Boost gauge install

[s4rmm]

I have connected the gauge with T-piece to FPR hose and it worked ok for a long time, but recently I noticed I'm missing couple PSIs of boost (on the gauge) - it usually holds 16-17 psi, with 19-20 spikes.
Now it shows ca 13 psi, spiking to 16.
Checked with VAG-COM, no fault codes and logged block 115 - boost is ok, still holding 16-17 as it should be.
Now, 2 questions:
1. what's the best place (hose) to install gauge's T-piece (to see boost pressure as ecu sees it)?
2. should I replace the fuel pressure regulator or what's causing it?
Thanks.

[S4TAN]

Dunno what's causing your problem with reduced boost - but I have my boost gauge 'T'd into the vac/boost line that controls the DVs (I used to have it plumbed into the FPR hose as per the install instructions - but after thinking about it I chose to relocate it to the DV line because I reasoned that it would be a good indicator of whether my DVs were holding vac/boost as they should, i.e. no torn diaghragm etc ..... )

[s4rmm]

I've read someone once suggested getting vacuum/boost from intake manifold right behind throttle body.
APR gauge install instructions also point to vacuum hose from IM, but the pic inside is not from 2.7T engine. Is it this one?

DV line seems to be another option.

[S4TAN]

I've done the N249 delete so my boost gauge is T'd into the hose running straight to the DVs from the back of the intake manifold.

[g60bv]

when you did the n249 deletion. did you find the car to be a bit lumpy and on offy boosty. ?

[S4TAN]

when you did the n249 deletion. did you find the car to be a bit lumpy and on offy boosty. ?

No - quite the opposite in fact. Much more of an "analogue" feel when you let the vac/boost pressure in the IM control the DVs with the N249 deleted, because the N249 solenoid isn't opening up the vac reservoir to the DVs (as it does even when you only slightly come off-throttle)

[Blue_Thunder]

when you did the n249 deletion. did you find the car to be a bit lumpy and on offy boosty. ?

No - quite the opposite in fact. Much more of an "analogue" feel when you let the vac/boost pressure in the IM control the DVs with the N249 deleted, because the N249 solenoid isn't opening up the vac reservoir to the DVs (as it does even when you only slightly come off-throttle)

Hmmm, wonder if it's the N249 on mine causing the jerking when lifting off the throttle?

[Ads4]

Could be Scott - mine was quite 'jerky' before I did the delete.

[spen]

You could log block 54 (I think from memory, block 54) and check your throttle plate is actually fully open. If it wasn't opening fully then the MAP sensor before the TB could read higher than the manifold?

Could your gauge be knackered?

My gauge is tapped in to the FPR pipe, but I don't like it there. I might move it to the dump valve. One day.

[s4rmm]

You could log block 54 (I think from memory, block 54) and check your throttle plate is actually fully open. If it wasn't opening fully then the MAP sensor before the TB could read higher than the manifold?

Could your gauge be knackered?

Will do some logging later this week.
Gauge has worked fine more than a year. I'll try to find another one to test.

[s4rmm]

You could log block 54 (I think from memory, block 54) and check your throttle plate is actually fully open. If it wasn't opening fully then the MAP sensor before the TB could read higher than the manifold?

Could your gauge be knackered?

Will do some logging later this week.
Gauge has worked fine more than a year. I'll try to find another one to test.

Forgot to post earlier, but taking closer look showed leaking T-piece in FPR hose. Removed it temporarily. Going to put it back into same place.