For those who are unaware, the high pressure fuel pump creates fuel pressure off the camshaft lobe. Everytime the cam spins, it causes the hpfp spring to push in and out, creating a metric shit-ton of fuel pressure as required for direct injection. The cam follower is the mediary between the hpfp spring and the camshaft.
TOTAL TIME: 30 - 45 minutes
PARTS
You will need a new cam follower listed here , I went with the INA follower. Although not required, I HIGHLY recommend getting 2 brand-new bolts that hold the hpfp onto the vacuum pump. You can find them here, make sure you choose the right bolts for your production year!
INSTRUCTIONS
STEP 1: Locate hpfp/clear surrounding area
The high pressure fuel pump sits directly behind a black metal shield. I have a USP intake and had to remove it, you may need to as well.
STEP 2: Remove black shielding
Get a 10mm socket and remove the 2 bolts below. The black shield will just pull right off.
STEP 3: Disconnect fuel lines
Use pliers to take off the black hose and hold a rag as fuel will spray, then use a 17mm wrench to loosen the bolt holding down the metal fuel line next to the black hose. Fuel will spray here too, but not as violently. Use rags/tampons/your cat etc.
STEP 4: Disconnect ignition coil harness/sensors
I found that this made things much easier and faster. Use a T15 to remove the 2 bolts holding the ignition coil harness to the valve cover. Disconnect the 4 sensors that run to the ignition coil harness (2 on top, 2 connected to the hpfp underneath. I didn't take pics of this step but it should be easy enough!
STEP 5: Remove hpfp bolts
Use a size 6 hex bit to remove both bolts holding the hpfp onto the vacuum pump. Once you do so, the hpfp will be loose and everything should look like the below picture.
STEP 6: Remove hpfp
Pull the hpfp directly out. I had to slightly bend the metal fuel line upwards to fully release it. If you're lucky, you will catch the cam follower as it slips out. Unfortunately I didn't...
Here are pics of the hpfp removed. The pics aren't really good for anything, but I've used pics from other how-to's to cross reference other unrelated things I'm doing, so why not take them?
STEP 6: Install cam follower
Note the groove in the below picture, it is very important as you need to line up the notch on the new cam follower into it.
ALSO, VERY F****ING IMPORTANT!!!! Install the new cam follower JUST LIKE THE PIC BELOW! The "roller" side should seat INSIDE of the vacuum pump, and the spring on the hpfp should sit INSIDE the flat part of the cam follower. If you look at the 2nd pic below, that is how the cam follower is to be oriented. DO NOT MESS THIS UP!
STEP 7: Reverse install
Read all steps up until this point and reverse them. Use the new bolts (or reuse your old ones) and install the hpfp to the vacuum pump. Connect all sensors, and connect the fuel lines. It took my car about 10 seconds to fire up as there was no fuel in the lines. Once you start her up, check for any fuel leaks and tighten down anything if you do.
Random thoughts
Ever since I've owned this car, no one could tell me anything about cam follower replacement, or when it should be done. I've talked to lots of vendors at car events, and none could tell me anything. Most have never heard of a cam follower failure on the S4, although it does happen on the A4. I've put 45k miles on my car since I've owned it, and the cam follower I removed still looks useable. On an A4, I would have shit myself at the thought of a cam follower being in there that long. It is completely possible that the S4 cam follower requires no maintenance, but for my ease of mind it is replaced.
Also, if anyone is doing an AUTOTEC hpfp spring upgrade, you would follow the exact procedures here, but then disassemble the hpfp and install the new spring.
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Originally Posted by LittleDozer
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