Hello,

I have a sequential problem.

My Boost pattern is 11 - 7 - 7

About my car.
Got a Full 3 inch exhaust.
V-mount kit

My RX7 is a Series 7, so I have a solenoid box and integrated restrictions for wastegate and precontrol.
I have tested every solenoid and replaced every defect with a new one. I also tested every check valve.

What I've found out so far.
I have connected a boost gauge with a T to each line and have driven.
Charge Relief gets vacuum until transition, then atmosphere.
Charge Control gets vacuum until transition, then boost pressure.

Turbo Control actuator works. The actuator gets vacuum at the front back during transition. I put myself under the car and checked the function. He's moving fine.

I looked at the Precontrol with a T, it works.
I tested the Precontrol Wastegate with a pump, it's not jammed.
I tested the wastegate with a pump, I'm not jammed.

I checked both pressure tanks. The first one keeps pressure for over an hour, the other one holds vacuum for over an hour.

I have tested both BOVs, both are perfectly tight.

Do you have any more ideas for me to consider?

Many greetings
Bastian

 

I would suspect a boost leak first. Even a small leak can really add up, especially up top.

I would also check general things like making sure your throttle cable is adjusted so when you floor the pedal in the car it is actually opening the throttle all the way. Also, make sure you have happy spark plugs.

T'ing the boost gauge into solenoids to test is one of my favorite troubleshooting techniques that no one seems to do, it really does make tracking things down so much easier.

Dale

 

Hi Dale,
throttle cable is fine. Also checked it with my aftermarket ecu (adaptronic select, but dont worry, all the troubleshooting is done with OEM ECU )
Plugs are New also as cable. A leak between turbo and Throttle? But why can I make 11 PSI in first turbo?

I Teed everthting and cant finde something ;(

 

Did you check the electrical connector for pre-control and wastegate solenoid. More often times it gets over looked and the connection are switched around. The connector with the white dot should connect to the solenoid with the white dot.
https://www.rx7club.com/build-thread.../#post12151834

 

Yes i checked them. I'm using a aftermarket ECU for checking the solenoids where I can activate them to check if they are connect correct

 

do a boost leak test by pressurizing the system

 

whats the best way to do such a test?
And i can make if I want 1 Bar pressure wich high DC% before transition on first turbo. Is this possible with a boost leak thats drops pressure to 0.45 bar after transition?

 

Boost leaks are sneaky, they will do some weird things. You'll need a compressed air source, regulated to around 10-15 psi. Remove the intakes, cap them off (I usually just double over some thick plastic bags and hose clamp them on) and find a hose or fitting you can hook the air line to. Pressurize the system and look, listen, and feel for leaks. Using your hand to feel the escaping air is usually the best way.

Another possibility is a restriction in the exhaust or a restriction in the intake.

Dale

 

boost leak tester example for a twin turbo Nissan 300ZX

https://www.z1motorsports.com/z1-pro...er-p-1867.html

you can make your own with hardware store parts too. it's basically a PVC cap with an air hose fitting, connected to the turbo inlet by a rubber coupler and hose clamps. you don't really need the gauge, you can look at a boost gauge in the car or wherever (even at the MAP sensor).

here is a write up on pressure testing a Subaru (single turbo) HOW TO BOOST LEAK TEST


when you pressurize the system, take a spray bottle with water and a small amount of soap in it. When you spray the soapy water you will see bubbles where the air is leaking.

 

I'm not sure will an aftermarket ecu check if they are plugged into the correct solenoid, I could be wrong, from what I can recall they only check for system faults (Resistance and voltage signals threshold). My PFC wasn't able to detect the issue with sensor check screen. For the wastegate and pre-control, it is very easy to access, just remove the pressure chamber by the cross over pipe and you able to see it. Best double check physically.

 

He's saying he can manually trigger the solenoid in the ECU, then go under the hood and inspect operation to confirm it's plugged in and behaving as expected.

 

Have you inspected your secondary turbo to verify it spins freely, has no shaft play, and that there's no oil leaking, etc?

