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whats your MAF input.

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Your PCV isn't working properly. Mine has a good PCV on it. The cap is initially tight when I attempt to loosen it. When I remove the cap...idle drops and struggles. When I place my hand over the filler opening...the idle recovers and I feel vacuum.

Ooops!
 
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Skono

New member
Location
Australia
Car(s)
Mk5 GTI
I have a PCV delete, with the intake ports removed only leaving that crankcase one. But yeah there was no drop in idle at all there was a slight hiccup but nothing notable
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
My mistake....I was thinking I was replying elsewhere perhaps. Been dealing with a lot of PCV issues today.

So yeah, there could be a bit of blow-by at idle...but strange that it isn't sucking through the turbo inlet. Makes me think you have a valved rear breather tube. Do you know?
 

Skono

New member
Location
Australia
Car(s)
Mk5 GTI
My mistake....was thinking I was replying elsewhere perhaps. Been dealing with a lot of PCV issues today.

So yeah, there could be a bit of blow-by at idle...but strange that it isn't sucking through the turbo inlet. Makes me think you have a valved rear breather tube. Do you know?
That line there?
There is a fair bit of air releasing from the oil cap filler hole. Not sure if this is normal but no vacuum sucking in what so ever
 

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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Yeah, that's it. But I wouldn't suggest disconnecting it just for having a look. Because, valved or not, it may not be a lone factor in the low mass air you see. It would only explain the symptoms noticed when removing the cap.

With that, if there is a lot of pressure/blow-by coming out of the crankcase due to age and wear...I'm thinking this could maybe reduce the mass air volume you are seeing. Increase in blow-by air will go into the turbo inlet and possibly reduce the air flowing over the MAF. Just a theory. Hmmm...this one is going to be a thinker. You still running an old MAF? I would only use a genuine VW MAF if it's replaced. But try the leak testing.
 
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BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
On ROH's point of the MAF age as well as the intake itself, if the housing for the MAF is not shaped correctly it can throw off the scaling, even with a new MAF sensor. Before you go replacing the intake though you may want to consider replacing the MAF. Cleaning my old one helped a little, but a new OEM MAF provided much greater improvements.

Can you share any specifics about your intake aside from the fact it's an inexpensive Chinese part? Upload a picture?
 

Skono

New member
Location
Australia
Car(s)
Mk5 GTI
On ROH's point of the MAF age as well as the intake itself, if the housing for the MAF is not shaped correctly it can throw off the scaling, even with a new MAF sensor. Before you go replacing the intake though you may want to consider replacing the MAF. Cleaning my old one helped a little, but a new OEM MAF provided much greater improvements.

Can you share any specifics about your intake aside from the fact it's an inexpensive Chinese part? Upload a picture?
It has a OEM MAF on it at the moment. I’ll upload a picture of the intake, it’s similar to the CTS intake. Not sure on the depth the actual sensor sits inside the pipe which I’m thinking cold be an issue. OEM MAF is $380 would be a kick if neither that or the intake is the issue.
 

Pudding

Passed Driver's Ed
Location
UK
Edition 30 (K04)
Revo Stage 1 - B7, T5, F8 on 99 octane pump gas (US equiv' = 94)
245g/s @ 6300rpm in 4th gear @ sea level.
0.3% LTFT over 6 months.
Stock Intake with OEM paper filter
Stock exhaust
 

Skono

New member
Location
Australia
Car(s)
Mk5 GTI
Recently put my stock air box back on and have done a few logs currently seeing MAF readings at 205.3 at WOT on 3rd gear pull. Glad that has corrected the issue of the low readings with the cheap intake. Reading seemed fairy high for the stock air box but wont complain with that. Looking at moving onto the IE intake as from a bit of research seems to be the play.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
So the PCV delete would make it so you only feel a bit of pressure at idle with the oil cap removed because of blowby in combination with the intake manifold no longer applying vacuum to the crankcase.

Obviously the scaling was off for the MAF. Your fuel trims may decrease, your mpg should also go up, and it now shows 206 g/s = 255 HP. Probably would show more mass air with a new MAF and the oem airbox.
 

Skono

New member
Location
Australia
Car(s)
Mk5 GTI
So the PCV delete would make it so you only feel a bit of pressure at idle with the oil cap removed because of blowby in combination with the intake manifold no longer applying vacuum to the crankcase.

Obviously the scaling was off for the MAF. Your fuel trims may decrease, your mpg should also go up, and it now shows 206 g/s = 255 HP. Probably would show more mass air with a new MAF and the oem airbox.
Car is booked in next week for the upgraded HPFP internals and a new map to suit. Was hoping to have the integrated engineering intake by than but suppliers are out of stock.
looking at what APR state for stage 2 seems to be around 15hp off target this is probably due to health of the engine.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Could be health...also, the MAF sensors do fade. I've had two previously drop to below 250 g/s from over 270 g/s. I replace them and mass air goes back to over 275 to 280 g/s. I know some with K04 hybrid and big turbo still using the oem airbox with a performance drop-in filter....just so the MAF reports more air and does so without restriction.
 
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