To make it short, I'm experiencing boost problems in my fd ever since a secondary injector install that I did recently. To the best of my knowledge and my rotary mechanics, all the vacuums lines were correctly connected to their correct nipples, and solenoids. The problem occurs strictly 1st and 2nd gear, when I go full throttle. The symptoms are that my primary turbo doesn't spool to the boost its set at which is .90 bar. Infact it feels like its barely boosting .2/.3 bar if that at all. There is relatively loud air wooshing sounds comming from the engine bay, yet i checked all the couplers and hoses and made sure they are all tight and fit, and the problem still persisted.

The secondary turbo boosts perfectly with no problems and pulls hard. Turbos arn't going out either as they have 32,000 original miles on them and never showed any symptoms of failing prior to this.

Can any sequential turbo experts give me a specific direction to go with, when I go to diagnose the vacuum lines, solenoids, check valves, keeping in mind that this problem is confined soley to the primary turbo boost.

Thanks

 

Two possible problem areas:

TCA - Turbo control actuator. It's controlled by two solenoids. If they BOTH aren't working properly, then the actuator will not be responsive.

Charge Control - It isolates the primary turbo during the first half of the boost pattern. During this time, the secondary turbo is venting the excess through the charge relief valve. If the charge control isn't working, it will allow the primary to loose its boost through the charge relief valve until it closes around 4000 rpms.

 

What is strange is that boost in 3rd 4th and 5th is perfectly fine in primary boost and secondary, but in 1st and 2nd the problem is prevelant. I would think that if the TCA wasn't working properly, or if the Charge Control wasn't, that i would have the boost problem regardless of what gear i was in...? Is this not necessarily true?

 

Not necessarily. It sounds more like a TCA problem after your last description. Since the TCA requires both vacuum and pressure to work properly, problems are more noticeable in the lower gears as the actuator needs to operate more quickly due to the gearing. The higher gears mask the issue since it doesn't need to operate as quickly.

 

I think i have the same problem.

I can hear a weird noise when im trying to boost at low rpms.

what turbo control actuator should i be looking at

the one on the exhaust manifold or the one on the primary turbo.

From looking at the turbo troubleshooting guide i can see 2 different ones.

How can i test to see if these are cuasing my problem?