No Start

[Osmosis]

My wife drove my A6 home last night and parked it in the garage as normal. The car has under 1/4 tank and half way between the red on E and 1/4 mark. I've driven this car on the red E before with no problems. Today, we went out to start the car and it sputtered and died which it never gives me any grief. I tried to start it again and it started for a few seconds, died. Everytime I put my foot on the throttle, the car sputtered and died. I wondered if my fuel gauge was going out? I added some cheap 87 fuel to it, it sputtered and died a few more times. I ran my code scan via torque pro to find no codes other than my deleted combi valves. After I had reset my APR tune a few times, with unsuccessful restarts, the car finally started again. I let it idle for about one minute. When I pushed on the throttle, the car had a noticeable sputter from idle to 1200 rpms. I revved it up to 5K a few times and once the rpms got beyond 1200, no problem. The car then idled and ran fine. I let it cool down, started like nothing was wrong. After I had added the fuel, fuel gauge is now reading above 1/4 tank. I was showing no codes and as far as I was concerned, it was most likely a fuel problem, low fuel.

Well, this morning, I go to start my car fully expecting it to start up and when I turned the key......it sputtered for 10 seconds and died multiple times...again . I pulled off the gas cap just incase it was some sort of funky air in the tank and the car tried to start. I started the car about 5 more times before it would hold idle. Finally, the car was running at idle and i stepped on the throttle, the car would die. Then it would sputter from idle to 1200 once I got it started. Then If I pushed on the throttle the revs would sputter up to 1200 and then rev up normally to 3-5K rpms. Once I got it to idle, I then drove it down the street and it drives like nothing is wrong??? WTH???


Help, please

[Alex JB]

It may be worth putting a multi meter on the battery and read it while it’s cranking and spluttering, drooping voltage on my bike does something like this.


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[Osmosis]

I waited about 45 minutes and the car starts up like there has never been a problem. No sputter from idle to 1200 rpm's, no codes, nothing??? I drove it around the block and jumped on the throttle, accelerates like it always does, quick and snappy throttle repose as normal.

I've no idea. Seems like when it's cold, it starts for a few seconds and dies. When it's cold, each time I start the car, it runs for a few seconds, sputters and ides. Then, once I touch the throttle, the car immediately dies. Seems like after multiple starts, once the car holds idle for a minute, I punch the throttle and it sputters up to 1200, then rev's past the sputtering mark, 1200rpm's, and it revs as high as I wish. Once it warms up, the car drives as if nothing is wrong?

[mr_dave]

Clogged fuel filter? Bad fuel pump or related electronics?

[Osmosis]

Only does it when it's cold. At first, I suspected the fuel pump. The way it starts in the morning with the surge. Once it warms up, it's completely resolved. I even jumped on the throttle once it got running and the car accelerated like normal. One would think a clogged FP would have some consistent hesitation. It's been 3 hrs since I last started it and it starts like there is nothing wrong. I will be trying again in the morning :(

[Osmosis]

Well, My volts are a sold 14.1v, cranking drops to 12.5 and back up to 14 as she starts up.

I have been searching for hours. I put vacuum to the fpr and it holds vacuum. I put the vacuum pump to the hose that feeds to the fpr and there is no vacuum, I think this is normal for this hose?

I looked into putting a gauge to the fuel line, but there is no schrader valve to hook my fuel pressure gauge to the line.

I disconnected my ECU and cleaned the terminals.

Checked fuel pump fuse which was good.

So, how does one check the fuel pressure on our cars? My torque pro does not have a way of reading the fuel pressure that I am aware of.
And what is the best way to check the fuel pump? Not sure it's the pump as it only acts up when it's cold or has sat for over 4 hours. Once the car is warm, runs fine. No codes either :( I also hooked up vag com light and showed no codes.

[Osmosis]

Well, she sat all night long and the car is doing the exact same thing. Car fires up for 2-5 seconds and then dies after it has sat all night long. Once I turn the car over with multiple starts,it sputters and dies, then it finally holds idle. Once it warms up after say...2 minutes, the problem is gone and the car starts like there was never a problem. WTF?

A few thoughts, bad fuel? I put 87 in because it was the only fuel offered at the station and I was almost on E. I put 5 gallons in. I considered putting a 5 gallon of 92 with some fuel stabilizer, but I don't want to have to pull the tank with 5 extra gallons in it if it is the fuel pump. That being said, How do I check the fuel pump?

How do you test the fuel pump relay?

I tried to connect via VCDS. I have the light version and it would not allow me to read the fuel pressure :(
I Put a vacuum gauge to the fuel pressure regulator and the car had no change to it upon start up. I put zero and 20mm/hg vacuum to the regulator with no change either way. Car just sputtered and died.

Now, how to test the fuel pump?


Thank you guys for the help.!!!

[Osmosis]

Checked fuses & all are fine. Power goes on to fuse 28 when key is turned. I found the fuel pump behind the rear seat. I put 12v to the pump and grounded the other side. Pump makes no sound?

[m_haiser]

sure sounds like a bad fuel pump. far more likely than bad gas. even with bad gas it would run

[Osmosis]

SO, I put my multi meter on the pig tail and then attempted to turn the car on. *While cranking the engine over, no power was at the pigtail that connects to the fuel pump.

​​​​​​​What now???

[m_haiser]

fuel pump relay?

[Osmosis]

So guess what sensor popped up on my torque app?

​​​​​​​CTS!