still working on the thing.

The car had spaghetti from an old (early Clifford) alarm under the dash, and I removed that (this was a few days after not being able to get it to run, so the alarm removal is not the reason it won't run). One of the splices adding the starter cutout relay circuit was not well crimped and came off in my hand so I'm glad I found that before it stranded me someday.

I have tested for spark at both the coil wire and at a spark plug wire and all is well, but I wanted to be sure. The fuel pump relay has now been replaced with a new one, but it made no difference in how the car acts. I tested the protection relay and it is fine. I loosened the fuel line fitting going into the fuel distribution block at the top of the engine, and with the fuel pump relay bypassed, I get fuel under pressure as hoped for. I've tried starting the
car while the fuel pump relay socket connectors were jumpered but no luck there.

I've studied the car's wiring diagram and there is no one circuit that is I can see that is clearly the cause of the pump not running when installed normally. Since I don't know what devices and circuits are clearly responsible, I've poked around and tested here and there but have made no conclusions.
I see the idle speed control unit, but do not see the emission control unit. Can anyone tell me for sure where the unit is? Any info on what I am most likely to have success with, by replacing? Mercedes parts are not cheap and I'd like to make an educated guess here, rather than just guess. Any help would be appreciated!

1st time Mercedes owner, 0 time Mercedes driver.
83' 380SEL 184k

Last edited by New2MBZ; 05-22-2003 at 07:11 AM.
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