Very low boost

[markssupra]

Hi all,

Recently started having a few problems with boost. Car is BPU with Profec B spec2 BC, RR, tc.

 

First started out as if the EGCV pipe had come off and was only boosting to about 0.8 bar, checked this and pipe was still on.

Fault appears intermittant as after trying again it was boosting with turbo 2 coming in normally upto 1.2 bar. After another try the 2nd turbo was not coming until over 5000 rpm.

 

Now I only have a max reading of 0.08 bar boost on the Profec BC, although I can still hear the turbo's spinning but feels like I am getting some boost from No. 1.

 

Any ideas, as I have have checked and replaced vacuum hoses that I can get too, checked IACV vsv as per instructions in Toyota manual and the only difference I found was that resistance reading should have been between 33.5 and 44.5 Ohm's, it measured 63.2 Ohm's.

 

I have applied pressure to the control valve and it is opening, also applied pressure to the EGCV valve which is opening. I still need to check the EGCV vsv and EGBV but not sure what else to look for. I have checked the intercooler hoses but I only replaced this a few years ago with a frontmount and new pipework.

 

I cannot understand how it appears to have had all the problems listed in Ian C's guide and now only boosting to 0.08 bar.

 

Grateful for any advice.

[markssupra]

Can anyone tell me how to do the TTC mod to check the turbos. I want to do more checks before I give up and take it Paul Whiffin.

 

Thanks

[Scott]

You need a length of vac hose. Around 18" should do it. There is a guide on here showing how it's done. If you can't find it give me a shout and I'll go through it with you.

[mellonman]

its on here somewhere if you do a serch, that would let you know if its a vac pipe and vsv by it holding the egbv open with the stored pressure in the sequencial system

[markssupra]

Thanks for the help. Problem now sorted, found a vac pipe off the pressure tank vsv. Replaced both and now boosting to 1.15 bar again