Little Background. I have a Stage 3 Mini running a JMTC E45R K04 Turbo. It came with an upgraded diverter valve already installed on the turbo. So it literally was a direct swap when I swapped my turbo. Been on stage 3 for a while now running around 22psi. Today I was doing a real nice powerful pull peaking at 22psi then all of a sudden my boost pressure dropped to 8-9psi. I am doing more pulls and my peak boost now is 10.5psi. I've checked my hoses and they are fully connected. The system is still able to do 10.5psi so I don't think it can be an issue with the connections of the hoses. The second it happened I instantly felt like it was a diverter valve failure. No check engine lights, just a significant drop in boost pressure. What do you guys think?

Thanks!

 

Good place to start. Also could be leaking around the meth jet. Someone else had a issue like you describe and that was the problem.

 

Good idea. Will check there. What did he do to fix this problem? Used sealant of some sort?
Also anyone running an upgraded DV on an N18?

 

I believe that he replaced it. Showed up on a smoke test above a certain psi. IIRC it was wzabrouski.

 

If it's the DV, it's a quick and easy check to see how if there is any damage to it. Just don't work on it while its hot, you might burn yourself =P

 

It was I. Still trying to hunt these two very frustrating codes! I thought it was the meth jet elbow but that was not it. Had both the high and low pressure fuel pumps replaced lately, thought that was it, no dice!

 

Are you still trying to figure out the low boost issue? Sorry the picture is blurry on my phone..

 

Yep! 2C57 and 2C91

 

How long have you been encountering problems? Don't those codes mean like failed/stuck diverter? Have you removed it or replaced it? Or not yet.

 

One my second forge valve. Been back on stock for a month or so, same issue.

 

How fast does the code come back when you clear it? Do you notice decrease in performance?

 

It is generally triggered on the highway holding steady at 70-75, give it very little gas then CEL.

 

I have noticed that with the Manic tune, the car does not like to be WOT in 5th or 6th gear with the RPMs below 2500.

Not sure if it acts the same with the stock tune loaded.

 

What do you mean?

 

It kind of stumbles.

 

No cel?

 

No CEL, but I wouldn't have been surprised to get one if I kept doing it.

I rarely, maybe once a month, drive on the interstate so I don't recall if it felt the same on the stock map.

 

Found the problem. Piece of crap.

 

Easy fix though. I wonder how often it will break with the higher boost you're running?

 

Probably by design, most piston failures occur at low rpm during high load, high boost so I have been told by some smart dudes!

 

Lots of people get check engine lights with the forge unit simply because they are running the wrong unit. Is yours for the N18? I heard someone running a N14 forge unit on an N18 and couldn't figure out the check engine light. Vice versa.
Does your model match with the N18 one?

EDIT:
LOLOL. Scratch all that. Didn't read hard enough. I see that you went back to your stock one and you still have the same issue.......
When you clear the code on stock it still comes back right? ..

 

Got a yellow half engine light but no CEL. Always triggered while on the highway and would go away if I restarted the engine. Carly had codes 2C90, 2C57, 2C91. In hindsight I actually heard the problem a week or two before the car acknowledged the problem. The turbo would just keep spooling when I hit the gas making an exaggerated high pitch sucking noise forever with weak acceleration. After replacing the diverter valve with a new stock one the engine has pull again along with the turbo sounding correctly. About 25,000 miles on Manic Stage 1 and 77,000 miles total. I pretty much always run map B.