Mk3 not boosting ! Help....

venomstreetmachine · 08-26-2009, 10:48 PM

Hi guys, I got this sweet Mk3 with all kinds of mods.
i just built this engine with stage 2 internals.
Got a super T4 turbo with 3' V band and an external Tial wastegate.
I also have a Turbo XS T4 manifold.
I have everything hooked up but I am not getting any boost.
The turbo has no shaft play, spins freely by hand ( its brand new)
I start the car and when I rev up I should hear the turbo or see some boost but I dont. I checked all intercooler pipes and vacuum lines,,, checked OK
I reved it up to 5K RPM and let off the gas, my HKS BOV should have gone woosh ! My boost gauge shows -10 and when i gas it, it goes to 0.

Does anyone have any ideas? Perhaps anyone have Vacuum diagrams on the 7MGTE?

Also, what symptoms would occur if the knock sensor is not hooked up and the O2 sensor not plugged in?

Sp00nzZ · 09-24-2009, 06:53 AM

Yeah, i've encountered the same problem. No boost while sitting still, but boosts fine when im driving.

Dunno, sounds like it may be either a common problem or on purpose from the manufacturer.

^^ dunno, i'd like to know though.

DarkSupra2.5 · 09-24-2009, 11:32 PM

Uh guys, you should only get boost under load, as in, only when driving. If you're getting boost while just sitting there, that's kind of a problem.

kwnate · 09-25-2009, 01:06 PM

^^ Exactly, drive the car. If you still see no boost then you have a problem. And what exactly are stage 2 internals? Are we playing gt2?

ddmcse · 09-28-2009, 08:34 PM

gt2 lol . there should be a sticker with the hose diagram stuck under the hood

SupraJosh · 11-12-2009, 01:32 AM

my mk3 was boosting just fine one day and all of a suddon it just stopped boosting, i have not figured out what it is yet... i have checked the intercooler piping and vacume lines....not boosting at all.

cre · 11-12-2009, 06:55 AM

Check the wastegate... the gate or the actuator could be stuck.

EDIT: didn't see it's an external WG, still should be checked.

08-26-2009, 10:48 PM	#1
venomstreetmachine Banned Join Date: Jun 2009 Location: Abilene Tx Posts: 10	Mk3 not boosting ! Help.... Hi guys, I got this sweet Mk3 with all kinds of mods. i just built this engine with stage 2 internals. Got a super T4 turbo with 3' V band and an external Tial wastegate. I also have a Turbo XS T4 manifold. I have everything hooked up but I am not getting any boost. The turbo has no shaft play, spins freely by hand ( its brand new) I start the car and when I rev up I should hear the turbo or see some boost but I dont. I checked all intercooler pipes and vacuum lines,,, checked OK I reved it up to 5K RPM and let off the gas, my HKS BOV should have gone woosh ! My boost gauge shows -10 and when i gas it, it goes to 0. Does anyone have any ideas? Perhaps anyone have Vacuum diagrams on the 7MGTE? Also, what symptoms would occur if the knock sensor is not hooked up and the O2 sensor not plugged in?

09-24-2009, 11:32 PM	#3
DarkSupra2.5 3" Exhaust Join Date: May 2008 Location: Sacramento Posts: 60	Uh guys, you should only get boost under load, as in, only when driving. If you're getting boost while just sitting there, that's kind of a problem. __________________ 1jz-gte swap (Currently spun #3 rod bearings), Apexi high flow filter, Greddy thrust 3" downpipe, N1 3" catback with cat delete tube, 1 peice driveshaft, Bar and Plate intercooler, and 440 JDM 2jz injectors. Possible 2jz lower block swap in the works if I can't rebuild the 1j. So troublesome.

09-25-2009, 01:06 PM	#4
kwnate SP58GT Join Date: Jul 2005 Location: USA Posts: 633	^^ Exactly, drive the car. If you still see no boost then you have a problem. And what exactly are stage 2 internals? Are we playing gt2? __________________ Nate

09-28-2009, 08:34 PM	#5
ddmcse 500whp yet? Join Date: Jun 2005 Location: CT U.S.A. Posts: 966	gt2 lol . there should be a sticker with the hose diagram stuck under the hood __________________ 300+ RW HP Dyno run, jdm,mod turbo,3"exh,electfan,greddyboost Blown HeadGasket info My Supra KiXGaS

11-12-2009, 01:32 AM	#6
SupraJosh Stock Join Date: Nov 2009 Location: rockport Posts: 3	mk3 not boosting my mk3 was boosting just fine one day and all of a suddon it just stopped boosting, i have not figured out what it is yet... i have checked the intercooler piping and vacume lines....not boosting at all.

09-24-2009, 06:53 AM	#2
Sp00nzZ Stock Join Date: Sep 2009 Location: NC Posts: 1	Yeah, i've encountered the same problem. No boost while sitting still, but boosts fine when im driving. Dunno, sounds like it may be either a common problem or on purpose from the manufacturer. ^^ dunno, i'd like to know though.

11-12-2009, 06:55 AM	#7
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Check the wastegate... the gate or the actuator could be stuck. EDIT: didn't see it's an external WG, still should be checked.

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