Double Throttle Control
 

I am getting what I think is a lean condition @6000RPM and 11psi boost. The car just kind of cuts out. If I let off on the throtle slightly it picks up again, i had mistakenly changed the screw setting on the dbl. throt. ctl accuator and now have know idea where to reset it. Is this the possible cause of the cut out.

3rd gen, Pettit Sequential/ down pipe.

Damn thats a good question because I messed w/ mine too. I still haven't put the car back together.

Dbl. Throttle
 

Actually I've done more reading and some guys actually remove it to reduce the restriction to the intake flow. They remove the butterfly throttle valves. The only problem is rough idle when cold. Still I'm not sure. The shop manual refers to stumblung and surging, stalling and cut out under WOT so I'm looking for someone t tell me what it actually does.

It's a protection feature
 

As I understand it, the double throttle (when operating properly) will restrict intake air flow while the engine is cold. One of the solenoids will supply vaccuum to the throttle control once a thermowax valve is warmed-up by engine coolant. I've also heard about people removing these, but you must always be [extra] mindful of hard driving with a cold engine. I'd also make sure all holes get plugged properly if I removed those butterflies.

leave them in place!
they make the car smoother to drive and generally smoother all round... I feel like a fucking idiot for removing mine.. ID glady swap manifolds with anyone!

Want2Race,

does it make the car that bad? I'd suggest wiring them open to test if you like them open all the time before you remove them.

I believe all this talk is hogwash. I've had mine out for quiet some time now with NO problems. I have intake, dp, mp, cb, and PFC. The double throttle works purely off the ECU. The ECU monitors coolant temps and activates (or deactives) the solenoid which controls the vacuum on the actuator. This entire setup is really unnessary for anyone who monitors their coolant temps or has a single turbo/non-sequential setup. The reasons for the later is that you can drive the car up to around 3000 rpm without getting much boost so this makes it easy to drive when cold, just don't get the rpms up and you really won't get the boost, meaning the turbos are really spinning that fast. This is the greater problem for driving a car too hard when cold. This reason is also the real reason for removing the AWS. (Also included is that when you replace the pre-cat with a dp, there is no pre-cat to preheat, hence the reason of the AWS in the first place!) The AWS pegs the idle @ 3k which is aweful for turbos. Pick up an Turbonetics liteture and it dicusses the various ways to destroy turbos and how to avoid doing so.

when i let of the gas it stumbles badly! It hapned when I disconnected one @ a dealer... the difference is amazing!

Just shutup and keep it! :)

Well mine doesn't stumble so what gives?

Hmm tahts odd.. So if your crusing and let off the gas it doesnt stumble?

nope . . . . you might need to look into the deacceleration system. There is an actual system that keeps the throttle from slamming shut when you take you foot off the throttle.

I've had my DTC valves off, too, and have NEVER had any type of problems. On the contrary. After removing them, I actually felt an increase in performance. The boost seemes to come on faster. I read somewhere, not sure where but I think it was the shop manual, that the DTC valves are used to prevent boost from building up too fast and to prevent a possible lean condition.

I have an ECU, so it really doesnt bother me. All I know is that removing them has actually helped, and have never had a problem with them, and no I have no stumbling.

spyfish is right. Have your decelaration control system checked out.

Well I finally decided to remove mine and I'm glad I did it. The car idles great even when she's cold and I'm glad to know that I have a higher flowing manifold and one less solinoid to deal with.

Fuel Cut?
 

Any possibility that you are hitting the fuel cut from overboost?
I think the stock cut is at 12.5, but if not the experts will surely correct me.

93 Touring Auto
AST
Column boost gauge
Y-Pipe

The stock fuel cut varies on RPM.

For example, fuel cut at 4000rpm is about 12psi while fuel cut at about 7000rpm is about 10psi. Don't quote me on this. I have the chart somewhere indicating exactly what it is. I just dont look at it since it's something I really dont need to worry about anymore.

Over Boost Cut Off
 

Many minor glitches. Well not so minor. When you need the boost you need it.

1) Cut out (Fuel?) at 6K WOT
2)9-14-9psi when first starting, engine cold, but later 8-10/9-8 when warm.
3)Sometimes 10psi boost under med. accel but an obvious power lag.

Oh Yea. can you get a vacuum reading by attaching a vacuum pump to the vacuum chamber? I mean I suppose you should it's a vacuum chamber, but I pumped for a long time without getting a reading, but maybe I didn't pump it long enough??

back to the first question
 

I have the same problem when I WOT on 3rd gear.
All boost pattern are normal until I hit 6k then a drop in speed.
But just for second then I'm back to 8 lb.
I know the boost is suppose to drop down @ 6k ( read it from scuderiaciriani )
But my boost drop is so dramatic like a fuel cut or something.
Anyone else has this problem or is it normal.

The boost drop shouldn't be as dramatic as if it feels like a fuel/boost cut. It would bleed down to maybe 9psi, but it shouldn't go any lower than that.

IS it going lower than that? You might have to start a new thread for that ;)