Questions and Answers

Volkswagen Fox Fuel Delivery Problems Q. 1989 Volkswagen Fox. I am having trouble finding where the vacuum line from the pressure regulator connects to the air filter? I've looked down under the filter box and can not find where it connects! Could you help me find it? Also, on the fuel distributor box, it seems to be missing the "anti-tampering" plug. Would this keep the car from running?

I have replaced the fuel tank, the fuel pump in the tank, the fuel filter and took your advice on checking to see if the reason the car will not start is due to "fuel" or "electrical," and the car ran when I sprayed carburetor cleaner into the fuel distributor box. Hope you can help me out. I hate to put the Fox in the grave just yet.

Have a good day,
Gary
Cartersville, Ga

A. When you say "pressure regulator" I'm assuming you are referring to the fuel pressure regulator, in that case this device is operated by direct manifold vacuum, it should have a vacuum port located directly on the intake manifold.

The anti-tampering plug on the fuel distributor being missing won't prevent the car from running unless someone tampered with the CO adjustment it covers, too much.

Now that you've replaced the fuel pump you still need to verify the presence of fuel pressure to the injectors. A simple test is to pull one of the injectors out of the cylinder head, turn the key on and manually actuate the airflow sensor plate. You should observe fuel spraying from the injector if pressure is present and the injector is good.

If you don't get a spray, verify your fuel pump has pressure at all utilizing a pressure gauge capable of up to 125 PSI minimum tee'd into the cold start injector feed tube. Crank the engine and observe the pressure reading, it should be an instantaneous 100 PSI, (after you get your fuel pressure regulator connected).

If not, check the fuse and fuel pump relay, and you can also verify actual operation of the fuel pump by listening close to the fuel tank and having an assistant crank the motor.