An odd problem

[marco pabst]

Ok, so I just got my new top on the cabby and its time to get it on the road after a whole year of working on it. the engine runs fine, transmission shifts, but, while I am going down the road the car will simply die. at first we thought is was the fuel pump relay since we could hear it going off so, we wired it straight to the ignition switch. but then when I got to the pump to put gas in it. it would not turn off. sooo, I filled up anyway and went to drive off and it died again. so I cranked it and it started right up. moved 100 feet and died again. cranked right up and again and again, and again, and the it went the rest of the way home no problem. my grandfather (who has worked on vws for the the past 30 years or so and I decided it was either : the ignition switch being faulty, the fuse box, or the ecu for the cis system( sorry im not sure what it is called but its the little thing on the upper right side of the engine bay). I am posting to see if someone can come up with something we may have missed.

any ideas? also sorry about the grammar its been a long day.

[Briano1234]

what year of cabby?

As the ecu in the rain tray says it is a digifant or 90...

Wiring the fuel pump to the ignition switch is a bad idea. If you can hear the pump then either the main pump or hte in-tank pump is bad.
I would start with a new fuel pump relay, and replace the in-tank pump.

[CalAltaDubber]

Marco, I'm not quite sure that I fully understand you.

First off, I would agree with Brian to check the fuel pump located in the fuel tank (Fuel Transfer Pump). They are easy to swap out, so it's worth a look. Besides, they have been known to fail.

Depending on the year of your car the fuel system is either CIS or Digifant. CIS is a mechanical system and doesn't have an ECU per se. So if your car is CIS, I would tend to try the fuel pump relay as the second place to look.

Since the relay is mounted on the fuse panel, you should be able to see if there is any corrosion that might contribute to the problem.

Finally, it never hurts to replace the fuel filter with a new one.

[marco pabst]

So since my car is right now in another state I asked my dad if he could check on the in tank fuel pump. turns out the wires going to it were broken off. He was nice enough to fix them earlier this week and now that I am back in town we tested it out. I drove around for about half an hour, stopped and started several times, no problems whatsoever. Tomorrow I am going to drive it some more just to make sure its ok.

also, I have an 87 model cabriolet for you who were asking so, technically I don't have an ecu.