Turbo Gauge Not showing as much boost

[Studduck]

I have a 1990 supra turbo with a 3 in. downpipe, and the turbo gauge normally reaches +8 psi, but now it wont go any higher than +5. It still feels like the same amount of power, but I'm not positive. Any advice on whether it is just the gauge or an actual problem with my turbo?

 

[bowsercake]

Check for boost leaks. Make sure there are no cracks in the intercooler pipes.

 

[oscolivar1]

most likely a boost leak...
check BOV, all ic pipes bend'em and make sure they are not cracking unless they are hardpipes,

 

[jdub]

Check the line going from the nipple on back of the intake manifold to the boost sensor. It might be cracked.

 

[starscream5000]

^ I was thinking vacume lines also . Are your vacume lines new or old/original ones?

 

[Studduck]

What do I need to do to check for a boost leak? (other than checking the ic pipes for cracks)

 

[onefstsupra89]

boost leak

 

[trydrew]

All intake piping and couplers after the turbo should be checked.

 

[Studduck]

I checked the intercooler pipes seemed to be fine when I checked them, how do I go about checking for problems with the BOV?

 

[89turbotoy]

i would suggest getting a good boost gauge and hooking it up b/c the stock ones are very inaccurate.and you should really check the vacuum line going to the boost sensor b/c this happened to me and at least 4 people i know. it just cracks from being old.

 

[trydrew]

I checked the intercooler pipes seemed to be fine when I checked them, how do I go about checking for problems with the BOV?

If its a stock bov (bpv) then just take it off, and try to blow through it. If you can, then most likely it's shot.

If its stuck open, it will leak boost back into your accordian pipe, causing major lag. Once if highway speeds it should spool up to max boost, but maybe not as quick. The reason being that the moving air creates a simulated ram air effect, along with increased load on the engine. If you suspect it's ur bov, try blowing through it, or see if you can hit full boost on the highway (5th gear).

 

[redmkiii]

Check the hose that goes to the turbo. Thats were I had a boost leak.

 

[Studduck]

If its a stock bov (bpv) then just take it off, and try to blow through it. If you can, then most likely it's shot.

If its stuck open, it will leak boost back into your accordian pipe, causing major lag. Once if highway speeds it should spool up to max boost, but maybe not as quick. The reason being that the moving air creates a simulated ram air effect, along with increased load on the engine. If you suspect it's ur bov, try blowing through it, or see if you can hit full boost on the highway (5th gear).

So I took my car on the freeway and got pretty dang close to full boost, so I'm gonna assume it is my BOV. Would this do the trick? http://www.suprastore.com/hksssqvbov.html

 

[Big Wang Bandit]

That and a pipe flange, Go talk to Aaron at driftmotion. He sells an upper pipe replacement and BOV wth a flange for pretty cheap.

 

[trydrew]

So I took my car on the freeway and got pretty dang close to full boost, so I'm gonna assume it is my BOV. Would this do the trick? http://www.suprastore.com/hksssqvbov.html

Just to be sure, pull it off and try blowing though it.

 

[starscream5000]

^ :werd:, make sure that's where your problem is first before you go and buy a replacement for something that doesn't need replacing .

 

[Studduck]

good idea

 

[Studduck]

I checked the BOV and it seemed to be fine. I have looked at a lot of the pipes and the air filter and they seem ok, what else do I need to check?

 

[89turbotoy]

did you check the vacuum line to the boost sensor??

 

[Studduck]

It may be my turbo gauge, or the vaccum line. Where is the vaccum line for the turbo gauge? Is it on the accordian pipe or the turbo itself? Or somewhere else?