Brian Harwood

My car 2001 S8 D2 . 161716 miles. It cranks fine.

I hooked up VAG-COM and the engine has no codes. The airbag has six.

If let it sit for several days it fires right up. It has done this twice. Fortunately I have other cars to drive.

I drive it around for 10 minutes come back to my garage, shut it off and now it will crank fine and won't start. When its running it runs like a beast.

Tank is 3/4 full. It got a new timing belt/thermostat about 600 miles ago. I got new keys and two HVAC blending doors replaced at the Audi stealership about 100 miles ago. The airbag light started coming on not long after that and its throwing several codes for that. That airbag light started out flickering but finally is now on strong.

Any ideas what to check now? Relay/Pump etc...how to test or is there some typical cause when this happens that doesn't throw a code?

Thanks!
Brian

silverd2

Fuel pump... they always fail eventually and throw no codes.

audinutt

it could be a faulty crank position sensor, but it's hard to say, could be fuel pump as well

Y888

Take out the fuel filter under passanger side in front of rear wheel and check the date on it,probably has never been changed.Mine was cpo and dealer maintained and never changed fuel filter lol .Thats why my pump died.New pump has to be seated correctly in order to work properly.
Set of gaskets for the assembly so you dont have to buy whole assembly from the dealer for 900$+

https://www.europaparts.com/fuel-pum...slUaAotS8P8HAQ

https://www.ecstuning.com/b-genuine-...ly/4d0298087b/

https://www.europaparts.com/fuel-tan...d0298133c.html

jfrahm

CPS can be seen in VCDS, engine speed can be read. If it's the fuel pump a puff of starting fluid should cause it to catch briefly.

the_duke

Good advice here.

SSSS8

I had a engine coolant temp sensor fail and my car would not start when it was cold. On the other hand if you need a fuel pump I have one out of my car that is know good I will sell cheep.