Author Topic: fuel pump on all the time issue  (Read 1220 times)


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  • Location: Detroit, Motor City, USA
fuel pump on all the time issue
« on: 04 May 2006, 07:10 PM »
My car is a 1977 280 SE. Right now the fuel pump runs all the time with the ignition switched on and engine not running.

I thought that in the past the pump would turn on at first and then off after a bit. Maybe when the pressure built up?

Can someone tell me the right set-up and what needs to be repaired?

Thanks in advance,

1977 280 SE
1978 San Juan 23
1979 6.9 #6846


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  • Location: Finland
Re: fuel pump on all the time issue
« Reply #1 on: 05 May 2006, 06:27 AM »
This is a safety issue, so if you have a car crash and the ignition stays on then the pump will continue pouring gas somewhere, which otherwise would stop if the engine stalls.

Probably your fuel pump relay is broken or it does not exist and has been jumped by a wire. (As is the case with my SL and it never bothers me)
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)