puma

iTrader: (2)

Hi, i just retrieve my second turbo but now it seems to take a lot of time to come on. The transition drop to 5 lb.

Is it normal that i don't get second turbo boost in first gear, it just drops to 0 at around 5000 in first, they other are fine except for the transition

If anyone could tell me where i should strat looking for, it would be nice

thanks a lot

puma

f2racer

iTrader: (1)

If you're making a solid 10 shortly after 4.5k rpm, it's likey that you'll need to "adjust" the pill in precontrol actuator vacuum line by using a needle valve instead. This line controls when exhaust is "shared" with the secondary turbo under 4.5k rpm. If there's not enough pressure against this actuator, you'll get more of a dip. Too much pressure and you may see a spike at transition.

Turbo problems are a b*tch. Hope you sort your car out.

EugeneChoe

puma what did you do to retrive your 2nd turbo

potatobbq

Hey f2racer, you usually seem pretty knowledgable... What do you think could be cause of the secondary not getting full boost? Mine is doing something like 10-8-8 and I get around 17 mm of vacuum at idle... Also my idle is a bit high at around 1000 rpm. Any ideas?

puma

iTrader: (2)

well my problem was a check valve.

What is that damn pill, everyone is talking about it but i don't know what it is.

puma

KZ1

the adjustment of pills is not yout problem. They are stock restrictors in WG and TPC tubes between the primary tubro and respective actuators. You do not need to install valves. That is only if you want to alter stock settings, ie boost spike or increased boost. if you are not getting 10 8 10 there is somethign wrong. You can if you want make sure the pills are there. obviously your WG pill is there you TPC pill may be gone, so check that.

Is boost in other gears on secondary slow to build, like does it get 10 on primary, drop to 5 and slowly build to redline, and oviously quicker in highers gears? if so definately your Turbo control actuator. In which case the pressure or vacum side of that actuator is off, ie leaking, poped off bad selenoid, etc. At 4500 rpm pressure is sent to one side of the actuator and vacum to the other to ensure a quick switch and transition of exhaust routing. However if one side doesn't work you will get a lazy actuator casuing no high boost in 1st gear maybe second, and slow to build in others.

However, if it drops to 5 but then build right away it probably is your turbo precontrol actuator. It sppols up the secondary before it comes online, so if it is not fucntioning you get a huge drop at transition, but immediatly starts to build. Test its selenoid, and plumbing for proper operation. this is were the pill comes into play and why it was mentioned earlier. everythign that was said is true, but you do not need aftermarket needle valves. the build delays the build up of boost in the actuator. the greater the pressure in the TPC actuator, the more it robs from priumary to pre-spool the secondary. the pressure is vented by its selenoid which is the upright selenoid to the left of the WG selenoid. Make sure selenoid works by slapping 12 volts to it. then take off the line from the TPC actuator to the primary turbo, and stick some pressure on it to make sure it moves. if some of these things do not happen you know where you problem is.

I would do the TPC first becaue it is easier to get to. All testing of these can be done with out removing the intake manifold. If you remove the pressure chamber you will see the pressure deleivery hose to the TCA, "T" it with you boost gauge and observe it jumps immedialty to >7psi and builds to boost levels. You can get an exact location of this from vacuum diagram. You want to tap into the hose coming from the top of the TC selenoid. (the one in the rack, not the vacuum one) this will test pressure to the TCA. If I remmebr right the vacuum selneoid for TCA is out of reach unless dismantling everything, so the easiest is to "T" into where the lines collect infront of the TPC and WG selenoids, use your vacuum diagram to locate the rail that carries vaccum to the TCA. tap it, and make sure it works. by observing vauum at transition.


Sorry for the rambling, just thought it may be of help to other people as well.

altrdego

This sounds just like what I've been experiencing lately.

The boost drops low probably 10-5-15. It builds slow. I can recall that the car used to have a real kick in the pants at 4500 rpm. It would easily spin the tires when the 2nd turbo came on line in 1st and 2nd gear. There is kind of a second turbo rush, but it is no where near as profound as before.

