ct26 going to 13Lbs. and then said... never mind, I rather be at 7lbs!!!!

[Aribenbarak]

7mgte gods:

I need a hand with this issue, I have 87 7mgte supra, current mods are:
Free flow 2.5 exhust
k&n filter
FMIC
Manual boost controler set at 12-13lbs.
boost gauge.
8.5mm sparkplugs cables.
all the piping is new(I mean turbo pipping)
No leaks(cheak 4 times)

I have a code 41 and 51, and find out doing test with toyota manuals, bad TPS I tried to set it up but it is the sensor (alredy order one).
But the real Q is why when I tried to go to 13lbs the boost rapidly go back to 7lbs?I remove the turbo smart tee (MBC) and happend the same with stock boost, only this time go lower than 7lbs.
I use to have a greddy profec A ( sucks) but it is no longer working (God knows why), what puzzles me more is that it is not always like this, some times work great (steady at 10lbs or 13lbs) and most of the times go al the way to 13lbs. and then return to 7 (or less ).

I apologize my English is not that good.

Can you point me in the right direction to spotthe problem?

I was thinking to change the wastegate toonethat isin DM at 11psi, guessing that wastegate is the problem.

THank you guys for your time and help, again sorry for any misspelling.

Best regards

Ari.:icon_bigg

 

[BryanDyer]

well first off fix the codes

 

[Turbo Habanero]

Could be wastegate the boost controller possibly a boost leak. I'd think about going with a 3inch exhaust and elbow and get rid of the 2.5

 

[Aribenbarak]

there is no leek,my turbo pressure meter is at 17 negative,i double check,and when ion purpose desconetc something goes to 10.
my codes does not have anything to do with boost pressure and spikes or the lack of,why a turbo will drop (ct26) at 13lbs.? it is in the parameter of the working pressure, if I go higher,yea right,but even with stock pressure there is drop and why not always?

please,any other ideas?

thank you.

 

[Turbo Habanero]

7M vac is supposed to be around 20 at idle. The spring in the boost controller could be to weak to hold the boost pressure same as wastegate

 

[Beals]

faulty wg sounds like it's only holding what the spring is meant for.

 

[Zrain25]

My vac on my autometer is 20 at idle

 

[IndigoMKII]

my idle is 22 inhg. sounds like a boost leak. how are you checking the pipes?

 

[BryanDyer]

22? really? I thought vaccum was supposed to be at -18 that's what mine is

 

[IndigoMKII]

22? really? I thought vaccum was supposed to be at -18 that's what mine is

Not to go OT but my car's engine only has about 4000 miles on a brand new long block. Last time I had a vacuum gauge to check for intake leaks, it read -22 inHG on my car and my greddy profec b spec 2 reads -9.9 at idle. I believe that's as far into vacuum as the gauge will read cause it only says -9.9 on decel too. Also, my car is only like 300 ft from sea level. IIRC, manassas regional is at 352 ft.

 

[Aribenbarak]

wow guys thank you for your responses, I will check again for leaks, best case, I have an autometer gauge at 18(best case), I'll check and get back to you on this.