Date registered: Apr 2004
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Fuel system pressure, is there a check valve???
(1978 450SLC, US version)
I am still waiting to get my new service manual (the old one is not any good) but continue to trouble shoot my car.
Today I checked my system pressure.. just to find out that I have to go to the next store and get a new fuel pressure pump (the unit on my pump are PSI not Bar :-( I misseread the scale and it goes only to 10 PSI ).. well anyhow, when I turned the fuel supply back off I could see that the system pressure was rapidly declining (from 10PSI my max reading) to 0 within about 3 seconds.
well now my understanding of the K-Jetronic is that after the fuel tank there is the fuel pump. The fuel pump outlet is supposed to have a check valve. That pump feeds into a small pressure tank (membrane spring setup) and gous through a 2 stage fuel filter.
Now, the small pressure tank is suppose to keep the fuel pressure up even after the fuel pump did shut off.. is there a problem (NOTE I do have starting problems, it needs to crank ~5 seconds before the car starts, cold or hot the same) or does the mercedes K-Jetronic not feature such a check valve?
Thanks a lot!!!!