 

One other thing I just thought about -

One of the guys here had boost issues, he had the earlier N3A1 twins that have more of a tendency to crack. There was so much cracking around the waste gate flapper it was letting a lot of exhaust energy around the waste gate, resulting in low boost.

Dale

 

No but i can tick "invert" wastegate. And if the right one clicks, i know the plug sticks on the correct solenoid.
I changed all hoses to silicone 3 years ago and was driving fine till it stopped working. I will remove the solenoid box on the weekend and will pressure check all valves

 

So i checked all my solenoids.. And almost all are gone! 2 Are Working but veeeery slow an weak when hot. All others are leaking or dead when hot, or dead all the time. Is there a aftermarket solution for this?
I'm driving simplified sequential now. so is it possible to change alle solenoids against MACs?

 

If you're going simplified sequential, and if any of the emissions related solenoids are good, you can swap them in. Or, get the solenoids new or used.

There are aftermarket solenoid projects but IMHO I'm not a fan of them. The stock ones do a good job and are clean, problem is heat, oil, and time gets to them.

The MAC valves are only for the 2 boost control solenoids. They will only work right with PFC.

Dale

 

I'm driving a adaptronic, so no emissions related stuff is active.

Why will MAC valves not work for charge-control, charge relieve und turbocontrol vac/press ?
They are also 12 volt valves like the OEM ones and are capable of PWM?

 

How much is a new OEM solenoid box for the series 7? It has to be possible to get one somehow. There's no way Mazda has made those no longer available considering they were in production through 2002.

You could use the MAC valves... but IMO re engineering the system is just unnecessary when the OEM part will work. It failed after 20 years, so buy a new box and it will last another 20 years.


RHD Japan looks like they have a box:

https://www.rhdjapan.com/mazda-oem-k...sing-fd3s.html


that's about $320 Euro, and I think that's a brand new OEM part. Maybe you can email them to confirm. That has new check valves in it too, assuming it actually is a new part. So yeah it will break again, but as I've said before, your brake pads wear out too don't they?

 

I believe the solenoids in the "black box" are replaceable, the two halves come apart. Mazda used those newer solenoids in tons of cars, I've seen them in the junkyard here in the US on other 90's and early '00s cars.

May be money ahead to replace the whole thing, hard to say.

Dale

 

Oh, the MAC valves are way overkill for replacing a solenoid. The solenoid is an "air relay" - it has 3 ports and with 12v applied it changes where the air goes to the ports. They just click open or closed with 12v. The MAC valve is duty cycle based - how much of a duty cycle it is given will determine how open or closed it goes.

Dale

 

$350 (plus shipping of course) and he probably never has to worry about it again for as long as he owns the vehicle... sounds like a good deal to me.

 

Thanks arghx for the link, but as i said, im driving a adaptronic select ECU which has no outputs to control the emissions solenoids, Why should I pay for a whole box if 70% of it isn't used by this ecu. Only 3 Valves of the Box are for turbocontrol. The other 4 are. Fuelpressure Regulator(), 2 x Split Air(ACV) and Doublethrottle

DaleClark: Yes they are replaceable. I got two boxes here and parted them both out. But both had just leaking or sticky valves. One new valve is about $20 @ ebay. So with about $140 you can repair the box. But as I mentioned before. I'm driving simplifed sequential.
Here is my setup with 3d printed mounting plate for solenoids: Worked fine. till yesterday when another valve died..
Next week I will replace alle of the valves with new ones.



Simplified Sequential, 3d printed

 

You're not paying for the box.

You're paying for not having to deal with it again.

To me, that's worth the money. To others, maybe not.

 

My solenoids are now all working, my pressure and vacuum tank are holding the pressure perfect over days.
Charge relief, charge control, and turbocontrol are working.

Also T'eed in all vacuum lines again and everything works as it should, except the boost pressure on the second turbo

I raised the WG DC% to 60 % which makes great boost on first turbo: 180 kpa
After transition again only 145 kpa fixed.
Any Ideas what it else could be? Maybe "just" a broken turbo?

 

Got a diagram of how you've got the solenoids plumbed?

Should be like this, minus the bits you've removed.

S7-8 System Diagram by Tom Kinsman, on Flickr