I apologize if this is in the wrong place mods.

So I bought my car about a month ago, and have had problems with it spiking boost all the way up to 30 lbs. Everyones initial reaction was that it had a crazy ass tune on it.
I have since purchased a Trifecta tune which included my stock tune as well. After loading vinces tune, the car runs great, but will still spike hard if I keep it floored.
I had the car over to the dealership as I still have plenty of warranty left, and they said if its not the tune, then it is almost definately going to be the Forge BPV.

I have checked and re-checked that all of the lines and everything are on tight, so I dont think I am leaking anywhere.
Chevy says though that its going to be the valve, and that while it is on the car, they cant really do anything to help me.
I like the fact it is made of metal and seems to be a nice peice, but, I cant go WOT for more than say a half a second past 3500 rpms because it hits hard at 25 lbs or above.

Granted, its a hell of a feeling, but I really have no vested interest in blowing my turbo apart. So, any recommendations? Chevy says to take out the Forge valve and to get a stocker back in there. Of course they cant sell me one without a whole turbo with it. So do you all have any ideas? Is there something common that both them and I are missing?

 

does your engine make any type of popping/gunfire noise when it spikes that high?

 

I dont think so. The only noise I typically hear is kind of hard to explain, but I have interpreted it as my BPV desperately trying to bleed off all the extra air. Its a kind of high pitched pulsing noise.

 

so switch bpv and make them fix it
normal ts would say wg isn't opening correctly but meh let them figure that out

 

Yea i would say that something is wrong with the wastegate. swap out the stock bpv and take it to the dealer.

 

I am waiting to hear back from the guy who owned the car before me. He still has the stock valve, just have to get it from him.

Are they hard to install? I bought the car with the valve already on.

 

Ive never installed one but it looks simple. 3 bolts, take off Forge. Replace with OEM, tighten bolts. Im sure there is a how-to on it.

 

NO swapping BPV's are super easy, take your intake off, the there are 3 bolts you unscrew and it pops right off, make sure you take off that line first. it'll get in your way.

 

im not sure what the problem is...thats odd. be sure to check with vince on that it may be in the tune. but swapping the bpv back to stock is extremely simple. should take less than 10 mins

 

Thanks for the tips all.
This was doing this before Vince's tune. I was hoping his tune would fix it, but it didnt which kind of confirms to me that it is a mechanical problem.

I will find a stock BOV and get it on there. We'll see how that goes.

 

I can sell you the one I just took off, it comes with the BPV and Spring if you'd want.

 

If you have the Forge, they have to be periodically greased. Remove it and see if the plunger is sticking. If it is, you will have to grease it and massage it up and down a few times. Also, be sure that the hole in the Forge BPV is pointing in the correct direction, which is down.

 

I will try this first. What do you grease it with?

 

What did Vince say about it when you datalogged the car? He can see what the boost is doing much more accurately than you can by looking at the boost gauge while driving. Just for the hell of it I'd ask him.

 

He hasnt gotten back to me yet. Waiting for an email back.

 

Yeah Id look for what he has to say. Because if there is a genuine problem with a boost spike Im sure he'd see it.

 

My money's on the pill mod the last owner probably did.

 

If you're WOT the bpv shouldn't be bleeding off any air what so ever. Boost control is done via the waste gate (and waste gate solenoid on these cars). The bpv only opens with engine vacuum to allow access pressure to "blow off" when the throttle plate closes to avoid compressor damage.

Like everyone else is saying, just install the stock bpv and hopefully they will be able to figure out that your forge valve wasnt the issue to begin with.

 

if u have the cable try reflashing the tune, mine acted weird to first time, so i reflashed and it fixed it

 

You'll have to search for that one. I don't own one, but I remember someone greasing theirs.

 

^This

I would select "force full flash", flash the stock tune on there, and see what it does. The stock tune is a known quantity so to speak, until Vince can get back to you. If it's still boosting more than it should on the stock tune then you've got a hardware issue with the wastegate, wastegate actuator, or wastegate solenoid. The possibility of the pill mod was a good point. Another possibility is an issue with the wastegate actuator rod being tampered with or needing readjustment (though I wouldn't touch it unless Vince says something about it).

Another thinking-ouside-of-the-box possibility is that maybe it's not really boosting that much and a massive amount of MAF skew or some other MAF issue is causing the calculated boost value to be off. I highly doubt it could skew that much though. That's another thing Vince could see on the logs though when he gets back to you.

 

I think you may be thinking MAP sensor. If the TMAPS are bad this could cause a problem. Also something to look into, check the MAP sensors, the previous owner may have had 3BAR GMS1 sensors installed. Reflashing to a stock tune would ruin the sensor maps and could cause boost issues as well. All that would be needed is for you tune to be adjusted. I found a picture of the 3bar MAP sensor as a reference. Good luck.



EDIT... oh and the MAP sensors are in 2 locations. One is on the intake manifold in plain view when you open the hood. The other is on the cold side charge pipe, right after the intercooler. Take a flashlight and shine it down right in front of the engine on the charge pipes, you should see it glistening all pretty in the incandescent glow.

 

Nope, I'm thinking MAF. Our car is weird. The boost reading you see on the boost gauge/RPD does not necessarily reflect what the MAPs are seeing. The boost reading is a calculated value in our case, and is subject to skewing due to MAF skew.

You're right about the MAPs though. That's what they're there for. Both are technically TMAPs I believe, but only one is wired up with the car for temperature readings (which feeds the IAT2 info).

 

If they're the 3 bars, then they are both TMAPs. Motox is right about the TMAP. This has caused boost spikes before. If you're on stocker, let me know, and I can send you one to try out. I think they're pretty cheap, though.

 

I understand that the MAF skew can mess with the boost reading... but to have the motor boost to 30psi or show 30psi (as a false reading perhaps) is odd. That is why I'm thinking MAP issues.

OP start by cleaning all of your sensors with MAF cleaner... that would be MAF sensors and both TMAP sensors (the one in the CP and in the intake). Check the wiring to make sure everything is good to go when you have the sensors out. If you still have the problem, it could be in the MAP scaling (if the car had an aftermarket tune on it at some point that was replaced with an incompatible flash) or you have a bad MAP.

Also, I reread your posts, OP, hoping to find something I may have overlooked. When you are wide open and the car boosts to 30psi I'm assuming you hear a fairly pronounced very rapid clicking (in your second post you are saying it sounds like something is trying to bleed of pressure)... Almost like there is some lifter tick or like someone is clicking a pen really really really fast... That is you wastegate actuator and I hear the same thing. It's fairly normal on these cars Or most turbo cars with a turbo with an internal wastegate) and I have been told from multiple sources that it is nothing to be overly alarmed about.

Oh and to alleviate any confusion from my earlier post... they are both TMAPS but I interchange MAP and TMAP to describe them. That is my bad