3sGTE Boost controllers.

[worldwalker]

+rep Justen! Thanks for the help, I can see where the issues are now. I'll fix it as soon as I get home! Fingers crossed...

Nick

[JustenGT8]

good luck mate.

If all all fails a 30cent zener diode will work as a FCD and fuel goes full rich once past boost cut so up to 16psi it won't go bang.....far from optimum though, better to find issue and fix.

[sw20r]

the stock turbos can overboost quite abit.

mines set to run 15psi, but lately due to cold temps about 6-7degrees on the open highway i spiked to 26psi on 3 occasions. Im using a Profec2 EBC but turned it off once it happened.

My setup is - CT26 from st205 GRP A. 3" Dump then straight to mufflers. Having a free flowing exhaust exhaust will contribute to bad boost controllering

[JustenGT8]

the stock turbos can overboost quite abit.

mines set to run 15psi, but lately due to cold temps about 6-7degrees on the open highway i spiked to 26psi on 3 occasions. Im using a Profec2 EBC but turned it off once it happened.

My setup is - CT26 from st205 GRP A. 3" Dump then straight to mufflers. Having a free flowing exhaust exhaust will contribute to bad boost controllering

That's got nothing to do with the turbo, the stock twin port WG will flow enough to control any boost the stock comp wheel can produce. Running just a DP with a well designed WG merge i still had good boost control......volume control was a little outta control though

[wiso]

You want to disconnect the VSV line as that little bugger will cause you no end of trouble. You'll see 2 ports going into the top of the actuator. the line that snakes away around behind the engine you want to pull and block off that actuator port. leave the other short one which should be straight from the compressor housing to the actuator. That line is now your boost control line. On a stock car this should give you 6psi and with exhaust mods maybe 10psi. Any more boost than this and you have some type of wastegate issue (jeez i hope there's some rep in this )

shouldn't the VSV be keeping the boost at stock level regardless? since that takes the excess boost away from the wastegate actuator it shoud remain at the standard 8psi or whatever no mater what. if this was disconnected then you should be seeing more boost with free flowing exhaust ect. but if still attached and in working order the boost shouldn't be creeping

[JustenGT8]

Nup, you have it backwards Joel. The VSV is toyota's overcomplicated version of a bleed. It's just a solenoide valve that bleeds off boost pressure signal to the WG actuator to give you 8psi...stock spring pressure will give you 6psi only (with stock exhaust etc).

The VSV will eventually play up and give you annoyingly inconsistent boost. Just ditch it, it's only there to spoil your fun and reduce boost anyways

[wiso]

ohh ok, i dunno, mine only stayed at stock boost for not even a month before a boost controller went on and disconnected the vsv

[worldwalker]

Ok, I've found it, when I plug it do I plug both ends of hose (actuator side and VSV side?)

Thanks again

Nick

[wiso]

yeah you have to seal the actuator end, its a good idea to seal the vsv (a vac cap will do that though) side as dirt and shit can get down the pipe

[JustenGT8]

Absolutely must seal the actuator end. VSV pipe isn't critical but may as well block in case you ever use that vac line for something else.

[worldwalker]

hahaha I take it the VSV is possibly the most pointless thing toyota has come up with next to having a control box for each and every electronic item on the car, I wouldn't be suprised to see "dome light control unit" on a new corolla.

[worldwalker]

Ok, I did as you guys said and it still cuts out. This time I had the boost gauge hooked up.

During the day I was getting 8ish low in the revs then picked up to 11-12 at WOT from about 4 - 4.5K RPM. I figured that it was solved but I'd test it tonight to be sure.

Again 8ish down low then 12 at WOT from 4K hit 5K and came up to 14 then cut. Then the car was undrivable until I restarted the car.

Any idea? Maybe I should start a new thread...

edit: The car is almost undriveable as a daily with the exhaust the way it is so I'll be switching to a twin 2inch from cat back soon. Plus its too fucking loud even for a toy.

[JustenGT8]

You have a wastegate problem. It's not opening fully for some reason....symptoms match. ie it can control boost at lower rpm but as exhaust flow picks up the WG can't pass enough exhaust gas so your compressor speeds up and you over boost. Nothing to do with the exhaust, back to fouling or sticking WG flap or dodgy actuator not fully opening.

[worldwalker]

Is the fuel cut ment to kill the engine like that? As in is no longer driveable until its restarted? I used to hit fuel cut in my old car, (peak revs) but it would only stop over rev. It wouldn't render the car undriveable...

Also how do I go about fixing the problem now?

[JustenGT8]

Yup (185 right?). Once you hit the fuel a few times the ECU thinks ah ha, a problem and goes into limp mode. Limp mode gives you a 3 psi limit so yeah, makes the car pretty well undriveable. Pull the engine fuse for 30 sec to reset the ECU...or disconnect the battery for a more thorough reset (lose your clock and stereo settings etc though).