# FSI No Boost



## ChunkyPeanuts (Feb 2, 2010)

So other morning woke up to drive to work, 0 PSI

brought it to my shop looked at all the boost hoses from outlet to inlet

no leaks or punctures 

so i ran codes just have it for no cat cause i have no cat

changed n75 valve lubed up DV and even changed MAP sensor

still nothing! 

so i checked cam follower which was fine

the reason i thought maybe it was MAP sensor is because when i unplug the map sensor i boost at around 7-10PSI but the moment i plug it in BOOM 0 PSI

someone maybe has some king of idea? :thumbup:

thanks guys




https://www.youtube.com/watch?v=WgnGlZPMIKM


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## Tutti57 (Jun 20, 2011)

Can you hear the turbo spooling still?


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## ChunkyPeanuts (Feb 2, 2010)

Tutti57 said:


> Can you hear the turbo spooling still?


yes sir i hear it spooling wooooooosh but nothings happening :screwy: MAYBE 1psi lol

but as i said when i unplug MAP i all of a sudden get 5-10 psi its so odd lol


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## majic (Mar 10, 2005)

Any vagcom logs?


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## ChunkyPeanuts (Feb 2, 2010)

majic said:


> Any vagcom logs?


no sir but thats the next step just figured if anyone had any ideas thats all


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## Tutti57 (Jun 20, 2011)

See what a log shows. If you can hear it spooling, the airs gotta be going somewhere. 

I'm interested to see how this one turns out.


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## majic (Mar 10, 2005)

ChunkyPeanuts said:


> no sir but thats the next step just figured if anyone had any ideas thats all


This is a long shot... But... If you had a vacuum line with a check valve in it, you'd still have vac but boost would suffer.

Now that I mention it, this leads me to believe maybe your pcv is acting up. You had it changed or have a catch can?


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## majic (Mar 10, 2005)

Vac line with a check valve that has come loose that is


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## ChunkyPeanuts (Feb 2, 2010)

majic said:


> This is a long shot... But... If you had a vacuum line with a check valve in it, you'd still have vac but boost would suffer.
> 
> Now that I mention it, this leads me to believe maybe your pcv is acting up. You had it changed or have a catch can?


i actually have the BSH block off plate but could it still make it do this?


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## majic (Mar 10, 2005)

ChunkyPeanuts said:


> i actually have the BSH block off plate but could it still make it do this?


Nah, I think that should be fine... notice any changes to your brakes (stiffer, possibly?)

Think of other things pre-throttle body that could go wrong... how about the diverter valve, if that is stuck open this could happen (I assume you have an updated one?) Double check the wiring or the plug for the diverter valve.

On the note of the wastegate, have you pressure tested it (i.e. hooked up a pump to it to see if it actually actuates?) Also, note the pressure that it cracks open.

Have you noticed any changes to the sound of the turbo? If it sounds like a dentist's drill that means it's sucked something in and destroyed the impeller/compressor blades... you'll still hear the sound of the turbo, but it's not pushing any air. 

If you disconnect your MAP and it goes to normal... hmmm... do you mean your MAF, or your MAP (I'm not trying to insult your intelligence, I'm just making sure we're talking apples to apples).


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## ChunkyPeanuts (Feb 2, 2010)

majic said:


> Nah, I think that should be fine... notice any changes to your brakes (stiffer, possibly?)
> 
> Think of other things pre-throttle body that could go wrong... how about the diverter valve, if that is stuck open this could happen (I assume you have an updated one?) Double check the wiring or the plug for the diverter valve.
> 
> ...


thanks for replying back so fast

i upgraded my brakes to the 17z brembos so yes they are stiff!

i actually unplugged my intercooler piping right before the inlet the the turbo is spooling air!

i have a forge DV & WG i lubed up the DV and the wastegate isnt stuc open or closed

no turbo sound change

and yes the MAP not MAF and it doesnt go back to normal as i usually peaked at 19psi 

when i unplug the map it give me about 5-7psi

im beginning to think maybe fuel related, i have alot of upgrades and i dont have a APR HPFP 

does that sound realistic?

lmk thanks guys


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## Tutti57 (Jun 20, 2011)

Could it be that you are only getting 5-7psi just from the waste gate and have an issue with your n75?


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## ChunkyPeanuts (Feb 2, 2010)

Tutti57 said:


> Could it be that you are only getting 5-7psi just from the waste gate and have an issue with your n75?


i changed the N75 valve on the DV

do you think the N75 on the wastegate is bad ?

also the only time i have 5-7PSI is when i unplug the MAP sensor 

when its plugged in i have 0PSI


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## majic (Mar 10, 2005)

ChunkyPeanuts said:


> i changed the N75 valve on the DV
> 
> do you think the N75 on the wastegate is bad ?
> 
> ...


