Xearo_FD3S

My primary turbo is not boosting when I step on the gas. It will some times at a little above 3k rpms then the secondary kicks in like nothing is wrong. Also, a couple times I heard a loud hissing sound coming from the bov (unusual hissing). I checked the map hoses, and my mods are as follows

HKS intake
Greddy 2 piece hard pipe kit
Efini Y pipe
Apex'i exhaust
Apes'i turbo timer

It is dumbfounding me... someone please help. My turbos as well as my whole care only has 21k miles on them/it.

Thanks in advance.

GUITARJUNKIE28

did you check all your pipes and hoses?

Xearo_FD3S

Yes I did.. as many as I can check without taking the engine out, I spent at least 20 minutes looking and couldnt find anything.

ReXtreme

i HAD something similar.

check the connections to the small one way valves. (green)

Usually a pipe has come off or is cracked which doesnt pressurize the little black airbox next to the intercooler pipes.

take off this small box for a better look and check.

dgeesaman

iTrader: (7)

It's probably something minor. Do you have a boost gauge yet? If so, try to specifically figure out what psi and at what rpm things are happening.

Go thru the http://www.autosportracetech.com/RX-...leshooting.htm site and go thru the list starting at the top.

I'm going to guess the precontrol is hanging open or the charge control valve is open (since the secondary works). But if you search thru here you'll find plenty of info.

Turbo control troubleshooting is time consuming, but the failed part is rarely expensive. It's also very interesting once you learn how it works.

Dave

WaLieN

I agree with Dave on this one. If you are getting 0PSI of boost on the primary, your pre-control actuator is most likely either off the hinge (check for that) or is just stuck open. You are probably getting boost at higher rpms due to the fact that it overcomes the open pre-control gate, thus allowing you a little boost.

dgeesaman

iTrader: (7)

It is good to check on the pressure chamber, but it cannot be the root cause of the problem. The pressure is only used to supplement the opening of the turbo control actuator, which affects secondary boost only. Primary boost comes from other components that operate on vacuum.

It is a good idea though to check the vacuum chamber (below the power steering pump) and the check valves leading to it.

Dave

Xearo_FD3S

Im kinda a newb when it comes to looking for these valves. This is the first time anything like this has happened. If someone could show me on a pic where the valves are located I would really appreciate it.

Thanks!

dgeesaman

iTrader: (7)

The green/black plastic check valves are the ones that support turbo function. The green/white valves are used in the emissions solenoids but might be switched with them (makes little difference).

Check out the vacuum diagram that shows them and gives a rough idea of their location. Generally they are tucked right behind the alternator and under the black plastic pressure chamber. This is the best place to start looking for loose / cracked / vacuum hoses.

Also, the precontrol door of the turbos can be reached best from under the car - it's the actuator about the size of a tennis ball with the longest arm. At the end of that arm it should hook over the swing arm of the precontrol door. Often the clip that keeps it in place pops loose and the arm falls loose.

Dave

Xearo_FD3S

Yes I got to that one underneath the car but I didnt know what I should do with it. I couldnt move it or anything of course I didnt try really hard cause I didnt want anything to break. But how would be the best way to figure out if that was popped off or not? And how should I go about getting back on?

dgeesaman

iTrader: (7)

It's this joint here. I have the e-clip off. This is what you'd find if things weren't working right. If this joint is connected, you're fine.

Dave

manny34711

go non-seq

Xearo_FD3S

thanks for the pic, are there things i need to take off underneath the car before i can see that joint?

dgeesaman

iTrader: (7)

Shoot, you're right there is a heat shield on top of it.

You should be able to see the front half of that actuator arm - grab it with a pliers and tug it side-side and up-down. If you can tell the end under the heat shield is moving, or anything is loose, then take off the heat shields. Otherwise, you can assume it's in place.

Another area worth inspecting for loose hoses is the charge control valve and actuator. It's on the y-pipe, under the intake hoses. (See attach.) It's also close to the BOVs and might be the cause of the sound.

To check the BOVs, you can switch them and see if it runs ok.

If these areas don't yield any loose hoses or stuff, IMO it's time to invest in a Mityvac. It will serve as a test boost gauge and be useful for checking invdividual components.

Dave

Xearo_FD3S

Yea I saw it, everything there is in place. Not sure where to look now... can I do anything else without having one of those mityvac thingys or am I screwed?

kashent

This is a couple of months late, but I thought I'd throw this on here for future people who find this thread (like me). If you want to test the pressure actuated actuators, a cheap/easy way to do it is with your tire inflator pump. Many people have them, and all you have to do is stick one of those cone adaptors on (like for inflating beach *****/air mattresses) and insert it into the hoses where pressure should be applied. Then, turn on your pump, and once you see the actuator move, pull the pump off and/or check the pressure at which it moved. Voila!

dgeesaman

iTrader: (7)

That's a good idea as long as you don't overpressurize the actuator and bursting the diaphragm. Any more than 15 or 20 psi will damage most of the actuators.