I think the hose job is in order...

Any one got a lead on a good kit?

What color hose for a VR engine bay?
(I'm thinking blue with yellow tie wraps.)

puma

iTrader: (2)

wow, thanks a lot

i ain't sure i understood everything you wrote but i am going to read it again and again.

I was thinking also that it could be the precontrol but i didn't know where to start with to see what to check for that precontrol. If you tell me that this pattern is looking like a precontrol problem, than i will start with that. I believe that my pressure is building pretty quick on my secondary turbo.

Also, i just retrieve my secondary and that was a turbo control problem because the check valve on the vaccum line was stuck. What it gave me is that i had no second turbo in 1-2-3 gear but i had some in 4 and 5.

I am going to check the precontrol, thanks a lot.

By the way, i am going to keep that post in my archive.

puma

f2racer

iTrader: (1)

If your boost is (quick to 10psi at or around 3k rpm, drop to 5psi at 4.5k rpm, and builds REALLY quickly back to 10psi probably before 5.5k rpm. It is either a precontrol or precontrol "control" problem. My suggestion would likely fix it (putting a needle valve on the vacuum hose that runs to the precontrol actuator which stock comes with a pill and letting the air be less restrictive in that hose), but may mask some other problems that you are having. The high idle says leak somewhere. Have you tried adjusting your idle? Does it stay at 1k nomatter how far you turn it down? If it does, you have a leak. I'd try with the hoses that are around the precontrol actuator and the control system (solenoids) that also controls it. It's likely to be a cracked, loose, or leaking vacuum hose.

KZ1

F2 racer is right you could try adn restirct that hose and see i f your pattern returns, that may give you indication as to wether selenoid is bad.

I am struggling with a different but similar problem of my own. I too have low transition at maybe 5 or 6 psi, however my pre-control system works 100%, I check actuator rod movement, leaks, adjusted the door arm, manuall vented selenoid, etc. BUt accompiying my low tranistion is low boost on primary and seondary in 1st gear. The other day I "T" the line of pressure going to my TCA, and some sight says it shoudl iummediaetly jump to >7psi, mnine jumps to a little over 4 for sec, then to >7, ie 10. I don't knwo if this is a rpoblem yet, but will see.

3rdgenowner

My problem is similar but my second turbo will drop to 2 pounds and back up to five and never goes past 5 pounds, ever. This really sux. The car is currently sitting at PFS and they are dickin me around. I had an appointment on Monday and I called them today and they said they couldnt get to it for another couple of days. Excuse me but what does APPOINTMENT mean??? Oh well, when they tell me what is actually wrong with it I will post it and maybe give you guys some ideas

AdamP

Puma,

I have the same problem. Please let use know what they find if anything. Thanks

Adam Perrins

puma

iTrader: (2)

well, it is kind of weird, i replace a cracked hose and then it came back. I went on the higway and it worked, when i was coming back, nothing was working again. I will tear the car apart for another time and if it is not that, i will check the solenoid. I am confident though, i have seen it work. It looks like when the car is too hot, it stops working

suganuma

last night at my profec setting for 10# i saw a pattern of 10-5-10 - slowly, drops to 5# at 4500, but then is back at 10 by 5k. seems like still a low transition though.

so according to what ive read above, this is a turbo precontrol problem.

is it possible to test the actuator with an ohmeter? if so, what readings SHOULD i see??

and also, how can i check these check valves? just by making sure that they only blow through one way?

ive never had a boost problem, so im not really sure how to go about diagnosing all of this.

thanks in advance for the help

Nic

puma

iTrader: (2)

WOOO you revived an old topic

to test the check valve, yes, you only have to be sure that it flows only on one way.

puma

suganuma

what about low transition?

its at 5/6 no matter what boost level im at (tried 10 and 12.5)

definitely precontrol? what resisitance should i see across the connections on the solenoids?? i checked them both today with an ohmmeter in hopes that someone has numbers for me to compare them to.

thanks