Boost problems. Primary turbo is making oodles of boost, but when 4500rpm hits all boost is vented (boost gauge reads less than 5psi) Been fighting this for quite some time now and ready to give up.

I have checked all the vacumme lines I could think of.

Some history. I purchased the car 4 years ago. Replaced the engine with a Pettit street port. Upgraded the ECU through pettit as well. Replace down pipe mid pipe and stock muffler. Installed new 4 puck racing clutch and short throw shifter. Replaced all vacumme lines with silicone and zip ties. Changed over to cold air intake. Removed air pump. Replaced catch tank with aluminum. Running stock intercooler with upgraded hoses from Pettit and Greddy piping kit. The pills are in the lines a .060" and a 058". Things were going well and suddenly changed. I don't drive the car a whole lot. Tried to installed boost controller a while ago and no success so I was running it with the pills again.

I have switched the BOV and CRV and this made no difference. I have removed the check valves and they are working properly. The charge control actuator closes when the car is turned on and opens when it is off. The pressure tanks were checked and are not leaking. Turbo pre control and wastegate solenoids were checked with a 12v supply and the ports switched as they should. Actuator for wastegate, pre control and turbo control are all connected.


Please reply to my crisis and keep the explanations simple. I am fairly green with trouble shooting the sequential twin turbo systems.

 

Have you checked the hose that come off the part of the y-pipe from the secondary turbo ? This hose gets hard and cracks when hot it will leak lots of air

 

get two vacuum pressure guages.

Tee into the lines to the two control hoses at the swing valve in the "Y" manifold. go for a drive reading the guages. at 4500, in order for the door to open pressure on one side of the door must go to zero. on the other side vacuum goes to zero. the door will not open to admit the secondary turbo at 4500 unless BOTH of these events occurs at 4500.

you will see it on the 2 gauges. probably one side is malfunctioning. from there it is a simpler matter to trace the circuitry back to a leaking hose etc.

while you are at it Tee into the secondary turbo to see it is making boost.

howard coleman

 

I'll buy it for $2000.

 

check where your old bov are.. one of them poped off on mine before and all i heard was venting air and no boost

 

Viking funeral!

 

The Paul at AIM tuning changed one check valve in the rat's nest and it fixed the problem I had. The symptoms were identical to yours. Part price,$32.

 

I don't think this is an issue. I switched the two valves, went for a ride and had the same results.

 

Could the ECU have anything to do with the issues I am having.

 

Not likely.

Check the turbo troubleshooting page:
http://www.autosportracetech.com/RX-7/rx7stuff.htm

 

Going to attempt more trouble shooting this weekend using hints from the auto sport race tec guidelines.

Will post again after.

 

This is the exact place I would look. Change your one way valves on your vac. tank with new ones, NOT HELP! BRAND. The vac tank is the 7 sided box just behind the alt.

 

I had a similar problem in the past just like this. The primary turbo would make plenty of power, yet at the transition, i would loose all boost and would be like ~3psi. My problem was that i had a faulty solenoid that caused the pre-control not to stop functioning and continue to vent boost after the transition.

Hope this helps.

 

where did you buy the solenoid from and if it is here.. http://mazdatrix.com/b-egr.htm which one is it?

 

did you even read howard coleman's post? he just told you what you need to check. it is obvious that you are either venting all of the seconday'r boost... or the secondary is not coming online. He gave you a fix.

 

I'm with you, Monkman. He should do Howard's test first.

 

What is exactly happening is that when my turbo switches to the secondary at 4500rpm I hear loads of air being exhausted under the hood. Is it possible to know what causes this without teeing in to the lines. If not, how are the gauges run so that they can be seen easily. Are they usually just taped on the windshield or what.

I guess I am just trying to be lazy.

How about those vending machines anyway?

 

try checking the the wastegate. there are little "c" clips on the shafts of the wastegates. they may have rusted of or something. just something to check
hope it helps

 

To temporarily use a boost/vac gauge, run the line along the hard brake lines on the firewall and to the very end of the weather-stripping for the hood. Either hook it under the end of the weatherstripping or tape it down. Then just run it in through the window. I've used an old autometer gauge with the narrow, more rigid tubing and it works great (gotta watch the line when closing the hood though). Of course, it'd be safer to run it in through the passenger-side window and let a friend watch the gauges while you drive the car...


The forum can help, but you'll have to do the real work

 

I was having this exact same problem and it was that i had my charge relief solenoid and my charge control solonoids vacuum lines were swapped i put them back correctly and it all worked. So What i would do is check your charge control solenoid first.

 

Check that the check valve coming from the y pipe outlet to the pressure tank(on the front of the manifold) is oriented properly. The arrow should point toward the drivers side of the car to allow the pressure tank to keep pressure. If it is oriented the other way it will not hold pressure and won't allow the CCA to open, therefore making the secondary turbo prespool and boost gets blown off by the secondary turbo CRV. Also, if this isn't the problem, check to see that the hose that goes to the port on the electrical connector side of the Charge Control Solenoid(IIRC it is the second solenoid back on the rack and is white, this was the problem with my car when I bought it, but I got about 2psi of boost past 4500rpm and about 0psi by redline)
Art

 

Where in Mo. are you? I can swing by if you're close and take a look.

 

Just went and looked under the manifold with a flash light. I was poking around with a screwdriver, flipping hoses and guess what I found. The charge control solenoid as Art mentioned has a broken stem.

Now is there one I can use that is not needed. I remember Art saying something about not needing one of them now that my air pump is removed. Should I use it or buy new. (and if use it which color)

 

Tyler,
IIRC, we disabled your fuel pressure regulator(the orange one at the back. You could easily swap them out if you have the manifold off. The charge control solenoid is white. This IS why you aren't getting the proper boost. Give me a call dude. I'll pm you my number again if you need it.
Art