# P0234... Overboost... N75? DV? Something else?



## emmauslax31 (Apr 11, 2007)

Okay guys heres the deal

Installed the BSH Throttle Body Pipe. Since then I've been having trouble hit full boost/power. 
I am APR Stage 2+ so I should (and was prior) spiking at 21# and holding at 19# consistently. Since the throttle body pipe, running through the gears at WOT, I spike at max 15-16 and it just trails all the way off. I double checked all the clamps and such, and everything is solid and tight. the only thing I can think of is I put the water/meth nozzle (For the record, I Have NOT sprayed since installation) in the second hole, and the way BSH designed the holes, the threads taper towards the inside of the pipe so it doesn't go all the way in, I wasn't about to force it in and risk damaging the nozzle. I did not put the "goop" on the threads when I installed it, but I wouldn't think that would make a significant problem such as this. The other thing I noticed was when i do a pull in 4th, 5th, or 6th, I will spike to 21 (proper, and hold pretty long before slowly trailing off).

The other thing that just happened yesterday, for the first time, I was boosting normal (well as normal as it has been) and then all of a sudden I couldn't even make it back to zero. I was stuck in vacuum. No matter how much I down shifted and such. I turned the car off and back on and it went back to normal... No check engine light, no nothing. What is going on? and what should i be looking at? 

I should mention, I was in limp mode for a few days due to an issue with the MAP sensor on the throttle body pipe. But that is replaced and fixed and no more limp mode nor check engine light. Could that have done something??

Today driving home from work I got intermittent jerking driving, not even WOT throttle. Pulled into my parking spot and the car stalled out? No check engine light. No nothing.

Also, I am running a Forge Diverter Valve. No spacer or anything. It hasn't been serviced yet, but I plan on doing that ASAP.

What is going on? What should I be looking at? Pictures. Diagrams. Anything will help. Am I risking anything driving the car?

Another addition: Ever since installing my New South gauge a year ago, 90% i sit below 20 in/hg (maybe around 23-25)... sometimes at 20 but only like 10%...


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## emmauslax31 (Apr 11, 2007)

bump.. little bit worried...:banghead:


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## ROH ECHT (Dec 9, 2010)

It would more likely be the DV or small leak near the w/m nozzle location than the N75. A bad N75 would leave the W/G open and no boost would be built. So check the DV. Clean it, check for any scoring in the alloy of the piston and the cylinder, and lube. Hopefully it was just sticking and not fully closing. Or/and make sure the w/m nozzle is sealed well. But if the problems continue to exist you will need to log the data to make sure something isn't causing a boost cut-back.


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## emmauslax31 (Apr 11, 2007)

Well I can eliminate the DV from the equation. I picked u]p a Revision D, and put that on. Car runs the same. Several things I noticed after driving it last night.

I'm seeing the same thing going through the gears. Low boost and not holding, with spikes down low (this is with wide open throttle)

Several pulls last night in 4th/5th, had my build boost to 20lbs-ish. It would hold for a few seconds, and then you could hear the DV relieve the pressure and a limp mode would kick in and I'd be sitting firmly at 4lbs until I left off the gas and shifted either up or down and then it would build boost again... Really odd if you ask me.

I took videos of the boost gauge as well I'll try to load them up then. A few pics I took that have me wondering as well:









Car on. Dead stop. (note: since installing the gauge a year ago, it sits between roughly 20-22 at dead stop. I always just wrote this off as the gauge. Lately it's been dropping further and further


http://img.tapatalk.com/40795770-b650-38cf.jpg[/IMG
Car off. (I ALWAYS sit needle dead on 0psi with the car off... This was really odd and still doing this)


Any input will be useful. I'm just about to take it to a shop. I'm beyond frustrated. I pulled the throttle body pipe yesterday, sealed the plugs, and double checked all the hoses, the pipe is solid and fine.

I was throwing a P0238 code as well


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## tyrz (Apr 7, 2012)

bump. 

Same Problem here... going into limp mode sometimes... also thrwoing a P2008 and P3138. 
Stage 2... so sad.


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## SCIROCCO SPEED (Dec 6, 2002)

emmauslax31 said:


> Well I can eliminate the DV from the equation. I picked u]p a Revision D, and put that on. Car runs the same. Several things I noticed after driving it last night.
> 
> I'm seeing the same thing going through the gears. Low boost and not holding, with spikes down low (this is with wide open throttle)
> 
> ...


 ic:


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## Tutti57 (Jun 20, 2011)

Maybe see if the gauge is incorrect. Put a vacuum gauge on there and see what it says. 

This wouldn't explain the limp mode though.


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