Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: gorgoo on May 08, 2017, 21:26:52

Title: Inverted fuel pump
Post by: gorgoo on May 08, 2017, 21:26:52
Hello,

My car is nearing the end of its lengthy restoration and I've had a strange thing when re-starting the engine after 6 1/2 years: no fuel pressure.
Fuel pump was running, there was petrol in the tank, but nothing arrived, no pressure in the engine bay.
I inverted the wires at the pump, thinkig it may help to prime it and bingo: there was fuel in the engine bay.
But after reverting to the corect electrical feed (plus from vh on the plus shown on the pump) still no pressure.
When I got the car, pump was normally plugged, with "+ wire" connected to "+" port of the pump.

It now runs, still with the pump plugged with the "+" wire on its "- " terminal.
Could anyone explain that?

Didier.
Title: Re: Inverted fuel pump
Post by: GGR on May 09, 2017, 05:24:21
En effet, plutot renversant...
Title: Re: Inverted fuel pump
Post by: Tyler S on May 09, 2017, 13:30:35
If/When the pump was rebuilt, the permanent magnet housing was installed 180 degrees out. You can disassemble the pump and correct the housing. Its the top part of the pump that looks like a can.
Title: Re: Inverted fuel pump
Post by: Shvegel on May 10, 2017, 02:58:26
Wow! good call. 
Title: Re: Inverted fuel pump
Post by: ejboyd5 on May 10, 2017, 11:54:36
Pump runs either direction depending on connection polarity.  An old trick to try and clear an inoperative pump was to run it in "reverse" to rid it of clogs.
Title: Re: Inverted fuel pump
Post by: BaronYoungman on May 10, 2017, 16:18:29
wont hurt anything but either the "can" was put on backwards, or the plastic connector leads were reversed. What side is the red "+" tab on?
Bob
Title: Re: Inverted fuel pump
Post by: gorgoo on May 10, 2017, 17:55:02
Hello,

And thanks a lot for these advices. Must be the magnet as I didn't dismantle the plastic tabs.
That one should not be too complex to sort out  :)
Didier

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