Hey guys, just looking for some help. I just got around to finishing a full turbo swap on my 91 NA with 54,000 miles on it..

I pulled the running t2 motor and everything else out of a donor car, did the rats nest removal, blocked everything off except the BAC, I'm running an RE-Amemiya Redom ecu. I kept my boost control solenoid as well.

The car is running strong, making tons of vacuum, idling great..butttt my issue right now is my car isn't going into boost. Close to redline I'm still making vacuum, (not a lot at this point). I've already checked the wastegate flapper but it's free and working. I almost positive I don't have any boost leaks either....Any ideas?

Unfortunately I can't check codes due to my ecu being from a JDM car.

 

what are you using to measure your boost pressure?

 

A blitz mechanical gauge

 

is the turbo any good? these cars arent complex like the fd. basically if its not boosting its either the turbo isnt physically spinning for one reason or another, or there is a huge vac leak. its possible your bov is leaking or super loose. does it sound like your turbo is spooling? can you hear the bov actuate?

 

I just took it around the block with the wastegate line capped and it was building boost..so I must have a messed up boost control solenoid?

 

If the solenoid is bad, the car will still build boost, but the solenoid won't bleed off the pressure to allow the boost to go higher, unless it's open. Bypass the solenoid. Just connect the 2 hoses on the solenoid with a plastic connecter and give it a try. Those solenoids work themselves to death, especially with an aftermarket ECU to raise the boost. If it is the solenoid, disconnect the solenoild and add a MBC e.g. Hallman.

 

how did you have the boost control solenoid hooked up? It's basically tee'd off the compressor housing. Did you reverse the vacuum lines on the solenoid? One is inlet and one is outlet. Look at this diagram very carefully.



I wouldn't just ditch the factory solenoid yet. In my experience the Mazda OEM boost control solenoids are very reliable. The FD boost control solenoids rarely fail, although all the other solenoids on that car do.

 

I've been through 3 of them. On the stock setting, stock ecu, the OE solenoild lasted 15 years, but I've been through 3 of them since I installed the modified G Force ecu. They were used units, but checked out fine and operated properly for the time they were working, but the solenoids work themselves to death trying to keep the boost at 11-12 lbs. When the third one went, I installed a remote Hallman MBC.

 

so I wonder, right now on my s5 turbo setup I have that tee near the waste gate valve actuator capped off and it doesn't look like I'm overboosting at all. Where would you connect the other hose coming off the MBC?

 

between the actuator and the brass fitting on the coldside