Best way to replace 2nd fuel pump?

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Mon, 24/08/2015 - 04:52
rkl786
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I am planning to replace the fuel filter and fuel pump on a 1991 463 230ge model G wagen. I know the second fuel pump and filter are behind the left tire, I just want to know what would be the easiest way to get to them to replace the parts. Also I am planning to only replace one fuel pump right now, would it be better to replace the pump next to the filter or the one under the gas tank? thank you,
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Mon, 24/08/2015 - 21:04
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Arnie
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Re: Best way to replace 2nd fuel pump?

Best access is to remove the rear, left wheel, and then the plastic wheel-arch liner (about 10 screws). You will see the pump and filter under there, suspended on a cradle by a set of rubber rings. Release the assembly and lower it down, and then you can disconnect the relevant electric cable and hoses.  You can get the correct Bosch fuel-pump, including the one-way valve, for about GBP £70 from an number of on-line spares retailers.

For safety, disconnect car battery before starting this job and take care when working on the fuel hoses.

is there a reason why you wish to replace just one pump? if the car is difficult to start, but runs well when started, you should check the fuel accumulator (next to the filter and pump) and the one-way valve on the pump.

The KE Jetronic (fuel injection system) requires the combined pressure and flow from the two pumps for the engine to develop full power.

Alternatively, a single, new-type, high-pressure pump may possibly be substituted (below the tank) for the two standard pumps.

 

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Tue, 25/08/2015 - 02:59
#2
rkl786
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Re: Best way to replace 2nd fuel pump?
Thank you for the information. Was going to do the single high-pressure pump. I will look at the fuel accumulator as well. The G right now does have trouble starting but drives well. My goal is to get the Gwagen starting right away at the twist of the key.
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Tue, 25/08/2015 - 10:19
#3
Arnie
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Re: Best way to replace 2nd fuel pump?

If you are going for a single- high-pressure pump, that should be installed at the bottom of the tank.

HOWEVER, I think your starting problem is not related to the fuel pumps.

First check the fuel accumulator, which is supposed to hold pressure when the engine is turned off.

Then, check the one-way valve on the pump, which works with the fuel accumulator to hold the pressure and prevent fuel back-flow to the tank.

I think your problem is with one or both of these items and NOT the fuel pumps.

The fuel accumulator can be checked easily, by disconnecting its rubber return hose to the tank. If the internal diaphragm is damaged, you will see fuel coming out of the return line when the engine is started.

The fuel accumulator helps engine starting with a hot or warm engine, but makes little difference to a cold engine.

If your engine takes a long time to start both when it is hot and when it is cold, the most likely fault is the one-way valve on the end of the fuel pump, which is about Euro-10 to replace.

Also, I would change the fuel filter.

 

 

 

 

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