doing vac hose job:Double throttle control solenoid broken?
 

Ok, while doing my vac hose job, i did infact notice that the frontmost solenoid, as per vac hose diagram called the " double throttle control" solenoid does have a broken nipple on it. This was not something i had broken.

FYI: this is the solenoid marked by a green sticker on it. It has a vac hose that runs to the UIM.

Anyways, prior to doing my vac hose job i was experiencing some boost issues. They are detailed below:

1)put car in 2nd gear, bring it onto the secondary turbo (doing approx 45-50mph) and then drop the hammer. You could feel the car "surge" and almost "buck". Car feels like it's down about 20hp. Run the car to redline in 2nd, put it in 3rd and when you get back on the gas and you are on the secondary turbo, **the problem goes away**. For 3rd 4th and 5th the problem is not apparent
2)put car in 3rd gear, tooling around town say about 30-35mph, car is taching below 3500 rpm. Roll into the gas, when car reaches anywhere from 3000-3500rpm as boost is building and acceleration is picking up, it suddenly hits what feels like a fuel cut(car stops accelerating, it happens very suddenly). It will continue to run this way until you get onto the secondary turbo.

I spoke with Brian from Rotorsports and he feels it may be a fuel cut. **The car is bone stock and has NO mods whatsoever** which is why this is so confusing. Can anyone offer any insight to this problem?

And secondly, does anyone have a used Double Throttle Control solenoid? I believe the numbers on the solenoid read: 2B3

I am actively seeking a used solenoid if anyone has one. TIA everyone! :)

Darril

The double throttle acts to restrict acceleration while the car is cold. If the nipple was broken off, you will have a vacuum leak, that could cause the problems you are having.

If you want to eliminate the vacuum leak, without replacing the solenoid, you can simply cap the lines where they enter the intake manifold. This will disable the double throttle system. Your car will probably run better, as the vacuum leak will be gone. If you do this, you must be carefull not to accelerate hard until the car is warmed up.

Adam, thank you for your response. What mods do i have to do to the Double Throttle solenoid itself if i cap off the nipple on the manifold? If i can avoid replacing the solenoid i will do that.

Darril

The soleniod vacuum lines enter the manifold on the front and back. Simply remove the vacuum lines from the manifold, and cap the nipples. No more vacuum leak, and the solenoid is disconnected. That's it!!

Please make a post if you do this. Let us know if it fixed your problem. I will bill you later :)

The double throttle is normaly open and pulled closed by vacuum - so to disable it all you have to do is pull off vacuum lines and cap the source on the uim.

Yes, pull the vacuum line attached to the double throttle control actuator (located behind the extension manifold...everyone calls this the upper intake manifold), and cap the source. You essentially disable the DTC, and leave the DTC plates open within the throttle body. Be careful accelerating when your motor is cold...wait til the motor is nice and warm before accelerating to WOT. Actually since you've disabled the DTC, system, you might as well remove the DTC butterfly valves for better air flow down the intake manifold :)

Thanks for all the replies guys.

So do i remove the actual Double Throttle control solenoid altogether? Or do i simply leave it unplugged from the electrical plugin? I noticed there is a breather on the solenoid itself, and another vacuum line that goes up to the UIM totalling......2 vac lines that go to the UIM? I'm a newb at this vac hose stuff :)

Darril

I am also curious if that breather line has to be removed. I disabled my double throttle soleniod and capped the intake manifold lines, but I still have that breather there.

In case you need another one.... I've got one in the garage.

You have another double throttle solenoid? The '2B3' solenoid with the green sticker on it? Just out of curiosity, how much are you asking for it? TIA :)

Darril

all solenoids function the same...sticker helps plug it into the right connector. May look different because of how it points on the 'seat' and where the breather is.

But if you are to remove it...pull the whole solenoid and cap the nipple on the UIM and pull the actuator and butterflies and blockoff that hole, simple mod adds like 50 hp :rolleyes:.

Very well.

How would i go about removing the butterfiles for the double throttle mechanism? Would i be hurting anything by NOT removing them?

How about 18 shipped?

Wonder1and, that sounds very reasonable, provided it is in good working order. However, i'm going to contact Brian@Rotorsports tomorrow to see if i can actually eliminate the Double Control Solenoid altogether and absolutely positively not sacrifice any reliability or drivability to the car if i remove the solenoid.

I always give the car ample warm up time, so that is a non-issue. I'm wondering if there is any other consequences to removing this solenoid :) If Brian says i need the solenoid, or if any other members here say i need it, you will be hearing from me :)

Darril

By the way, i'd like to thank everyone for helping me resolve this little matter! :D

Thank god us rotorites are such wholesome, down to earth people :)

Darril

ok let me know!