I used an external power to connect to the fuel pump, and it worked. I put the car connector back, had my wife crank the engine (not just the ON position), there was fuel coming out from the feed line. I then used the external power again to run the fuel pump for about 10 seconds to charge the feed line with pressure, used another car to jump (so that the battery is not a concern), it still wouldn't start. I know I have sparks, I have fuel in the feed line, I have RPM reading from the ECM, my starter cranks, the car just does not start.

Tomorrow, I will have a friend come over to gothrough the basics again just to make sure I did not make anyincorrect judgement. But I do have a question for now on the starter:

1) what is the RPM supposed to be when the starter starts the engine?
2) As far as I know, a starter does not just stop working; it should show sign of going dead but actually go dead slowly; this happened to a car I used to have. But as long as it still cranks, it is only a matter of "harder to start", right?

 

Do you by chance have a 2.8? They have issues with carbon buildup. If so attempt to start the car with the gas pedal to the floor. It may take extened cranking to get it to start. 100-200 rpmp should be plenty to get the car to start. The factp tat your getting fuel and spark is a good indication of that. If rpms arent sufficient you wont get either. You may also want to check for incorrect coolant temp sensor readings. If you have a scan tool your can compare the coolant temp to the air temp to see if they are reading correctly.

 

Thanks Dankhound. Problem solved. Mine is a 99 A6 2.8. I made a wrong judgement on the spark plug when this issue first came up. It is actually wet instead of dry. I guess the tip of the spark plug will always be dry; the thread area is wet I later realized.

I did what you said, gas pedal to the floor, the second attempt the car started and lots of smoke came out. What happened before this issue was that the morning before I started the car, the engine went to high RPM, I moved the car from my drive way to my garage, and shut it off while the engine was still in high RPM. The whole processlasted about 10 seconds, and I think that'show I flooded the engine.

Dankhound, you said the carbon buildup, I used SeaFoam 2wks ago, it is supposed to remove the carbon build up, or is it? And did you mean the carbon buildup at fuel injector so it does not close well causing the engine flooded?

Also, thanks a lot to Jeffla and AudiTech79 for providing valuable advises that helped me to identify the root cause!

 

nevermind