7mgte Internal Wastegate Questions And (bov)

[supra153624]

ok so i have an 87 7mgte, i rebuilt the head took all the stock intake parts off and i have all aftermarket intake and blowoff valve, i think i have the vacume lines hooked up to the correct places, ok so heres a few questions.

1. why does the boost gauge "in dash" read +8 lbs when i turn the key and not start the car? after the car starts the gauge still reads +8lbs

2. when i rev up the motor to about 4500-6000 the bov does not work? the internal wastgate blows off instead so i believe, i checked this a few times its like the air from the intake is coming back out of the turbo intake instead, even when my 7mgte was fully stock it made the same blow off sound even when the stock bov was taken off

3. car over heats and builds pressure in radiator (new water pump)

4. high pitched squealing noise after engine shuts off (intake fully sealed)

 

[noah89t]

1. check the vacuum line on the stock boost pressure sensor, located on the driver fender.

2. pull off the bypass valve and try blowing through it, if you can blow through both ends, replace. did you reconnect the vacuum line from the wastegate to the turbo?
EDIT: just read again and noticed your intake and blowoff valve are aftermarket, what is your setup?

4. intake probably not fully sealed.

 

[JesseH]

ok so i have an 87 7mgte, i rebuilt the head took all the stock intake parts off and i have all aftermarket intake and blowoff valve, i think i have the vacume lines hooked up to the correct places, ok so heres a few questions.

1. why does the boost gauge "in dash" read +8 lbs when i turn the key and not start the car? after the car starts the gauge still reads +8lbs

2. when i rev up the motor to about 4500-6000 the bov does not work? the internal wastgate blows off instead so i believe, i checked this a few times its like the air from the intake is coming back out of the turbo intake instead, even when my 7mgte was fully stock it made the same blow off sound even when the stock bov was taken off

3. car over heats and builds pressure in radiator (new water pump)

4. high pitched squealing noise after engine shuts off (intake fully sealed)

what you hear is compressor surge...thats bad on the turbo... where do you have the bov mounted? its best to have it as close to the throttle body as possible for best results, also the vacuum sorce is best to have it directly off the intake manifold or as close as you can get it.

 

[supra153624]

what you hear is compressor surge...thats bad on the turbo... where do you have the bov mounted? its best to have it as close to the throttle body as possible for best results, also the vacuum sorce is best to have it directly off the intake manifold or as close as you can get it.

thanks for the tip, my bov is pretty much over the stock turbo but not directly ontop of it, i mounted the bov near the shock tower, the mass air flow meter is mounted under the frome near the turbos compressor wheel lets out into the intake, hopefully soon after i get the last part i need for it i will have it running and i will have a video for all of you to look at and to see what you think, but how do i upload a vidoe to here so you all can see it ?

 

[tlo86]

what is your vac source?

if the gauge always reads 8+ the sensor might be unplugged (its near the cruise control, says turbo pressure sensor and has a vac line attached to it... i got rid of mine as it is pretty useless)

 

[ATL88Supra]

3. car over heats and builds pressure in radiator (new water pump)

Alarms me. i would take care of this check all your coolant lines :aigo::aigo:

 

[FlikRacing]

If you have a Vac leak or that sensor is unplugged that gauge will read 8 lbs, it does not get a signal and that si what ti will do. Your radiator is building up pressure, get a new thermostat it is probably not opening at all, if it's not that bgh? get it tested and see if " compression gases " are in your system, is having problems there, when you turn off your car, I am not sure about that one.