Car turns right over, sometimes it will start, sometimes it won't?

Tiny
TOMKTH75
  • MEMBER
  • 2002 VOLKSWAGEN JETTA
  • 4 CYL
  • TURBO
  • AUTOMATIC
  • 90,000 MILES
Car turns right over, sometimes it will start, sometimes it won't. When the car won't start, the fuel pump fuse is inactive. When the car runs, the fuel pump fuse is active. Cleaned the fuse box and changed the fuel pump fuse with same results. Could it be electrical or the fuel pump?
Sunday, September 28th, 2014 AT 5:45 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If there is no power to the fuse, it almost sounds like there is an auto shut down (ASD) relay or switch that is turning things off. I assume that there is no power to the fuse itself when this happens, correct? Also, have any lights come on when this happens? One other thing. When you have no power to the fuse, are you getting spark to the plugs?
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Sunday, September 28th, 2014 AT 7:11 PM
Tiny
TOMKTH75
  • MEMBER
  • 4 POSTS
Where is the port located to test the fuel pump pressure?
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Wednesday, October 1st, 2014 AT 3:08 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
It has to be tested at the fuel filter.
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Wednesday, October 1st, 2014 AT 5:59 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
You can check for pressure & flow at the injector rail.

Either the fuel pump relay is acting up, the crank sensor is acting up or the ECM Power Supply relay is acting up. Could be other things as well.

Scan the ECM for fault codes first.

Thomas
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Saturday, October 4th, 2014 AT 11:27 PM

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