Way too high boost but not actually boosting

[Razor_nl]

Hey guys,

I have a JDM 6bolt in my 2G with a big16g on it. It all worked fine, I boosted for a while at default ~0.7bar and now for a while at ~0.9bar (12psi or so i think)
Everything was just working fine for quite a while until last night. I boosted in 2nd gear and all of a sudden revs went up way "too fast". Im still not sure if it was wheelspin (fwd on wet road boosting) or something else. It felt a little different than wheelspin.
Anyway I noticed my (aftermarket) boostmeter go up way more. So in a reflex I released gas pedal. The car just ran perfectly fine and I drove home without any problems. This morning I could start the car normal and drove to work without problems again.
I did some testing and noticed the following:
My boost meter goes up to like 1.6bar and it seems to have no end (the needle just flies up). Of course I did not test the end of the boost because Im afraid to damage stuff. But my Greddy boostcontroller doesn't register any boost. Neither the warning or limiter function does anything aswell, peak boost shows 0.. nothing. I tried to turn the controller off to see if it was malfunctioning but still boost went crazy high. I also tried to adjust one of the 2 modes with different (lower) numbers for boost etc but yet again no difference at all.
The weird thing is tho.. i don't feel boost! As in, the car does go faster when hitting the pedal but in no way as fast as before when boosting. Hard to judge if it boosts but it feels like before my engine swap (4G63 non-turbo before) Also my SSQV makes the "flutter" sound when releasing gas pedal as if there was no boost (it used to make a whoosh at very low boost allready and flutter under vacuum only)
So we have a boostmeter showing a crazy high boost, but the boost is not there (doesn't feel boost and no ssqv sound) and the controller sees no boost at all... And the car still drives normal and smooth, idle is fine (no idle surge due to a leak or so)... Also no other weird things like liquids under the car or smoke out of the exhaust or any other place.

What could be wrong? What should I check? What could be damaged? Please help me out!

 

[r1991_4g63t]

you could actually be putting out too much boost causing knock which retard timing making it feel like there is no power,

 

[Razor_nl]

But could that be caused all of a sudden?
I mean I drove fine for a few months with this boost pressure without problems ever.

My guess by logical thinking was that my wastegate is gone and therefor it boosts so high (and maybe because of that the controller doesn't register any boost since its connected to the wastegate if im right)
And you might be right that I'm having knock because of too much boost and therefor feeling no boost... Only thing that does not fit in this story is the ssqv sounding like there is no boost at all.

Maybe its complete stupid, i'm not a big tech myself.

 

[winterftbl]

Check your vacuum lines for leakage, also check your wastegate lines and see if those are leaking as well. What is your vacuum at idle?

 

[r1991_4g63t]

when my wastegate line melted i had similar problems, high boost no power and my stock BOV got alot quieter. and it all happen rather quick. within a couple miles of running perfect it ran like crap

 

[Razor_nl]

Check your vacuum lines for leakage, also check your wastegate lines and see if those are leaking as well. What is your vacuum at idle?

I did a quick look at the vac lines and they all seemed fine, not damaged or disconnected.

My vac at idle is the same as always and idle is fine as well, just stable at ~900rpm. The boost meter goes from -1 to +2 (x100 kpa, bar) and it usually sits around -0.6 to -0.8. Cruising while maintaining the same speed goes at about -0.4 to -0.5 , again exactly the same as before so I doubt if it will be in the vac lines.

 

[ShadyGST]

Is your clutch slipping?

 

[awdclipse]

I boosted in 2nd gear and all of a sudden revs went up way "too fast". Im still not sure if it was wheelspin (fwd on wet road boosting) or something else.

First thing to come to mind also is a slipping clutch. Cruise in 5th gear at a low speed and hit full boost see if it holds steady, if it goes "unlimited" still it seems you must have a wastegate/vacuum issue

 

[Razor_nl]

At first I was thinking at a slipping clutch as well. I know about the 5th gear test so I did that allready and it doesn't slip. Also when normal driving my clutch is absolutely not slipping. (it's not that old anyway and I don't race/drag so it should be still fine) I think it might've been wheelspin after all. It was quite wet and usually when it's wet I don't boost at all, just on dry. And wheelspin on dry road feels a bit more rough and bumpy and all, and now it almost felt "smooth" Not sure, just a guess.
(I hope you get what I'm trying to explain)

I've called with my mechanic guy who did my swap and he also thinks at the vac lines or something wastegate related. But most likely not vacuum since idle and daily driving still goes just as before. And that's what I also think. So then the only option left should be something wastegate related.

Can anybody tell me what I should check and maybe even where I can find it and how it looks? (I do know what and where the wastegate is by the way, just not sure what to check and how to see if something is wrong) If anybody needs pics of things just ask by the way and I'll make them.

 

[Razor_nl]

PROBLEM SOLVED

I did a better double-check at all the lines and hoses etc and I noticed something at my ssqv v1.
The long thin plug for the vacuum hose was lose! But because it's a very short vacuum hose till a T-piece it didn't hang out all the way down, so when you look at it fast it looks like it's still fine.

So I've put it back into the ssqv and it's much better now. Boost holds again alltho it creeps a bit. I assume that's because some air is escaping via this plug so I'll put some thick glue stuff (don't know the right english word sorry) around it to make it seal the air again.

Thanks for help guys!