This is a very tricky problem... So no logs yet? It would be interesting to see what the WG duty cycle and Dv duty cycle are. 

Hmmm... Could be fuel, but that seems less likely somehow. It sounds like your car is purposely preventing you from developing any boost. If the map is disconnected, the wastegate is probably operating on spring pressure alone (which would explain the 5-7psi because that sounds pretty close to stock cracking pressure).

Again, can you actually see the diverter valve actuating? This is tricky, because the car has to be under load... It does kind of sound like a bad n75 on the wastegate (stuck to open electronically versus mechanically). 

Tell you what, why don't you take that n75 valve from your forge and hook it up to the wastegate. Or put the old n75 that came off the forge on there... Or if you don't have two known working n75's try putting the DV n75 on the wastegate, and installing the stock electronic diverter valve.


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## ChunkyPeanuts (Feb 2, 2010)

majic said:


> This is a very tricky problem... So no logs yet? It would be interesting to see what the WG duty cycle and Dv duty cycle are.
> 
> Hmmm... Could be fuel, but that seems less likely somehow. It sounds like your car is purposely preventing you from developing any boost. If the map is disconnected, the wastegate is probably operating on spring pressure alone (which would explain the 5-7psi because that sounds pretty close to stock cracking pressure).
> 
> ...



wow , so i decided to run my CEL again p0243 wastegate solenoid ! im guessing this is the n75 valve?

also says i have misfires in 3 cylinders! will the waste gate solenoid make it do this? i changed my plugs / coils packs not even 20 ago

thanks for all the help guys eace:


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## Tutti57 (Jun 20, 2011)

I was going to say, disconnect the n75 line and see if you 5-7 lbs. 

Not sure if the missing could be related.


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## ChunkyPeanuts (Feb 2, 2010)

Tutti57 said:


> I was going to say, disconnect the n75 line and see if you 5-7 lbs.
> 
> Not sure if the missing could be related.


i disconnected both n75 the one on the wastegate & the DV 

acted exactly the same im going to over night 2 of these and see how it goes

if anyone has any pondering ideas let me know :thumbup:


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## DroppinTheSasquatch (Oct 5, 2003)

I had an issue like this, the roll pin on the wastegate was seized and wasn't allowing the wastegate to fully close / caused inconsistent boost issues.


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## majic (Mar 10, 2005)

Misfires could be related... If its not being controlled by the ecu, it's just picking whatever boost it wishes. Only theory I have for the misfires could be lean conditions on decel because the WG won't open (and is pushing more air than expected).


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## ChunkyPeanuts (Feb 2, 2010)

DroppinTheSasquatch said:


> I had an issue like this, the roll pin on the wastegate was seized and wasn't allowing the wastegate to fully close / caused inconsistent boost issues.


i just put in not even 5 months ago Forge Wastegate i checked it also it was working properly i will find out tomorrow whats going thanks for all t he help 

id be highly surprised ifi t was the WG


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## DroppinTheSasquatch (Oct 5, 2003)

ChunkyPeanuts said:


> i just put in not even 5 months ago Forge Wastegate i checked it also it was working properly i will find out tomorrow whats going thanks for all t he help
> 
> id be highly surprised ifi t was the WG


I would disconnect the wastegate arm from the flapper (mark it carefully) and just make sure - it's not the most common thing but it has happened to more than just me so I have read.

Worth the 15 min while under the car to cancel it out - to confirm, it isnt the actual flapper that is seized, it was the roll pin which connected the adjustable actuator attachment to the flapper.


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## ChunkyPeanuts (Feb 2, 2010)

DroppinTheSasquatch said:


> I would disconnect the wastegate arm from the flapper (mark it carefully) and just make sure - it's not the most common thing but it has happened to more than just me so I have read.
> 
> Worth the 15 min while under the car to cancel it out - to confirm, it isnt the actual flapper that is seized, it was the roll pin which connected the adjustable actuator attachment to the flapper.


i disconnected the actuator from the arm it moves freely i am so stuck on whats going on this is something very frustrating right before waterfest


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## Tutti57 (Jun 20, 2011)

Did you put the new parts in yet?


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## ChunkyPeanuts (Feb 2, 2010)

Tutti57 said:


> Did you put the new parts in yet?


yea i put the parts in, no go bro im so confused


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## Tutti57 (Jun 20, 2011)

Did you clear the codes and see if there is anything else in there?


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## Tutti57 (Jun 20, 2011)

Is there a way to test the map sensor?


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## ChunkyPeanuts (Feb 2, 2010)

Tutti57 said:


> Is there a way to test the map sensor?


p0243

says change n75 , map sensor or the turbocharger is bad

ive changed both so i think my turbos bad ?

but when i unplug the MAP it gives me 7 lbs!


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## Tutti57 (Jun 20, 2011)

Is it making weird sounds or blowing smoke under boost? Are you able to run logs?


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