weetbix13

at 7psi my wastegate is flapping in the wind... reaches 7psi quick then stays flat.
have checked the pills and gaskets and blow off valve hosing... all vacuum hoses have been done and are in the right place.

car is stock, so it could be a boost leak in the piping... who would be my usual suspects for the 7psi if it isn't anything in the title?

RotaryResurrection

iTrader: (8)

Wastegate solenoid stuck shut, unplugged, bad wiring to it...any of these will cause boost to stay at 7psi (wastegate spring pressure only) versus 10+psi (wastegate plus solenoid bleeding off pressure via duty cycle controlled by ecu).

Quickfini

iTrader: (6)

So what's your boost pattern? Is it 10-7-7?

My boost pattern used to be about a 10-5-5, and then I switched my precontrol and wastegate solenoids around and it boosted a 10-8-10. You may want to give that a check as well.

weetbix13

my boost pattern is a super reliable 7-7-7... hence what makes me beleive it is wastegate related. RR has made me think that it could well be up on those solenoids, hypothetically speaking (and i haven't checked them yet) what would happen if i had the plugs back to front on those? it seems like the most logical problem since the plugs are identical and side by side.

now, if all else fails, i could split those solenoids out of the system completely and put in manual boost control right? the Damien Diagram looks like thats a simple option.

adam c

iTrader: (2)

From the factory, one of those solenoids has a white dot on it. The plug that plugs into it also has a white dot. The white may wear off over time.

weetbix13

mmm, yeah, checked that and it looked fine.
solenoid also appears to work so i am thinking there is a loose connection to the wastegate actuator solenoid... nothing else would make sense to me at this stage.

any ideas on the best way to check that without a voltmeter?!

Quickfini

iTrader: (6)

See, this is what's weird with my car. I think they messed up the dots! Since when the dots were aligned, I had the 10-5-5 boost pattern, and when I switched it (so the dots were connected incorrectly), the boost pattern was perfect haha. I don't know what happened.

dgeesaman

iTrader: (7)

Ignore the dots - I've found they can be wrong or missing or whatever.

First, check the ECU for codes. If there is bad wiring or a dead solenoid coil, that will indicate it. But IME the ECU doesn't light the CEL when the solenoid codes are posted - you have to look for them. If you have a multimeter, check each solenoid for around 40Ohms of resistance when cold.

Second, try switching the electrical connections to the solenoids. The wiring for the precontrol (passenger side solenoid) has a Blue/Yellow and Black/White wires, and the wastegate has a Blue/White and Black/White wires, so the odds of being able to see the yellow vs. white stripe are small. Even if the wiring is correct, it's possible to get the vacuum hoses switched. IMO this is the easy/quick way to check for that.

Dave