ddillenger

CKP=Crank position sensor

mmasner

Hi, Replaced the CTS, still no start, just cranks but won't catch. Ran another VCDS full scan, no faults. Please let me know how I check if the fuel pump is priming, I thought the car had to turning for the pump to prime. Also, would it throw a code if it was the Crank Position Sensor? Thanks.

awdjunkies

You say potato, I say Potato lol

Sgt G

Typically you can hear the pump prime itself when you turn key til dash lights up and listen for a quick 'HUMMM' type sound coming from area where pump is located (from the rear). From the drivers seat it can be heard generally over your right shoulder( especially if you dont have background noise) and the sound is roughly 2 seconds in length before it stops.

Of course another way is disconnecting any part of fuel line -post pump- (any part running towards engine that's pressurized) and fuel should spray from disconnected/open line when key is turned to on position or while cranking (the condition u have now). On most cars you can disconnect or slightly open the banjo fitting from the fuel rail (the aluminum line fuel injectors are connected to) and check for pressure there (this how dealerships do it by connecting gauges, meters, etc). Turn key / crank engine & fuel sprays from disconnected / open fitting. If no fuel comes out, or you can't hear the pump prime itself, and you already check the appropriate fuse; then there's a problem and it's almost always the pump.

P4Ring

Whenever an engine wont start, i usually check in the following order.

1. Scan ECU for fault code(s).
2. Fuel delivery. Disconnect fuel line and check for fuel coming out...either when pump is priming or while cranking. Never rule out a clogged fuel filter, if no fuel, change fuel filter first or check for the presence of fuel before it.
3. Spark. there are testers that can go between the coil pack and the spark plug.
4. Air blockage or vacuum leak.
4. Timing..The detection process is controlled by the cam position sensor
The sensors themselves are highly reliable (hall effect switch). Mechanical timing is what usually cause them to give incorrect reading.

Petethepug

Just went through what you were describing. Internment no start and internment stall when car was at speed. NO CODES thrown except when it was having the no start issue. Don't remember the code that the tech found but it seemed unrelated to the crank position sensor. It was the the CPS

mmasner

Thanks for all the advice, really appreciate it. I'm pretty sure it's the fuel pump, there was no priming when ignition is on or when cranking. I removed the pump and waiting for a replacement which should be here by Tues. Also, Petetheplug, I never experience any stalling, just trouble starting for a couple weeks, then no start at all, but I appreciate the advice. I'll have the Fuel Pump installed by Tues and will update all. I did have about half a tank and it still dumped a bit of fuel on the garage floor, recommend making sure the level is close to empty, had to siphon.

mmasner

Hi Everyone. Well I finished the new fuel pump installation and the Allroad started right up. The installation took me about 3 hours total and was quite simple, I followed the tutorial posted on the AudiWorld website (link below) and had no problems. Make sure you have an almost empty fuel tank or else you'll have to clean up fuel, like I did.

To give a quick recap, I had intermittent starting issues, the Allroad would crank for a few seconds before catching, then run fine. About two weeks after the issue I had a complete no start. I ran a full VCDS scan but only had o2 sensor error codes, which wouldn't cause a no start. I checked all fuses and battery power, they were fine. I replaced the Coolant Temperature Sensor but that didn't fix the issue. I removed the rear seat and couldn't hear the fuel pump priming. I replaced the fuel pump and now the Allroad runs great.

I wanted to thank everyone who responded for your help, couldn't have done it without you guys giving me solid advice. I really appreciate it and probably saved about $400 fixing it myself. Thank you.

https://www.audiworld.com/tech/eng.html (link to DIY Allroad fuel pump)