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-   -   need some help on boost problem (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/need-some-help-boost-problem-131835/)

njm Nov 10, 2002 08:25 PM

need some help on boost problem
 
ok . i still have this boost problem . the car will not boost more than 6 lbs , both on the primary and secondary turbo . i have serched the data and perfomed the tests for the air bypass valve , charge control valve, checked all 3'' hoses along with 1'' hoses. i have checked the 3'' rubber couplers also . i have checked engine codes and found nothing .i have removed the intake and inspected the small vacuum hoses. i have tested the check valves and the one ways. i have tested the vacuum and pressure chambers . still the car wont boost past 6lbs. please help . thanks

Trexthe3rd Nov 10, 2002 08:29 PM

Check the 3 control actuators. You can only see them from the bottom. Especially the wastegate control actuator, there are little c-clips use for attachment and they are know to fall off.

njm Nov 10, 2002 08:37 PM

thanks for the tip . i will check those next .

johnchabin Nov 10, 2002 09:53 PM

You don't mention checking that the pills exist in the wastegate and precontrol lines.

Also, the plugs to these two solenoids may be switched.

majikeye Nov 10, 2002 10:41 PM

pill ?
 
i know i should already know this, but what are the pills?

Trexthe3rd Nov 10, 2002 11:21 PM

The pills are basically airflow restrictors. They look like a metal ball with a small hole and sits in the vacuum control line to the wg and pre-control.

majikeye Nov 10, 2002 11:25 PM

what is the vaccum control line? is it the metal pipe that the hoses come off of to the solenoids?

Trexthe3rd Nov 10, 2002 11:51 PM

There are three major turbo controls. The wastegat, pre-spool (pre-control), and turbo control. Each one is a pneumatic actuator controlled by a solenoid. The rubber hoses that goes from the solenoid to the actuators is where the pills sit.

johnchabin Nov 11, 2002 07:52 AM

I mentioned this as you will see this exact boost pattern if you are missing the pills or if the Turbo Precontrol & Wastegate Control Solenoid plugs are switched (or the hoses are switched).

http://www.rx7turboturbo.com/robrobi...controller.htm will give you good pictures of the two lines I am asking about. His example uses manual valves for restrictions, but you can use (like me) holley carb jets. If you use jets (or pills), the hoses can, of course, be much shorter.

The pills do not typically sit between the solenoid and actuator. They are normally between the primary turbo outlet and the actuator.

njm Nov 12, 2002 08:16 PM

thanks for all the help. the pills are still in the lines and the plugs are not switched . the car was running fine before this happened . it was abrupt and unexpected . it still will not boost over 6 lbs . any other suggestions ???

13brv3 Nov 12, 2002 09:19 PM

With all you've already done, you've probably seen this site, but if not, check out- http://home.istar.ca/~dvandit/turbocharger.htm

There's a ton of good info there. It sure sounds like you have a leak. Here's a good idea that P'colaFD mentioned in another post. This would really let you know where you stand.

(previously posted by Danny)
--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.

Aside from that, make sure your actuators are actually working. In other words, get a vacuum/pressure tester and use it to work the actuators.

Good luck,


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