The fusebox in an E46 3-Series is inside the glove box, and it drops when unlocking the two white tabs. Removing this #29 fuse with the key in the “off” position, and reinserting, was the quickest way to reset the EML light so I wouldn’t have to call a tow truck (pulling the #1 TPS plug would do the same thing in the engine compartment).
Thankfully, we made it to St. Louis, although not without performing a dozen or so fuse-resets, but we got it down good enough to be able to do it on the fly (in the slow lane). It wasn’t until later in the weekend, while lying in the hotel bed thinking about it, that I realized this had to be a voltage issue. After all, the problem always seemed to happen while cruising.
So, on the entire way home, I gave the car a rev blip, or dropped it down a couple of gears and accelerated to 5000 rpm. In the entire 4-hour trip home, and then some several months later, I never had a hiccup again as long as I did this. In my mind, the VAC alternator underdrive pulley would eventually have to go, although I also realized I could keep doing this and keep the extra few wheel ponies I got from my pulley install in Part 2! For the time being, I had chosen the latter and kept the pulley.
A few months later, in the spring of 2014, the battery light came on, and stayed on, but the symptoms never changed. Fast-forward to August, 2014, however, and the EML light came back after a third-to-fourth-gear rip, right as I got into fourth, and stalled the car. Well, this was new because the EML light had never happened at wide-open throttle. It was a tell-tale sign that things were getting worse. Thankfully, a quick #29 fuse pull once again allowed me to make it home. But in my mind that pulley now had to come off.
We knew the alternator itself wasn’t an issue because we’d recently installed a remanufactured factory Bosch unit from Bavarian Autosport, we just hadn’t featured it yet. At idle, however, with the large VAC alternator pulley on there, voltage would be around 12.55 volts, whereas we wanted to see at least 13.5 volts. We suspected that a possible low voltage was reaching the ECU, and triggering the EML light. To confirm, we were set on swapping the alternator the pulley back to stock.
Even with open access to the alternator, which for us required removing the top coolant hose so we could remove the plastic radiator shielding, that pulley was on too tight for our air tools. So with a good grip on some large pliers we were able to get it loosened up with one set of hands. The pulley pictured here is actually the stock one going back on. Note the size difference.
While VAC didn’t have a new belt available to switch to a stock pulley (because we were keeping the two pulleys underdriving the water pump and power steering), Gates came through with its K060605 Micro-V accessory belt, which fits perfectly. If you want a belt that will last, Gates is pretty much the name for automotive belts. They even supply belts for NHRA’s Top Fuel 10,000hp dragsters, which you can see HERE!
Unfortunately, after firing the car back up, there was no difference, except for now the EML light would only come up after wide-open throttle, and NOT while cruising! So the symptoms had flipped! To add salt to the wound, the battery light wasn't going away either. What on earth was going on here!!! The only change between pulley swaps was an engine wash while everything was out, and because some coolant had gotten spilled. Could we have faulted TPS #1 now by getting it wet? We’ll share that later.
The drive-by-wire sensors include the #1 TPS above the oil-filter housing, the one in the accelerator pedal, and the one underneath the intake manifold, on the throttle actuator. A new TPS sensor runs a little over $100, and a new pedal with sensor included runs about $140. The throttle actuator itself retails for over $600, so we were hoping it at least wasn’t that!