Starting problem 2003 VW Jetta - Thoughts?

[Begester]

Im trying to figure out the reason why my wife's 2003 Jetta wont start..at first I thought it was the fuel pump, but when I cycle the ignition, I can hear the winding up of the pump, so I've ruled that out. I'm now moving toward the "spark" question and am going to replace the plugs/wires over the weekend, but has anyone ever heard of plugs being so bad that the car wont start? The car has 103,000 miles on it and the plugs have never been changed.

I took it to Auto Zone last night and got 7 error codes pop up, each cylinder is reading a low fuel mixture (4 codes), and I'm told that injector cleaner might help that. I also got an O2 sensor error.

The battery was dead (partially because I drained it while trying to start it), but when I jumped it, the car started right up and ran fine. I put the injector cleaner in and drove about 20 miles, car ran great. Got home and tried to restart it, and it started right up..then came back 20 minutes later and the car just cranked and cranked but wouldnt turnover.

Any suggestions?

 

[ufm82]

Re: Starting problem 2003 VW Jetta - Thoughts?

1) Even though you hear the fuel pump run, is it providing pressure? There should be a valve somewhere on the fuel rail/fuel line that will allow you to tap in and check fuel pressure. Perhaps the pump is running but is failing to provide either pressure or volume. Cycle the key, listen for the pump noise and open the valve- fuel should squirt out. That will at least tell you that you have fuel. A gauge will be needed to check pressure.
2) You need to check it when it won't start. Do you know how to check for spark? When it won't start disconnect a plug wire if possible and use a spark tester- see if there is spark and if it will jump a gap.
3) Don't start throwing parts at it until you know what is wrong. It's a waste of money and time. The codes tell you that you have a lack of fuel. ( never heard that description though) Fuel filter would be my first "part" since it is cheap and easy to change. Then check your pressure/volume. Once you know fuel is not an issue move on to something else.