Fuel Pump Question - 93 Volkswagen Fox...

I know this is a BMW newsgroup, but I am desparate for help.
The VW has an electric pump external to the the tank My friends car will run poorly, then die, then start back up.
A mobile mechanic did a very quick check and said the fuel pump was bad. He did not use an electric meter to test any resistances and I am wandering if maybe he was a little too quick in his diagnosis, to make his $40 easily without getting his hands dirty.
I am wondering if the electric connections could be dirty. Or maybe it is just the fuel filter.
I am wondering how could he really know the electric pump is bad, without an ohm reading???????
Thanks in advance for any help.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Experience maybe?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

will
is
without
-----
Just look it up on advanceautoparts.com and click on "see all vehicles this part fits". Use that info and check the local breakers/junk yard. Get one cheap. Check it out.
What happened to common sense when researching parts? Oh, yeah, and using the corret group??? The internet makes this crap so easy, as opposed to 10 years ago when you had to visit the parts shop.
Bill in Omaha '86 535i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You can jumper the fuel pump fuse to a constant power source. The fuel pump should run. Have an assistant crawl under to listen while you do this.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It may be the sound of the pump he was judging it by. dying/tired electric motors tend to have a sound to them. A fuel filter will not usually cause a car to die though so I think it might not be that. checking the connection is a good though. I personally would consider taking a look at ignition components might be a good idea. Easiest way to start (my opinion) buy a spark tester and have one person under the car to listen to the pump and one to watch the spark tester and see witch you loose first.
Hope this helps!
chazg32
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

JoshIII writes: Clogged filter?
Ask your friend if he ever let his tank run dry (run empty) while driving. If he did, even once, then yes its time to replace the pump and filter.
You can damage a fuel pump in less than a minute if the tank runs dry. A a fuel pump needs fuel for lubricant.
I don't know if BMW still makes a practice of this, but in my 1980 model BMW electric fuel pump, both the pump motor and pump are immersed in fuel in their hermetically sealed alumimun housing.
I would think the spark from the motor's brushes would ignite the fuel, but apparently not. Hopefully there is no oxygen in the fuel line.
JoshIII upstate south carolina josh3i at hotmail . com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Assuming there is fuel in the tank and no obvious blockages then this sounds like fuel starvation caused by a faulty fuel pump.

Fuel pumps and filters (replace at the same time) is a fairly easy DIY, but be careful having fuel and possible sparks around at the same time.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.