nismosilvia270r

iTrader: (5)

I have been trying to troubleshoot sequential twins and after much research and testing.

BLUF: Precontrol solenoid connector swapped with Turbo Control Vacuum solenoid connector.

o Symptoms:
- 7psi on primary
- slow transition (if any transition at all)
- twin boost bleeds off
- "MOO" sound
- boost resets after RPM drops below 3000
- 4th gear, the RPM climbs slow enough for the Precontrol to trigger the Turbo Control Vacuum solenoid "properly"
- when twins work in 4th gear, boost spikes to 13psi
- KOKO test looking for CCV and TCA movement. (CCV MOVES ONLY)
- TCA moves instead of Precontrol Actuator does not move when revving in neutral looking for 4+ psi. (THIS SHOULD HAVE BEEN THE CLEAR SIGN THAT SOME CONNECTORS WERE SWITCHED)

o Diagnosis
o With all of these symptoms at once, I did the following diagnosis techniques:
- Primary Turbo diagnosis and replaced the SMIC pipes with HKS hard pipes. (NO CHANGE)
- Replaced all hoses from the y-pipe down to the actuators with silicone. (NO CHANGE)
- Tested check valves, air tanks, and CRV / ABV.

o Read that sometimes the Precontrol and Wastegate plugs get switched.
o Tried switching Precontrol and Wastegate plugs. Led to these symptopms:
- Primary boost shot up to 11psi
- Slow / Fluttering / Hesitating transition
- Twins boost 14 psi until letting off the throttle
- Letting off throttle causes boost to bleed off, won't build boost, and "MOO" sound again.

o Final Solution
- Found a thread with people arguing over the wire colors for Precontrol and Wastegate and which connector has a DOT on it, etc.
- Turns out wire colors are similar, L/Y and L/W, respectively.
- I check mine and I have, Y/L and L/W.
- Removed the PW solenoids... lo and behold there sat the L/Y plug attached to the TCAV solenoid.

After switching the plugs back to correct solenoids I saw 13psi from 2500-7500 RPM with a very fast transition.

Very happy with results, but unfortunately it took so dang long to figure it out.

This may not be the solution for everyone, but its worth a look since the three solenoid plugs are very close to each other and look very similar.

worth noting my mods on stock engine/ecu:
- Fighters intake
- HKS SMIC Hard Pipes
- GReddy Downpipe
- Silicone hoses

Please, no comments regarding the HIGH BOOST LEVELS on stock ecu.
- I felt it necessary to note the boost levels attained with the mod list for curious readers.
- I've since replaced the Pills with adjustable needle valves to bring the boost down to 10psi.

seven1997

iTrader: (2)

What are the PW solenoids you removed? Not familiar with the PW acronym!

seven1997

iTrader: (2)

Oh sorry ! I You meant the precontrol and waste gate solenoids connectors!

seven1997

iTrader: (2)

L/Y what does this mean? something /yellow? same with L/W
I am confused!

oyvindjs

iTrader: (4)

its the wire color coding. Look at the start of RX7 electrical manual, it should be listed up there

TEDDER1

iTrader: (1)

My first FD did that yrs ago. It ended up being the little 30cent c clamp that connects the actuator arm to the flapper between the turbos controlling the amount of exhaust flow.

It would boost through any gear fine but not reset for the next making the mooo sound.

So if it isnt that it might be solenoid for the actuator.

MOBEONER

iTrader: (18)

I have a better solution.......... Single turbo ......................... Joking

nismosilvia270r

iTrader: (5)

L/Y = Blue/YellowStripe
L/W = Blue/WhiteStripe

I bought the car from the original owner and it only has reliability mods done to it. It a super clean, stock car that I want to keep that way.

Mazda designed it to perform from the factory, who am i to mess with that? haha

oyvindjs

iTrader: (4)

Mazda designed it to perform with technology from 1992, that had to work with the fact that alot of car owners dont want to poke around in the engine bay, so there has to be compromisses all the way
This is 2012, and reliabilitymods do work

nismosilvia270r

iTrader: (5)

exactly. my comment was in reference to the single turbo option.

and the rx7 isn't a civic (totally worthless in stock form), so i don't mess with what works.

billt

iTrader: (1)

oyvindjs- "Mazda designed it to perform with technology from 1992, that had to work with the fact that alot of car owners dont want to poke around in the engine bay". Yeah, and they also had to work with the fact that a lot of Mazda mechanics just never knew how to poke around in the engine bay of an FD, LOL!

nismosilvia270r

iTrader: (5)

Update.

Problem: the needle valves i used in place of restrictor pills started to leak, and the actuators weren't opening at all.

Solution: since i had replaced the check valves on the car, I had some spare viton check valves, aka DaleClark check valves.

I simply cut the nipples off of each end of one check valve, slid one nipple in place of the each of the restrictor pills, and clamped the hose around them.

Brought the boost down to 10psi across the board.

With Reliability Mods done to car:
Stock Restrictor Pills resulted in 13-12-13 boost pattern
Viton Check Valve Nipples resulted in 10-10-10 boost pattern

nismosilvia270r

iTrader: (5)

Also, worth noting that with no restriction at all in the precontrol and wastegate lines:
- primary boost <7psi
- no transition
- secondary boost bleeds off
- moo sound
- need to lower RPM below 3000 to reset