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-   -   secondary boost problem (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/secondary-boost-problem-1017719/)

FC3Sdrift 11-14-12 01:00 PM

secondary boost problem
 
I've been searching for awhile trying to solve my boost problem.
Its had problem since I got it, I bought a new turbo control ,prescroll and wastegate
solenoids and redid my vacuum lines. I just rebuilt my engine got it broken in, and I still am having problems. Im going to get the check valves but I checked mine and they were all good, I put a different one on the pressure chamber and it hold pressure I havent hooked my boost gauge in there yet.

My problem is I get 10-6-7 boost pattern, In my searching I read that if the plugs for the WG and Prescroll were backwords you would get a boost pattern like that, all the wrap had broke off those wires so I figured maybe I had them backwords, I tried switching them and got 10psi from the primary then it spiked to 15psi with the secondary before I could let off.
So now im more confused than ever, I dont know if I have those plugs backwords and I have a WG issue , or if maybe the turbo control solenoid down on the vacuum rack is bad

my exhaust set up is 3"hks dp, custom midpipe with hf cat and resonator to apexi n1 catback, I ported my wastegate while it was apart too

Reno_NVFD 11-14-12 03:16 PM

You could also try some of the other FD websites like this one

http://www.fd3s.net/boost_problems.html

RevenSeven 11-14-12 04:34 PM

I'm having the same problem. Please keep us posted if you fix the problem.

FC3Sdrift 11-15-12 12:48 PM

IChecked the FSM the wire color for the Wastegate plug are blue with white stripe and black with white stripe , the prescroll is the same but the blue wire has a yellow stripe. I did have them backwords, so now I have to figure out whats goin on with my WG, maybe my restrictor pill is blocked , Im going to toss on a MBC in its place and see if that helps. I also Fixed a pretty big boost leak at the Y pipe.
I have to go to work soon hopefully I can warm it up and take it for a rip around the block

the boost spike might have came from the cold weather?it was only 6celcius out

FC3Sdrift 11-15-12 01:36 PM

i did a couple partial throttle pulls it was goin to around 10-11psi after the transition and I would let off so i dont know if it will keep goin up. Im going to wait till I get that mbc on there. its at my shop and i dont have time to run there today

FC3Sdrift 11-16-12 06:40 PM

so I put my mbc on, its a turboxs bleeder type, but i still had to block the line to the wastegate.
after getting the mbc dialed in It holds a solid 10-5-10 boost pattern with no spikes.
so i guess i'll start looking at the ccv and prescroll systems.

I still think i need to check the turbo control solenoid down in the rats nest i dont want to pull the uim off yet

RotaryEvolution 11-16-12 09:23 PM

did you perhaps miss putting the pills back in the lines between the actuators at the charge pipe? common problem when people start replacing vacuum hoses without knowing they are there.

FC3Sdrift 11-16-12 09:37 PM

no i reused the old lines but i made sure the pills were in there.
I was watching a video i made with my gopro , I can hear faint mooing sound when i would boost a bit on the primary. so air is leaking from somewhere
which vacuum chamber stores the charge for the prescroll? the one by the uim?

RotaryEvolution 11-16-12 10:42 PM

i honestly can't remember at the moment, the FD system is quite busy to remember everything on. iirc the charge canister sits on top by the IC pipe and the vacuum canister is the larger one sitting on the front cover. i say that because the large tank on the front cover is usually sucked in to some extent.

but your turbos are transitioning fine it sounds like, just the wastegate isn't holding closed like it should.

the moo sound is probably just from the smog pump, an air rushing sound could indicate that the primary turbo is pushing some air through the secondary turbo when it shouldn't. start by double checking your vacuum lines that pass through the lower intake manifold that control the secondary turbo butterfly, even though your primary sounds like it boosting fine. if that butterfly isn't opening properly you will have low secondary boost.

RevenSeven 11-17-12 05:00 PM

sorry for adding my problem onto this thread but since i'm having the same problem, I didn't want to start a new thread.

I'm also boosting 10-8-6. When I hit about 5k rpm I hear a loud whistling sound coming from the intake/turbo area. I'm using the greddy airnix intake and I thought the sound might just be the air rushing through the aluminum intake pipes causing it to whistle but I figured I'd ask to see if that is normal. The whistling sound is ear piercing from the outside of the car. Is this normal or does this sound like a leak coming from somewhere?

It does not whistle when it is in full primary boost. Just when the secondary kicks in. The primary turbo intake is plastic but the secondary intake is aluminum.

Could it also be a bad secondary turbo? The odd thing is, I had stock turbos with the same intake and setup, it was boosting 10-8-10 and it still made the whistling sound. I am currently using bnr stage 2s. Both turbo setup gave the whistling sound.

thanks for you help!

RotaryEvolution 11-17-12 05:11 PM

make a cap for the secondary turbo inlet and an adapter for the primary, you should do a pressure test of the system to check for leaks.

FC3Sdrift 11-17-12 10:45 PM

check for leaks at the vacuum lines around the pressure tank check the wires to the prescroll and wastegate actuators
prescroll is blue/yellow and black/white wastegate is blue/white and black/white

I was messing around with my car today I fixed a few things, the vacuum line to the charge control actuator was really loose, i could spin it easily with the spring clamp, so i replaced that, last night I had this crazy idea that drilling out a pill for the prescroll would raise the transition boost when i was taking the old line off i noticed that my prescroll actuator was loose so i tightened it up and tossed in the drilled out pill, took it for a quick test drive, and obviously it lowered my primary boost lol (thats what happens when you're thinking about your car at 2 am hahaha) anyways I can hear it prescrolling alot louder now like before, and my transition is alot faster almost instant , you can hear the differance when it kicks in , I was getting 8-6-10, so Im thinking if I swap in the original pill in the prescroll line it will work properly, I think the prescroll actuator being loose wasn't allowing it to fully close the door.

I'll have to try it out tomorrow

FC3Sdrift 11-18-12 09:36 PM

swapped in the original pill into the prescroll line today, and im still having the low transition, sob lol

I'll have to pull the uim off this winter and check the solenoids on the vacuum rack, and get some daleclark check valves . Im just glad I got my new engine broken in before winter

AzEKnightz 11-19-12 11:17 AM

Maybe it's time for an upgrade solenoid system. PM if you are interested. You can get rid of those transitioning problem IF the solenoids are the cause.

-AzEKnightz


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