Most liked posts in thread: 2004 R53 (re)Build Thread

Drove the car for awhile today to see what I could see. Gathered more data, getting a plan together.

I drove 35 miles today, all highway at speeds between 70 and 90 mph except for maybe 5 miles on surface streets at low speeds. The car drives fine. At normal revs it seems okay. The idle is rough and sort of coughs a bit. I don’t feel like the power I felt on the first drive last weekend is there though. Hard to say for sure. Drives well but maybe not quite as responsive as it was last Sunday night.

new codes appeared during my drive:

• 0302 Misfire Cylinder 2
• 0171 Mixture control (bank 1)-system too lean
• 0234 Charge-air pressure, compressor
• 1237 Pressure sensor, intake manifold before compressor-input low

First two are obvious. No idea what to make of the misfire code persistently coming back on cylinder 2. Hopefully it is being caused by the vacuum and boost issues shown by the other codes.

The lean code is certainly true. In my 35 mile drive the car used nearly a quarter tank of fuel. That is insane to me. I felt like I could watch the fuel gauge dip.

the third code is for overboost I think. Which from what I can find is going to be the way it is if I keep the 15% pulley.

the last code is interesting to me the most. Seems to point to a pre-supercharger vacuum leak in intake. So this could be my missing throttle body bolt. But I wonder if it could also have to do with the previously-recommended bypass valve.

I’m considering several things next. First and foremost, I’ll pull the intake duct out next weekend so I can put in my new one and finally eliminate this broken throttle body bolt from the equation. I’ll clean my throttle body then as well. I’ll also put in a new intake duct to supercharger gasket (the green one). I’m now thinking about ordering the Detroit Tuned bypass valve to put in while I have that stuff out.

I’ll also try to inspect every vacuum line I can when these parts are out of the way. Mechanic already did and said they’re good but I’ll triple check.

I think I’ll check the supercharger oil levels front and back even though I just filled it last year. Although I’m now remembering I couldn’t get the back plug open and didn’t fill the back chamber. That could be a problem. Maybe I can get both open this time.

finally, I’m thinking about process of elimination. I don’t want to do this but I might replace my new pulleys with my original stock parts to see if going back to normal boost and normal crank pulley gets all of it back to normal. But I really really don’t want to do all that swapping to go though one at a time... belt off, pulley pullers, pulleys back on, belt back on... then do it all again to find the culprit. Plus, I actually want the new pulleys. Although my mechanic managed to make me nervous about using the non-dampened crank pulley. I don’t know how to feel about that decision.

thinking out loud here I guess, organizing my thoughts.

 

Ok, that's good to know... this is a classic case where "I know I saw that somewhere, last week, can't remember where..."

You all are incredibly helpful, thanks for continuing to weigh in on all this stuff.

 

You can see how it looked before in the image a posted a few days ago about the jammed BPV, and now it looks like this after my caveman attack with a drill:



I can probably pick out the rest of that hunk of slag in there and clear the hole completely. It doesn’t seem to be enough metal material in the brass fitting to do something like a helicoil but maybe that’s worth a try to get a real fastener through there.


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