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I have a slow leak in my fuel circuit. It's coming from this device:



What is it?

This view is from the passenger side, looking toward the driver side, from in front of the rear wheel.

It looks like a fuel pump, and it's got a red wire and a green wire running to it. I have not verified where these wires go.

It's located on the passenger side, in front of the transaxle, opposite and little back from the charcoal cannister. It's got a fuel hose going to it that comes from the hard fuel lines from the front of the car. This hose hooks up to the inlet on the passenger side of the device. On the driver side is an identical outlet, which connects to a hose that hugs the pan and runs to the 1 and 2 cylinders' fuel injector rail. It seems to be leaking from seals in its body.

I can't find one of these in any VW manual, and it doesn't have a VW logo on it, like all of my parts do.

While I'm on the subject of 411 mysteries, let me ask another question. I've got a bundle of wires under the driver seat. They are sleeved together until the last 8 or 10 inches. One is green and loose, one is yellow and with a red stripe and loose, one is brown and grounded to the negative terminal of the battery, and one is brown with a white stripe and grounded to the floor pan with a screw. Anybody know where these loose ones go?

-Cale

That is the heater fuel pump in the background. It may be a fuel pump...but my bet is that it is a fuel filter...with a warning light like you use on a diesel. Trace the wires with a voltmeter.

I am going from memory here...but I beleive that the brown and white wire screwed to the pan is either the ground for the lights in the shifter housing if you have an automatic....or is the ground for the seat belt warning switch. Both of the brown wires are grounds and belong to one or the other systems. Also.....check just to be sure...but one of those grounds may also go to the drivers side heater lever switch and is related to the auxiliary inline fan for the heater system. The green one may be part of this as well. Green is generally power.....its like an olive green...right?

The yellow with red stripe....took me years to figure out. It went to a float switch mounted in all original equipment VW batteries. It signaled that battery fluid was low....isn't that cool? Ray

I'm going to take that mystery object out to dissect it. I can't have a fuel leak. I just heard through my yahoo group about a guy whose bus burned to the ground because he didn't maintain his fuel lines well enough. Poor dude. I don't want that to be me.

Ray, my shift lever light up display is working perfectly, so I assume that's grounded properly. I'll hook the green one up and see if the fan kicks in. And, of course, without an OE battery, the striped wire is useless. As long as it's not an issue, I will leave it tucked under the carpet.

Thanks for the help! If anybody else knows what that unidentifiable piece of equipment is, let me know.

-Cale

From the shape of the bottom of your object it looks to me like it contains a motor, that would make it a fuel pump as per my wild guess. Do you have a pump somewhere else? The original pump was up front right behind the tank.

If you replace the fuel lines, please remember that all lines from the pump, through the fuel loop, and to the regulator must be fuel injection rated. You should also use the correct clamps for use with fuel injection. To help stop siphoning in case of a fire that burns through your fuel lines adding one of these Series 100's near the tank will stop fuel flow. It should be set around 20 inches of water.

http://www.smartproducts.com/check_valves.php

Yes, I have a working pump under the tank, and yes all fuel lines on my car are FI rated, as are the clamps.

If nobody easily recognizes this thing, it might not be a VW part.

Perhaps my fuel pump stopped working long ago and some previous owner disconnected it and installed a secondary one here. Then, when the last owner of the car obtained it, he tried to get it running and hooked up the old fuel pump again. Now I've got them both: the old one I got working, and the new one leaking.

Somebody please disprove this theory and tell me what I've got is a valuable component to my car.

-Cale

The thing looks more like a fuel filter than a pump to me, does it make noise or vibrate when running the car?

The wires should be one of those connected the test plug (VW diagnos), didn't know that was introduced until -73, but maybe the harness is from a newer car.
The two wires carrying brown color indicates the voltage drop from the battery pole to the chassi. The red indicates the voltage at the positive pole. The green one is unknown to me.

Since the VW diagnos ist just a monitoring system (not in use any more) it does not matter if the wires are connected or not. I have used them to carry oil temp and oil pressor sensor signals from the engine compartment (where the test plug is) in to the coupe for further transmission to the meters at the dash, saving me from having to find a way to the engine compartment.


/Lars

hy,,have you look if you have the gaz pump in the front ,, if not ,,the guy transfert the gaz pump in the rear for to stop ,, the hard start ,, vapor accumulation ,, during the hot weather,,and the 2 hoses comme from the front gaz tank,, that is a possibility,,

hy,,have you look if you have the gaz pump in the front ,, if not ,,the guy transfert the gaz pump in the rear for to stop ,, the hard start ,, vapor accumulation ,, during the hot weather,,and the 2 hoses comme from the front gaz tank,, that is a possibility,,