Hey guys - I’m trying to troubleshoot my wife’s 2003 VW Jetta 1.8t.
We’ve had the car fail to start three times and die randomly on the highway once. All but one of those times were we able to get the car restarted within 5-10 min after cranking the engine multiple times (engine is turning over fine when cranking)
So here is what I know so far:
-ALL of the issues have been experienced with a 1/4 of a tank of gas or less. (tank has never run dry)
-Fuel Pump under rear seat seems to be louder than normal and makes different pitched noises when idling. (I can faintly hear the pump running at driving speed)
-Turning the key to the on position sometimes and sometimes does not prime the system.
-When I put my finger on the fuel pump relay and turn the key to the on position I will sometimes feel the switch turn on for 2 seconds and other times not. Almost every time I feel the relay switch come on so does the pump… except twice i’ve felt a one second delay where the relay clicks on but the pump doesn’t run until a second later.
- Even when the fuel pump doesn’t prime, the car will usually start and run. Pump starts once there are RPM’s
I’m not a big fan of swapping parts but rather troubleshoot first. So my questions are…
If i’m hearing the fuel pump prime sporadically is there something in the system that tells the relay to not kick on if there is already enough pressure in the system? Should I start with replacing the relay, pump or car battery? (I’ve already cleaned the battery terminals which had some corrosion.) Thank you!
FYI - Over 160K miles with original relay and pump.