Stalls and hesitates after warm up

Tiny
LFERGU
  • MEMBER
  • 1990 VOLKSWAGEN RABBIT
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 213,000 MILES
Engine runs fine till it gets up to full operating temp. Then it starts to bog down and black smoke starts to come out of exhaust. I can unplug the fuel pressure valve along with the temprature sensor (the blue sensor) and the car runs fine. I plug either one back in and it will die. I have replaced fuel pump, fuel filter, blue temp. Sensor, checked for vacuum leaks. Any ideas would be appreciated.
Wednesday, October 14th, 2009 AT 12:58 PM

1 Reply

Tiny
BORIS K
  • MECHANIC
  • 836 POSTS
Hello

Your vehicle is equipped with the Digifant 2 fuel injection system.

I would suggest to carry out a fuel pressure test first
Connect a suitable fuel pressure gauge to the check port at the fuel rail.
Please see second picture below
At idle we should see a pressure of 2.5 bar and with the vacuum line disconnected at the regulator we should see pressure of 3 bar.

Please take care when disconnecting the fuel lines as the will be under pressure

How to test fuel pressure on VW Digifant system.
https://youtu.be/qp8gcQSKlwQ

Please see picture below of fuel rail and inspection port.

Please let us know how you get along.

Cheers, Boris
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Monday, December 6th, 2021 AT 3:13 AM

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