Boosting Issue

[Koffee-Black]

Hey guys,

Ever since i had my car, It feels like the second turbo does not come in. It had a POD filter when I got it, and did it then. Since, I have added a FMIC and Cat back, still same issue. I installed my boost guage the other night (Thanks "justcallmefrank" works good!) and I noticed, when it works it hits .7 bar (9psi?) and when it doesnt, it reads only .4psi (5psi?)

Does anyone know what the issue may be??

Ohh its a JZA80 TT

[JustCallMeOrlando]

Good to hear it arrived fine, hope you didn't have too much of a problem getting off all that packaging

[30psi 4agte]

It could be a siezed or sticky waste gate actuator. Get a screw driver or something like that and see if you can move the waste gate flaps easily.

Could also be a leaky conection somewhere causing boost to drop off. are all you clamps tight and no holes/spltis

If you still think it is one of the turbos not working prop it may pay to check there boost individually ie T piece straight off the compressor housing and then swapping it to the other turbo and comparing readings.

[Koffee-Black]

ohh yeah, that was VERY well packed!! Thanks alot, only took about 20 mins to installt oo, as the car had a vacum line sitting under the carpet already.

[slide86]

-Are you able to remove the inlet hose to the turbo and inspect the compressor wheel? could be damaged?
-How bout a loose duct are hose clamp that could be bleeding off the boosted air before it reaches the engine....
-Got a blow off valve? thats not venting air is it?
-Checked for vacumn leaks?
-Standard boost controller? check that?
-Possible wastegate actuator or wastegate fault? jamming open.

Just a few things to look at first, im not too sure how much more there is to do with boost before it reaches the engine.
Hope you find something!

[Koffee-Black]

It could be a siezed or sticky waste gate actuator. Get a screw driver or something like that and see if you can move the waste gate flaps easily.

Could also be a leaky conection somewhere causing boost to drop off. are all you clamps tight and no holes/spltis

If you still think it is one of the turbos not working prop it may pay to check there boost individually ie T piece straight off the compressor housing and then swapping it to the other turbo and comparing readings.

I will check all teh hoses, but is there any easy way to check for a leak? I did have a quick look, and everything did seem fine. The thing is, its intermittent, it will happen maybe 50% of the time.

[Koffee-Black]

-Are you able to remove the inlet hose to the turbo and inspect the compressor wheel? could be damaged?
-How bout a loose duct are hose clamp that could be bleeding off the boosted air before it reaches the engine....
-Got a blow off valve? thats not venting air is it?
-Checked for vacumn leaks?
-Standard boost controller? check that?
-Possible wastegate actuator or wastegate fault? jamming open.

Just a few things to look at first, im not too sure how much more there is to do with boost before it reaches the engine.
Hope you find something!

Hmm, I dunnop what half this stuff is hahah. NOV is standard, could that be faulty? The vacum line to hook teh boost gauge too was not blocked, and i was hoping once the gauge is installed that would of been the problme, but nope.

Standard boost controller??? I have an aftermarket I will install soon, but whats the standard one?

Wastegate, hmm, I will ch eck this one. TT Supra only have 1 right?

[30psi 4agte]

If its intermitten then i would be looking for a sticky waste gate. no there is no easy way to find aleaking I/C hose/pipe just a thurra inspection of everthing.

[Koffee-Black]

I will check the wastegate, ive never done it before tho

[30psi 4agte]

All you got do is see if they move freely sometimes you can do it with your hand and others you need to lever it with something

[Koffee-Black]

Just tried to have a look, and its in a really difficult spot, Ill try when the car cools down, as I just got home from worky.

[YLD-16L]

For reference:

Wastegate stuck open = low boost

Wastegate stuck closed = high to very high boost

For a wastegate to stick open the spring inside the actuator would have to break/collapse and therefore it would not be an intermittent problem. Or the actuator rod would have to be snapped and again it would not be an intermittent problem.

Sorry, that probably wasn't real hepful but given you are suffereing an intermittent problem with boost being too low it does rule out the above two issues I mentioned.

[Koffee-Black]

Thanks Yld, that helps too. So i have to look eslewhere, hmmm. I was thinking of changing it from Sequentiual to TTC mode (Both come on at the same time) Supra guys say this works. as they have had the sam issue.

[30psi 4agte]

Yld
Carbon can build up around the wastegate flap and as the fap moves it can bind on the carbon build up and become stuck in the one spot! so it doesnt have to have a broken spring to happen.

Koffee Black it is worth checking!!!!!!!!!!!!!!!!! it may not be the prob but it is very easy to do and it can eliminate one possible cause for your prob.

[YLD-16L]

Carbon can build up around the wastegate flap and as the fap moves it can bind on the carbon build up and become stuck in the one spot! so it doesnt have to have a broken spring to happen.

Interesting, worth a check then I guess.

I have had turbos in my hands that have seen wayyyyy more k's than Koffees car and have had stuff all build up in the exhaust housing/wastegate basically nothing more than a light black dusty film.

I am willing to put $5 on it though that this intermittent boost problem has nothing to do with the mechanical working of the wastegate or actuator on his turbo

Let us know once it's sorted koffee