1.8T 25 - 30psi vacuum but no boost .. ??

T

The Overclocker

New member
So i finally got my hands on a boost gauge , its a srt-4 boost gauge made by AutoMeter

When nothing is connected the gauge shows -8 psi ( 8 psi vacuum )

When at idle it shows 25-30 psi vacuum

When its wide open trottle is shows 0psi boost ... ?!?!

Any idea what should i do ?

What garage to go today to fix this crap ?? Please .. This car has been a nightmare ..



Edit all the vacuum readings are actually ( in.hg )
 
scirocco16valve said:
it is normal as you said when the gauge is hooked up shows -8 and when boost it shows 0.
it is boosting 8
Click to expand...

^
As he said, if the gauge is offset you probably won't have a good reading to start with.
that would make sense if you have a stock 150hp 1.8T since they do 8.7psi of boost in stock form (11.6 for the 180)



Just make sure you didn't plug your gauge after a one-way valve
 
ok make total sense and even i wasn't feeling it but i didint know it could shift down to 8 psi off calibration ... damn ok so this is a good very good start knowing im boosting and i do feel it comparing to before i fixed my issue with my G71

but the problem remains as this car is Unitronic chipped stage 1+ since couple of days, so if i remember well its about 195hp,215lb/tq and going from around 8 psi to 18 psi ...

why am i short of 10 psi then ?
 
i would try a different gauge first, do you have a vag-com? reading the intake manifold pressure would tell you right away.
 
i dont have a boost sensor on this year, i believe the gauge was my only option to check how much boost i was gething

now im gething 8 psi as mentioned but why am i not gething my 18psi as i should ? 16 at minimum ..
 
Check your codes, maybe something is causing it to limp

What do you mean by you don't have a boost sensor? you mean the map?

ChargeAirsensorG31.gif
 
I do not have a boost sensor or map sensor on 97-99 1.8t ,

They started to have the map/boost sensor 2000+

I have a barometrix sensor next to my ecu ..

There is no check engine or codes popping up on vag com ... Im suspecting this car just being stock .. Not chipped .. But i did pay for the chip .. Does mike @ unitronic headquarters still offer client services ? Im sure he could lnow about this ...

Dv changed
N75 changed
Mass air flow changed

Everything has been changed vanclyde
 
The Overclocker said:
I do not have a boost sensor or map sensor on 97-99 1.8t ,

They started to have the map/boost sensor 2000+

I have a barometrix sensor next to my ecu ..

There is no check engine or codes popping up on vag com ... Im suspecting this car just being stock .. Not chipped .. But i did pay for the chip .. Does mike @ unitronic headquarters still offer client services ? Im sure he could lnow about this ...

Dv changed
N75 changed
Mass air flow changed

Everything has been changed vanclyde
Click to expand...

I'm sorry, i thought you had a early mk4, not a AEB A4/Passat (Should've asked what car you had.)

I don't know the AEB's all that well ECU-wise, but if you have a vag-com, look for measuring block 115 if you still see requested boost values. It may give you an idea if you have a stock chip or not.
Just make a log while making a pull.

Yes you can still contact unitronic for service(been i while since i heard about Mike though), i think they'll be able to tell you if that car has been chipped eitheir via your VIN or with vag-com (assuming the chip is signed.)
 
yeah i think im dropping by Unitronic tomorrow morning ..

im doing a boost test in a couple of hours , got what i needed from club picine !

will report back but i doubt i have a boost leak or even failled wastegate ..

the car holds its 8psi without any drops or anything, if this car would be stock it would be behaving totally normal the way its boosting

but its chipped so im troubled with this issue..

if boost leak dosent reveil something then im left with no hope ..
 
Boost leak tested

Small leak on the boot/trottle body , screwed the clamp a bit more and leak stopped

Second leak on a plastic part witch i pcv glued and funny to say it worked loll

So now i have no more leaks ( the leaks where soo small that i doubt i would have that 10 psi back...


So now im calibrating my srt-4 boost gauge thanks to samgelinas ! Thanks dude !!

Will report back in not long !
 
test drove it with the gauge default at 0 psi now ...

boosting 4psi

takes the car 12.1 sec in tiptronic to 0-100km/h
12.5 sec in automatic

when i did the boost leak test i heard bubbling liquid ... either oil or coolant is this normal ?

what would be my next step ? ?

im suspecting faulty gauge but i hardly believe this car has more then 8 psi ..

look at this guy .. he is chipped 0-100 in 7 sec ... wayyy more normal then me ..

 
Can you freely move the wastegate rod? you should be able to move it up and down by hand. Make sure it's not stuck open.
I can't really diagnose from my keyboard but if boost leaks are now dealt with i would look for a n75 leak/wastegate failure.

4psi isn't normal, and that 0-100 should be at around 9 seconds for a stock 1.8t.
 
VanClyde said:
Can you freely move the wastegate rod? you should be able to move it up and down by hand. Make sure it's not stuck open.
I can't really diagnose from my keyboard but if boost leaks are now dealt with i would look for a n75 leak/wastegate failure.

4psi isn't normal, and that 0-100 should be at around 9 seconds for a stock 1.8t.
Click to expand...

n75 isint leaking and new, the wastegate i tryed to reach and i was only able to touch it sideways but coulnt grab a hold of the shaft to see if there is play, i will try again in 20 min and this time really play with the shaft , but i saw that there is a lot of problems with the wastegate flaps braking out in the cat ?

could it be the n75 hoses arent pluged right ? but i doubt it
 
update

i think i screwed up my boost gauge or im really boosting 4psi ..

i dropped by Unitronic they where cool enough to do a drive log

the car is chipped but not enough air flow is passing tough the mass air flow

the n75 is doing its job, working at 90-99% when needing boost

im suspecting Cat clugged up

or second tough would be

the internal wastegate flap is broken off

third tough .. bad turbo < -- i hope not !!

but this car had 100k .. old lady was the owner ..

what do u guys think ?
 
maybe your wastegate is not well adjusted? (I don't know for VW /Audi but with my nsrt it was the way to adjust the boost...)

What was the problem at unitronic? Ils savaient pas c'était quoi la possibilité du problème?

Peut-être aussi simplement ton MAF qui chie dans pelle mais qui te sort pas de code...
 
Samgelinas said:
maybe your wastegate is not well adjusted? (I don't know for VW /Audi but with my nsrt it was the way to adjust the boost...)

What was the problem at unitronic? Ils savaient pas c'était quoi la possibilité du problème?

Peut-être aussi simplement ton MAF qui chie dans pelle mais qui te sort pas de code...
Click to expand...


il mon dit que tu boost pas asser

problem mecanique et non electronic

pas asser de air flow qui passe par le mass , mass est neuf

filtre a air neuf

no pour l'adjustement de boost cest le N75 qui est suposser controller sa mais dapres le data log il marche #1, je croix pas qui a un adjuste sur la wastegate

donc apres avoir fait des recherche

tres fort probable que la flap interne du wastegate est pu la

deuxieme possibiliter, cataliseur boucher

et derniere possibiliter le turbo est fini mais sa me surprend tres tres fort

je vien juste dappeller audi lauzon puis il me dise que la flap vien avec le turbo .. wtff ?

ya pas moyen de lavoir a part ? je le souderais en place sur le bras qui le fait bouger ... ?
 
the way i see it ...

i have to remove the turbo... witch i reaaaaly do not want ..

then see the surprice in witch i already know what im going to see .. a broken wastegate flap,

where can i buy just the flap !? if i would have the flap in hand , i would only remove the cat completely then tack weld the new flap in place instead of removing the turbo !
 
You must log in or register to reply here.
Back
Top