so some weird issues I'm having with my B6, the car takes several cranks to turn over, this issue started with me being unable to fill the car with fuel without having to pull the fuel nozzle out to relieve pressure, you could hear the pressure release when i did this.

as of now i have replaced several parts and i still have to crank the car multiple times, it has a slight backfire then will start on the next crank, the car runs well once it is running but it can't start on the first crank ever, even after just shutting it down it takes 2-3 cranks to start.

Replaced:
Fuel Pump
Fuel Filter
Fuel Suction Jet Pump ( AWD)
N80 Evap Purge Valve
Spark Plugs

Edit:
Check Valve next to N80 valve
Charcoal Canister


The Car does have CEL but i have been unable to read it and 2 shops have been unable to diagnose whats is wrong, the OBD2 port is getting power but that seems to be it.

is there anything that sticks out that i can test?

thanks in advance.

 

The pressure build-up while filling seems like a fuel station equipment problem, rather than your car. Around here anyway, there is always a vapor recovery path included with the gas station's hose.

If still hard to start without a trip to the gas station, several common things can cause that. Number one is often the coolant temperature sensor (CTS), which when faulty will tell the ECU that the coolant is, for instance, very cold when the coolant is actually hot. The result in that case is the fuel mixture being too rich to light. Another very common reason is an air leak, which sometimes takes a smoke test to locate. At least start by inspecting every vacuum hose and check valve for problems.

Before going too much farther, I would try to (unsuccessfully, on purpose) start the engine, then immediately remove the spark plugs for a look and sniff with your nose. If sooty or smelling like gas, then too much fuel, which could be the CTS or non-firing spark plugs. If dry and no or little fuel smell, either the injectors not operating, the CTS is faulty, or an air leak. Other things that can cause hard starting are crank and cam position sensors, but you'll need to get the OBD scanner to work first.

An A4 with everything working normally should start immediately. My old '05 3.0 with 215,000 miles starts in about 1/2 second, hot or cold.

 

so i hadn't filled up since replacing the charcoal canister, that has resolved the filling issue, however I still have hard starts.

the CTS was replaced to a green top one 50k ~ ago, i will try the spark plug thing when i get home.

 

If still hard to start without a trip to the gas station, several common things can cause that. Number one is often the coolant temperature sensor (CTS), which when faulty will tell the ECU that the coolant is, for instance, very cold when the coolant is actually hot. The result in that case is the fuel mixture being too rich to light. Another very common reason is an air leak, which sometimes takes a smoke test to locate. At least start by inspecting every vacuum hose and check valve for problems.

 

My 2003 a4b6 Alt engine was getting harder to start, then a check engine light came on, it was for the camshaft sensor. I replaced that, 2 screws, 2 torx & 2 hex head screws ( Audi!) and NZ$65 and that fixed it.
​​​it.I think that the P code won't come up for a while after that sensor has started to go bad, so the symptoms appear first, then the code appears occasionally, then frequently.
it's a easy fix but be very careful not to drop any of the bolts down into the cambelt area. Like be extra careful & going as far as using some tape or something , just something, to not drop the bolts.