The ignition system on your Audi B8 controls one of the three essential functions needed for its engine to run. Failing plugs or coils will produce a weakened spark at best, resulting in poor ignition of the fuel/air mixture in the cylinder. Without the spark, the engine will make significantly less power while sounding and feeling like something just isn't right.
Even though the spark plugs and ignition coils play a critical role in how an engine performs, they are easily accessible and require a few hand tools to be replaced. The cost of parts is relatively cheap, and valuable wrench-turning experience is gained in completing it on your own.
Audi models and years applicable:
Symptoms of Audi B8 spark plugs or ignition coil failure:
- Misfiring of engine
- Reduced engine performance
- Trouble starting the vehicle
- Reduced fuel economy
- Engine backfiring
- Check engine codes
Any lack of spark can also leave raw fuel in the cylinder. The unburnt fuel can clean the cylinder walls of the thin layer of lubricating oil, potentially causing the piston rings to scratch the cylinder bores. Scored cylinder walls will lead to an excess in oil consumption, and will cost exponentially more to fix than servicing the ignition system.
A P0300-P0306 code will pop up when the engine computer determines that there is a fault with the spark in a specific cylinder.
To ensure that your ignition components are performing as they should, replace them every 100,00 miles or so. If you are pushing more power through your engine from any modifications, cut the service interval in half.
What will it cost to change the spark plugs and ignition coils on my Audi B8?
The kit we provide for this job costs just under $200. For that, you get six OE ignition coils and six NGK spark plugs. No other parts are required for this job. Completing the job yourself saves you around $100 over what a dealership will charge.
How long will it take to change the spark plugs and ignition coils on my Audi B8?
Set aside an hour to complete the job. Engine components need to be moved on either side of the engine in order to access the plugs and coils.
The air filter will be out of the car during the plug and coil replacement. This would be a great time to change out that filter as well.
Tools required to change the spark plugs and ignition coils on my Audi B8:
- 8mm Socket
- 10mm Socket
- T20 Socket
- ⅝ Spark Plug Socket
- Rachet set
- Ratchet Extensions
- Flathead Screwdriver
- Torque Wrench
- Wire Cutters
Parts required to change the spark plugs and ignition coils on my Audi B8:
Steps required to change the spark plugs and ignition coils on my Audi B8:
Step 1: Remove the intake system
Start by opening the hood and removing the rear section of the engine cover. Grip the cover on both sides and pull it up. Be careful when removing, the cover requires a firm pull but is made of plastic.
The clamp used to connect the factory intake tube to the throttle body requires a 7mm socket; however, the aftermarket intake on the S4 in the video requires an 8mm socket. The clamp retaining the intake tube to the air box or air filter should be the same size as the first clamp.
If you have the stock intake, use a flathead screwdriver to remove the retaining clips out of the top radiator shroud and then pull the covering off. Next, use a socket and remove the two fasteners securing the intake snorkel to the radiator support. Then, grab the airbox and wiggle it up and out of the engine bay. An air hose connects to the bottom of the box near the fender. Pinch it and pull it down to remove it.
Unclip the two lines from their clips on the intake tube and pull off the one line connected directly to it. Then, wiggle the tube off of the throttle body and remove it from the engine bay.
If you are using an aftermarket intake, loosen the clamps for the air filter and the throttle body. Then pull the line off of the intake tube.
Next, remove the air filter from the intake tube and then the intake tube from the throttle body. Pull the aftermarket filter shield out of the way as well.
Step 2: Remove the bank 1 ignition components
Starting with the ignition coil harness, remove the two T20 fasteners the secure it to the valve cover. Next, use the pick tool to pry up and back on the ignition coil harness plugs to remove the from the coils. Pull the harness off of the coils after the plugs have all been unclipped.
Next, use a flathead screwdriver or a plastic trim tool to gently pry up on the ignition coils to release some of their tension on the spark plugs. Finish pulling them off by hand.
Check for any signs of oil inside the spark plug tubes now that the ignition coils have been removed. The valve cover gasket will need to be changed if any oil is found inside the tubes.
Step 3: Change the bank 1 spark plugs
Use a ⅝ spark plug socket on an extension to remove the plugs from the cylinders. Always remove the plugs by hand as power tools have a higher chance of stripping the plug.
Insert the new plugs into the spark plug socket and install them into the cylinder head. Once they’ve all been tightened by hand, torque the plugs to 35Nm.
Sit the new ignition coils into the spark plug tubes and connect the ignition coil harness. Fully seat the coils onto the plugs after the harness had been attached. Reinstall the two T20 fasteners to resecure the harness to the valve cover.
Step 4: Reinstall the intake
Follow the steps from step 1, in reverse order, to reinstall whichever intake system is on your vehicle.
Step 5: Move the coolant expansion tank
Open the cap on the expansion tank until you hear the pressure release from within the tank. Unscrew the cap fully and then reinstall it if you can’t hear it release. Next, remove the two 10mm nuts that secure the expansion tank to the strut tower.
Unclip the sensor at the bottom of the tank on the right side, by the ABS module. Then, lift the tank off of the two studs and out of the locating grommet on the bottom.
Step 6: Replace the bank 2 spark plugs and ignition coils
Refer back to steps two and three to replace the spark plugs and ignition coils on bank two. The entire process is the same. Refit the coolant expansion tank, after the ignition components have been replaced, in the reverse order, they were removed.
Lastly, reinstall the rear engine cover.
Now your Audi is back to full health, and you can get back to driving without any worries. If you’re interested in more DIYs for your Audi, you can visit audi.fcpeuro.com and subscribe to our YouTube channel.