Ok thanks for informing me on that. So do you think overboosting causes the crank sensor code or might the crank sensor itself be going bad? Like I said, the car runs with no problems now at 5 lbs of boost if that's what limp mode runs at

 

Just wanted to give you guys an update. I finally put in a new coil pack in the #2 cylinder. I now have zero misfires and zero EPC occurrences. I'm still bypassing the n249 solenoid since it doesn't cause a CEL, so I just left it like that. I still get intermediate boost at half throttle due to the n75, but I'll probably be replacing it with the ECS race n75 later when I get some extra $. I'm glad to have the major problem fixed at least.

 

Skip doing the race N75, it doesn't work well on the DBW cars.

 

Seriously? That sucks. Why is there a difference with dbw and throttle cable b5's?

 

Yes, dbw has a MAP(boost) sensor which the ECU uses to compare actual boost vs requested boost. If the actual boost is more then 300mbar higher then requested the ECU can close the throttle to decrease boost and power.

 

Oh ok, thanks. You saved me some money then. I'm guessing it's the sensor connected to the smic? I'm guessing I'd probably get a cel if I disconnected it. If that's the case, then getting a chip seems to be the only way to get more boost out of the stock k03.

 

A diode will fix this. I used one for a while. Gives a nice spike in boost.

 

So, is the diode mod like a cheap way to be "chipped"? I mean, do you get more boost even with a stock n75 valve?

 

Yes I know seeing that I was the first A4 owner to use a Diode on the map sensor 10 years ago. lol

It should only be used with a EBC or at least a MBC. Putting a diode on the map sensor removes the over boost safety override of the ECU.

BTW spikes are not exactly a good thing. You want peak and hold. Spikes make the car feel like its falling on its face since tq/hp are dropping after the spike.


No you can not discounnect the MAP sensor, it will cause the ecu to go into a limp mode. Getting a chip is the safest way of getting more boost out of the stock K03.


Diode mod is cheaper, but you then also have to buy a boost controller like a EBC or MBC. A good EBC can cost you $200+. EBC would be the best choice when using a diode since they all tend to have a over boost safety like your ECU. If you dont use something that has a over boost safety the boost can spike to 30+psi and chances of blowing up your motor are very high.

 

Thanks for answering a lot of questions I was curious about. With the amount of $ I've spent so far on this car, I can't afford to blow up my engine over something stupid like that. For me, the safest way is the best way to go.