Uncontrolled boost problems

Car is an '04 SRT4 with an unknown past, trying to get it back in shape. Stock turbo with I think a stage 2 adjustable wga, also has hard pipe intake and catless exhaust.

Current issue is no boost control. With wga hooked up just to the turbo outlet it will boost to 8 or so psi, so it works correctly. With the wga hooked up to factory boost solenoid so the computer will control it, boost will go well over 20 until you back off(which we do). Should be able to boost to a spike of 18-20 and hold around 14-16 psi. I tried using an Diablo Intune tuner to lower the boost but it didn't change. I have checked and re checked the vac lines. I replaced the all hard pressure sense lines with new rubber lines. The only boost leak I can find is leaking through the blow off plate the PO installed. The solenoid works as its suppose to.

Please help. This car belongs to SWMBO and she is not to happy.....

What is a wga?

Wastegate actuator.

Sounds like the problem belongs to the "computer". Any way to troubleshoot? Factory electronics not playing well with the aftermarket parts? Wiring intact and correct?

All wiring looks to be good. Computer is not throwing any codes, and car runs well. The wga appears to be the mopar aftermarket piece. The computer is currently running the factory tuning, and has been reset.

OK, with car turned to the run but not started the solenoid is getting voltage. I used my boost leak tester and pressurized up to 20psi and there was no voltage change to the solenoid. Should there be? Or does the car have to be running? If so how could verify the solenoid is functioning when the car is running?

WASTE GATE ACTUATOR

remove "performance part" replace with stock.

I don't remember exactly how they decide to fire the solenoid on the srt, but I'd make sure you're getting a good MAP signal to the ECU. Throw a scanner on the obd port and watch the vac/boost level as you apply psi through your boost leak tester.

Maybe the leak on the surge valve block off is causing a problem? Isn't the reference feed for the wga solenoid fed directly off over if the nipples on the turbo? How much of a leak are we talking about?

Sounds like the solonoid has failed in the closed position. That or the computer is not sending contol signals, but that is less likely unless the MAP sensor has failed. Make sure the lines to the solonoid are routed correctly too.

In reply to wae:

MAP sensor is in the center of the intake manifold plenum.

OP- I have an SRT4 MAP sensor if that's the issue. Yours for shipping.

Fueled by Caffeine wrote: remove "performance part" replace with stock.

I don't have the stock WGA, but as I said it works correctly. The only thing I can think is the computer is not controlling the solenoid, but I don't know how to check that while it is running.

With my tuner I checked the MAP and TIP pressure sensors. Both read the same, at 0psi they read 91kpa and at 10psi both were 160kpa(I'm at 2,700 ft).

If the sensors are reading properly then either the computer is failing to tell the solenoid to open it the solenoid had failed.

I don't know the diablo system, but assuming that it isn't doing anything to try to control the boost to a higher psi, it sounds like the solenoid might be faulty. Is there some way to reset to factory defaults with that system?

You should be able to test the solenoid by applying power to it and listening for the click. It's an on/off affair. You can use a mity-vac or just go all megamaid on it (suck and blow) to make sure that its diaphragm isn't leaking. Without power the top two ports should be connected and with power the bottom two should be connected.

So I swapped the boost and TIP solenoids, wiggled all the vac lines, yelled at it a couple times and on the test drive it did what it should. Boosts up to about 18 then slowly drops. Not sure which fix fixed it, but it works now