Possible TTC problems, not sure.

Hi Guys,

So, I tucked my Supra away for the winter and have only just had the money to get her back out.

I notice that the maximum boots I am hitting is 0.74bar when I was usually hitting up to 1.1 or 1.2 (1.2 restrictor ring in) I have checked IC pipes and hoses, hoses to turbos while under boost and I cant see anything out of place or split.

The other thing that I notice is that usually when I start her up, you have to give it a quick rev to remind the (actuators?) that they are running in TTC mode, and you can hear the definitive tone drop in the exhaust. Well, this happens as per usual but as soon as I let off the throttle, everything turns back to sequential mode again and I have to rev it to bring it back down.

I have checked the wires and nothing seems out of place either... totally confused:blink:

Any ideas chaps?

Is it not on a standalone/piggyback ECU, from what I've heard, TTC will never work properly or reliably unless the car is mapped for it.

I thought you had to swap vaccum hoses around to change from the o/e sequential set up to the parallel set up so how can it swap from one to the other ? dont understand that but never tried it as i'd be concerned about the fueling etc

True, well maybe I just need to turn it back to sequential again (take all the wiring out) and see if it boosts correctly then...? It just seems odd that I cant produce more than 0.7

I thought you had to swap vaccum hoses around to change from the o/e sequential set up to the parallel set up so how can it swap from one to the other ? dont understand that but never tried it as i'd be concerned about the fueling etc

You can electronically TTC a supra, theres a few guides around on here or the US forums somewhere...

I notice that the maximum boots I am hitting is 0.74bar when I was usually hitting up to 1.1 or 1.2 (1.2 restrictor ring in) I have checked IC pipes and hoses, hoses to turbos while under boost and I cant see anything out of place or split.

How did you check the pipes and hoses under boost? You have to "load" the engine to get in the higher boost range! Revving the engine does not produce enough boost to find a leaking hose/tube.

There could be a small crack in a hose or vacume tube. To be sure: remove and inspect all piping and tubing.

I have removed all VSV's/actuators/valves so no going back to sequential for me. But then again... the car hits 1.3bar without any problems... always...

Good luck, boostproblems are always a PITA!

Dennis

Cheers for that Dennis... I might do the TTC properly, ie, not electronically, I never liked the sequential system much anyway

Is it not on a standalone/piggyback ECU, from what I've heard, TTC will never work properly or reliably unless the car is mapped for it.

Agree I wouldn't run TTC without an ECU mapped to suit, cams will also help get the best out of the mid/upper end power delivery.

Thought id update on this... somehow the IACV VSV hose had come off... its a tiny little begger I tell you. Anyway, all sorted!