Help with Boost controller

[FSTRDNU]

i had my mbc hooked up for about 6 months fine, no problems. it adjusted correctly,
i recently installed my frontmount with intercooler piping, seemed fine, but i had the boost low, for safety. 10 psi. i turned it up to about 15 seemed fine. tightened some intercooler pipe couplings, and turned the screw outwords, counterclockwise, left. and the boost went up. could this be from a Huge boost leak i thought? probably. now i was at 20 psi on stock fuel, ouch. tighten a couple more screws, to assure for no boost leaks, and do the same small turn to the left, boost goes up agian. 20 psi at 4k, then i let off as always, casue it's breaking up. i loosen the mbc to the max 20 psi, i tried another mbc, same result, i disconnect actuator arm, 0 psi of course, now i thought maybe could i have been turning the mbc's the wrong way? so i put my other back on, put it 1/2 way, in the middle, 20 psi.
what is wrong?

 

[grpracing]

Check your actuator to see if it is still in tact. Pull it off and pull the arm outward, While it is pulled out put your finger over the vac port and then let go of the arm and see if it holds any pressure. If the blatter went bad the pressure applied to the actuator would just leak by and you would get no waste gate action. It sounds like the gate isnt opening at all.

 

[oldman]

Are you getting all out boost or boost creep? Bypass the mbc by connecting your pressure source directly to the actuator. Which mbc and how is it hooked up?

 

[FSTRDNU]

i punch it at 3k, and watch it quikly raise to 20, then i let off, i have another actuator, if i should try that

 

[grpracing]

Put the other actuator on and see if you get the same problem. But it is still a good idea to make sure you havent miss route the mbc lines some how so make sure you check them when you change the actuator.

 

[oldman]

Bypass the mbc by connecting your pressure source directly to the actuator.

Do a test run, this is to determine if your actuator is defective.

Which mbc and how is it hooked up?

I'm not doubting your abilities but it's always good to double check.

 

[FSTRDNU]

im sure it was hooked up right, it worked good for months, ill try to do the test tomarro.

thanks oldman

 

[FSTRDNU]

double post oops

 

[FSTRDNU]

triple post opps

 

[oldman]

If you get a steady boost of 10-12psi when you connect the pressure source directly to the actuator, either you have a defective mbc or it's not hooked up correctly. If you're still getting all out boost, either the hose to the actuator is trashed or you have a defective actuator that doesn't open. Post back results.

 

[FSTRDNU]

wierd.
i investigated, and my actuator was loose, it wasnt bolten down tight. tghted it, same 20 psi.
run no MBC, run hose straight to actuator, 20 psi, switch for a differant actuator, bam 10 psi.
i just cant see how the actuator was bad?
do they fail?

 

[grpracing]

I had the same problem and when I checked it out the actuator had broken loose from the bracket. I had just been in there 2 days before and it was in tact. Glad you found the problem. And yes they do fail either the welds will break or the bladder inside fails or they rust out. Good luck with it.