trekmtbr89

iTrader: (1)

Been having a troubling boost issue for some time now. I've been slowly getting it better and better from where I originally started which was no boost at all. The boost pattern is as follows: 5ish - 10 - 10. It really struggles to build the 5ish psi on the primary, but once 4500 rpms comes around, it rockets away. I can hear an audible leak (whooshing sound) coming from somewhere up near the passenger side engine bay. My idle is between 1500 (cold), and 1100 warm, and sometimes hunts when I bring the car to a stop when it's cold.

before I go any furthur, here is what my setup is:
fresh rebuild, 3k miles on it, stock twins (checked for play - they checkout good, no smoke) I have an enfini y-pipe/coupler, greddy type-M front mount, and Apexi dual fannel intakes & filters.


Things I have done: KOKO (http://www.fd3s.net/boost_problems.html)

step 1. CHECK
step 2. CHECK (note: I have a removed double throttle)
step 3. PASS (vac is approx 16-17hg at idle)
step 4. FAIL (I tried this a couple times, I could get is to 1 or 2psi, but it took almost the entire RPM range to do so) also I did not see the Turbo precontrol actuactor move.
step 5. FAIL (I know there is no point going forward if you fail the pervious step, but here were the results) holds vacuum, and CCA works every time, TCA did not move. (also compared the screw length to a spare CCA to ensure the door wasn't slightly ajar)
step 6. PASS (holds pressure)
step 7. FAIL (5ish-10-10) boost pattern - very sluggish

Things I have done: VACUUM DIAGRAMS
I've been over and over all of the hose diagrams, replaced all hoses with new hoses, including the larger hoses, I even have a spare vac rack, and have everything labeled, I've tested the flow of air to every place correctly. I fully understand the flow of pressure and vacuum within the rack.

Things I've done: New Wastegate, Pre-control solenoids
(front of manifold), replaced these because they were damaged during my rebuild.

Things I've done: New throttle elbow to body gasket

Things I've done: Checked the CCV, and the Bypass valve - currently running with a CCV in place of the Bypass valve - I switched this during troubleshooting


I think I've narrowed my possibilities down to a couple things.

1. I have overlooked something very obvious on the vac diagram - been over this countless times (not likely - but possible I guess)
2. I have a primary turbo/manifold exhaust leak
3. I have a broken solenoid(s) (most likely turbo control)

Before I take out the vacuum rack and start testing toasty solenoids with a mityvac and 12 volt, I was wondering if anyone could give me any suggestions regarding my problem. Does this sound like solenoids? - the fact that the precontrol actuator, and tca don't move surely suggest so. What is their inert state? are the closed? or do they have to be closed by the actuators?, would it be possible for me to wire these closed to see if I can generate primary boost? If so It would be a quick answer to what is wrong.

again, any help is appreciated.

Thanks again.

rash_rvg

iTrader: (1)

Did you check the "throttle body" in the Y-pipe? Like, is it closed and not stuck open?

If you can build pressure up top rpm but not on the "primary only" rpm band, sounds like you are "stuck" with running both turbos at the same time (but without being a non-sequential conversion that is)

There isn't that many things that can go wrong for the primary not to do boost..... the transition and 2nd are usually the problem.

trekmtbr89

iTrader: (1)

I think you are referring to the Charge control Valve, and yes, the screw adjustment has been checked to make sure it's closed, and during the KOKO test, it does open at 4500RPM

rash_rvg

iTrader: (1)

went up and read everything more carefully.
You're saying that you pass step 3 and fail step 4?
Step #3 Primary Turbo Inlet
Step #4 To/From Intercooler

?! Is this correct ?!

Seems weird... You got a cat inside your IC or something? :p

You also say that you don't see the Turbo Pre-control Actuator move. How are you testing this exacly? KOKO ?

trekmtbr89

iTrader: (1)

The steps refer to the KOKO test which is a little furthur down the page on that link almost all of the other stuff on the top has been tested - I don't have any of the stock intercooler couplings anymore, everything is metal piping from air cleaners to throttlebody.

Also, while testing the actuators, during the KOKO test, I setup a video camera under the car and videoed the actuactor while I performed the KOKO test.

trekmtbr89

iTrader: (1)

I think my aftermarket intercooler couplers might take some of the blame here...I"m going to replace them and see what happens. a leak in the intercooler hose - would that create a high idle?

dgeesaman

iTrader: (7)

Have you hooked up your mityvac directly to each actuator to see if 1) they operate with a reasonable amount of pressure/vacuum and 2) they have internal leaks?

Another point: you can do the KOKO test immediately after a short drive where you generate boost to charge the pressure tank. The fact that you're not getting boost in neutral is not necessarily the end of the world. So at least after a short drive you can verify the pressure system holds pressure and establish if the TCA is moving in operation.

David