Fuel pump runs and does not run...

  • Hello friends I probably have an electrical problem.

    The fuel pump runs, then the 911 starts perfectly after a short drive, the car is parked and then the fuel pump stops running.

    I left the car overnight and the next day the pump runs again, but after a short drive the same thing happens again!

    Do you have any idea where the electrical problem is?

    Pump is 1 year old.

    Is the round one on the fuse strip the fuel pump relay or is it in the back of the engine compartment?

    Many thanks in advance

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    Porsche 911 Targa Saharabeige G 2.7 November 73

    schöne Grüße

    Roman

  • Hello Roman.

    First clean the fuse contacts. And check the cables in the screw terminals.

    Greetings

    Claus

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  • Sounds like a DME relay. Simply remove, open and re-solder if necessary.

    Otherwise, invest 30 euros.

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    Wenn Du Deinen Traum-11er fährst,ist das Leben.Alles, was davor oder danach passiert,ist nur Warten

  • Hello Munga.

    Sounds like the fuel pump relay to me too.

    If it is the 2.7 from the footer, I would have a look there.

    DME relays are only available with the Motronic from 1984 onwards in the 3.2.

    Greetings Stefan

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    alte Porsches:
    911S Ex US '76 mit Umbau auf 3,2l 207PS (Motor 930/21 mit Getriebe 915/68) - Silbermetallic, Schiebedach

    911SC Targa Ex US '81 3,0l 179PS (Motor 930/16 mit Getriebe 915/63) - Weinrotmetallic

    944/1 Targa '84 2,5l 163PS - Platinmetallic (bis 03/2017)

  • Hello Munga.

    Sounds like the fuel pump relay to me too.

    If it is the 2.7 from the footer, I would have a look there.

    DME relays are only available with the Motronic from 1984 onwards in the 3.2.

    Greetings Stefan

    Stefan which is the fuel pump relay.... in the motorcycle the rectangular one next to the round one

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    Porsche 911 Targa Saharabeige G 2.7 November 73

    schöne Grüße

    Roman

  • Hello Roman,

    have a look here - it should be the red one in the trunk (i.e. at the front).

    Greetings Stefan

    This post has been automatically translated.

    alte Porsches:
    911S Ex US '76 mit Umbau auf 3,2l 207PS (Motor 930/21 mit Getriebe 915/68) - Silbermetallic, Schiebedach

    911SC Targa Ex US '81 3,0l 179PS (Motor 930/16 mit Getriebe 915/63) - Weinrotmetallic

    944/1 Targa '84 2,5l 163PS - Platinmetallic (bis 03/2017)

  • Hello Roman,

    have a look here - it should be the red one in the trunk (i.e. at the front).

    Greetings Stefan

    Unfortunately I don't have that.... I only have the horn relay at the front on the fuse strip..... I assume it must be the one at the back...there is only the round or the square one, one of the two.....

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    Porsche 911 Targa Saharabeige G 2.7 November 73

    schöne Grüße

    Roman

  • Something has been tinkered with on yours. In the front of the fuse box on the right, the fuse should be for the pump. -But it looks like you don't have a cable connected to it. The fuse is also wrong, it should be 25A.

    At the rear there is a cut cable behind the black relay and the cables of the round metal relay are almost connected to the rear window relay. Doesn't look good.....

    On the 77 I have here, the pump relay is definitely on socket 7 in the front fuse box,

    Apply power directly to the pump and see if it runs.

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  • Oh yes, if you don't want to go under the car, the pump cable comes up in the trunk in the middle behind the tank. Simply follow where it goes to the box. It is black and brown. Black is plus.

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  • Something has been tinkered with on yours. In the front of the fuse box on the right, the fuse should be for the pump. -But it looks like you don't have a cable connected to it. The fuse is also wrong, it should be 25A.

    At the rear there is a cut cable behind the black relay and the cables of the round metal relay are almost connected to the rear window relay. Doesn't look good.....

    On the 77 I have here, the pump relay is definitely on socket 7 in the front fuse box,

    Apply power directly to the pump and see if it runs.

    Sorry, everything fits.... has been running exactly like this for 3 years .....

    Incidentally, this morning after a night's rest, just like yesterday.... the pump starts up again when the ignition is switched on

    This post has been automatically translated.

    Porsche 911 Targa Saharabeige G 2.7 November 73

    schöne Grüße

    Roman