I just changed my car's pulley to a 16% and also the crank to the prw because the crank went bad. My CEL is on and I pulled up a P1242 code. Can it be that my car is just getting used to the new parts?

 

The code P1242 Secondary Upstream Manifold Air Pressure Sensor Too High in Deceleration. IMO your bypass valve is not working properly. Your By-pass valve may be sticking or is stuck also check the rubber boots on the intercooler, they may have slipped when you tighten them causing an air leak.

 

Definitely the bypass valve. That explains the late boost in third and the yo-yos haha. I went outside and played with the lever and the code went away. Is that because a worn spring? and if so where is the spring located on the bypass valve and do you think I should do the VGS mod?

 

Well at least you know why now. IMO do NOT do the mod. Many have had problems. Just get one from Detroit tuned or another vendor and you will be good to go.

 

I have this code now too. I have not yet located it. I have replaced my intercooler boots with factory boots, replaced the BPV, and the MAP sensor. My code came after replacing the supercharger with one with a 15% pulley on it. I also replaced the hose that runs from the BPV to the intake tube. all my gaskets were new. Let us know wht you find as it may help me track mine down too. This weekend Im taking my whole induction apart and inspecting. I suspect I have a leak that is preventing full vaccume to form and activate the BPV. My gas milage sucks with this code as the ECU is compensating for to much air and adding to much gas and idle rpm to compensate.

 

I fiddled with the little lever on the BPV moving it back-and-forth without removing anything. It took the CEL away... It probably loosened stuff up (i don't really know...) but i'm pretty sure i'm going to need a new one pretty soon.

 

You didn't say that you touched your intake and induction tubes. So you probably are right it was stuck. Wish mine was that easy. I need to go into service mode and pull the plastic tube off the supercharger. Well if your code is gone and it comes back you know where to look.

 

I found my problem too. My tube from the plastic plenum to the MAP sensor was broken. so the MAP got no reading and a huge vacuume leak where it was not attached any longer.

 

The plastic tube you're talking about is on the under side of the plug for the MAP sensor? I just want to check to make sure because the problems are back... =X My car is going into limp mode again. I ziptied my bypass valve until i'm able to order a new one. Does anyone know what the small hose connecting to the intake is called? Mine also has a tear in the hose. Duct tape will hopefully hold it for now...

so many problems piling up!!

 

Not sure if you've discovered realoem.com yet. If you're not farmiliar with it, click the link here to check it out. http://www.realoem.com/bmw/partgrp.d...id=48021&hg=13

The diagrams and what not have been very helpful to me.

From the front page, just choose your year, make, model, etc, then Browse Parts. You can do it by part name, or click to Drill Down Images and get thumbs of diagrams to look through instead.

 

okay so I got the detroit tuned bypass valve installed and the car started barfing up even more codes.

P0420
P1125
P0638
P0506
P1498
P1242

I checked under the map sensor and the tube is also broken... so I just ordered another tube for it... I'm going to take everything apart and reinstall it and hopefully that takes care of the codes... sldakjfalks;dfjlaksdf -_______-"