Someone is always having boost problems with their FD, so here's my contribution. If you're having problems, and need help, you need to post as much information as possible about your problem. Not just "My car feels slower than it should. Are my turbos shot?" If you haven't already seen this site, then go to it: http://home.istar.ca/~dvandit/turbocharger.htm it is incredibly informative.



--First off, Get a boost guage. It doesn't have to be anything fancy. Auto parts store have them for less than 40 bucks. Find out what your boost pattern is in third gear.



--Another thing is, if you haven't done the silicone(or viton or regular rubber) hose job, you might want to go ahead and do it. It's sort of like a right of passage for FD owners.



--If you have low boost on both turbos then you might have a boost leak. I've found that the easiest way to find boost leaks is to take some soda cans or tennis balls or anything of the like, and put them in the intake hoses(from the airbox to the turbos). Clamp the hoses tightly around the cans. Next, get a blower nozzle for an air compressor that can have a vacuum hose slip on. Put the vacuum hose on the blower nozzle at one end and an intake nipple at the other end. Tighten the vacuum hose down with hose clamps at both ends. Turn the car on(not the engine though). Now lightly blow air into the intake with the blower. The air will have no where to go except where the leak is.



--If you have good primary boost, but not good secondary, then your problem could be related to several things: charge control, charge relief, two turbo control solenoids going to the TCA, the precontrol, and possibly a clogged cat (Let me know if I left something off).



--To check for secondary problems, "Tee" into several vacuum lines. To do this, get a three-way vacuum "Tee" and put it between the nipple and the hose which attaches to the nipple, with the other hose going to your boost gauge.



--"Tee" into the line coming off of the Y-pipe between the secondary compressor and the charge control actuator. It should start making pressure around 3,000 rpm. Above 4,500 and above there should be at least 10 psi at that nipple. That shows exactly how much pressure the secondary turbo is making.



--If there is 10 psi at that nipple all the way to redline, but there is not 10 psi seen at the extension manifold, then you might have a problem with the charge relief valve. "Tee" into that line and see if it is getting vacuum before 4,500 and pressure after. Also make sure that the charge control actuator is seeing the same values. The CCA and CRA use the same pressure and vacuum sources.



--It is also important to check the pressure tank and vacuum tank's storage ability. Just pull of a hose going to the pressure tank and listen for air leaving. For the vacuum tank, with the key on, pull off the hose to the CCA. Air should be sucked in.



--If you don't hear your turbos switching over at 4,500 rpm, then you might have a problem with the TCA. There are two nipples on the TCA, one for vacuum, and one for pressure. Make sure they are seeing the appropriate values.



--One common problem is for the turbo control solenoid for vacuum, which is attached to the ACV will get affected by the heat of the engine, and will intermittenly fail when the engine is hot, showing sluggish transition.



--Finally, don't be afriad to ask. If you give us enough information, we can be pretty helpful. Just be willing to get under your hood (and possibly under your car) and get your handes dirty.



Sorry if this is too long, I just figured I would sit down and do something somewhat helpful. Feel free to add to, or correct any of this info.

--Danny

heres my 2yen.

1. you need to be clear on wheather the secondary comes online with low boost or it doesn't come online, with low boost.

2. if it doesn't transition, the most likely culprit is the hose on the white solenoid under the plenum, or a line blown off the pressure tank

3. i dont agree with the hose job; it usually ends up doing more harm than good, and most of the hoses are under vacuum, and are not going anywhere. there are about 10 hoses that need to be tied off/replaced and your done.

4th pay attention to your car! you need to know if it doesnt feel right, or theres a new noise etc



mike

i have a problem with my primary boost. i have slow spool up and can only make a maximum of 7psi and this is with running 90% duty cycle to the turbo pre-control actuator https://www.nopistons.com/forums/pub...IR#>/blink.png the pills are still inline, the vacuum and pressure chambers hold thier charge...



what are your suggestions?

btw, orginally used AVCR to control pre-control and wastegate actuators (which eliminates any problem with pre-control solenoid). now i'm controlling WG actuator with AVCR and pre-control with stock solenoid through a Power FC



i have 2 theroies



1. CCV is staying open and therefore primary charge is exiting through th Air Bypass Valve

2. pre-control door is slightly ajar

Great info but that link doesnt work......

https://www.nopistons.com/forums/pub...1047683358.gif I just rebuilt my 93 FD 13-B Motor and am have a secondary turbo boost problem.

Primary turbo waste gate is controlled by a "ProFec-B. Blitz Turbo-Time/Boost gauge is used to monitor boost at the Upper Intake Manifold. Vacuum port used is the rear one of two located on the outboard side of the U/I facing the passenger side shock tower.

Turbos are BRAND_NEW OEM from Mazda.

Boost Actuator, "Large Can" mounted/bolted under turbos is original to the car and has approximately 113K miles of use. Engine rebuild was done by my son, "GoodfellaFD3S" (that's his login name on the RX-7 forum). I reinstalled all the external engine appliances and dropped the engine in 2 weeks ago (30Oct2007).

The problem is this:

Under part throttle, I get normal boost from the primary turbo, i.e. .85Bar. If I floor the pedal and apply WOT no transition to the secondary turbo takes place at 4500 RPM mark. Boost readings drop-off to around .40 to .25 Bar as RPM increases above 4500RPM.



The Engine wire harness is NEW OEM harness purchased from Malloy Mazda (Ray Crowe). All solenoids in the "rats-nest" are original to the car as well. The Siamese solenoid attached the U/I in the front and the other solenoid tucked in under and also bolted to the underside of the U/I were replaced in the last 5 years.



All vacuum lines are silicon, (replaced several years ago prior to this latest rebuild) and the system had functioned normally prior to engine removal.



I'm was pretty sure I'd hooked all the lines correctly, however that doesn’t seem to be the case; i.e. since no transition is happening. I’m also wondering what else isn’t hooked up in its’ correct location.

Does anyone have a GOOD chart that shows exactly where all the lines are supposed to go??



I also have detailed close-up photos I'll try to post up of my "Happy-Tray" and the waste-gate and Pre-Control vacuum lines. Hopefully there’ll be enough visual detail for someone familiar with the sequential setup to see right-off what I screwed up.



I can be reached via e-mail @ karken49@optonline.net or IM... AOL=karken29 and Yahoo IM = "karken_07960.



Thanks ahead of time for any help.

Good luck with all your sequential problems! God knows I have had my fair share of them! https://www.nopistons.com/forums/pub...IR#>/wacko.gif



That link doesn't work. Here is a website I have used in the past.



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



Wish I could help. I know nothing about fixing those damn Hitachi twins. Thats why Dave does it. https://www.nopistons.com/forums/pub...#>/biggrin.gif

https://www.nopistons.com/forums/pub...DIR#>/cool.gif

Hopefully you have found the problem. I can't stand to have my car not running (well it runs with blown turbos but it sucks to drive lol) Let us know if you are able to fix it. Taking pictures of the whole ordeal could really help someone else with the same problem. Thank you for that link! I bookmarked it a long time ago but couldn't find it when I needed last month. https://www.nopistons.com/forums/pub...IR#>/wacko.gif



Dave of Speedmachine btw. They have helped me sooooo much with my car. https://www.nopistons.com/forums/pub...IR#>/happy.gif