cant boost pass 7psi on a built motor!?!?!?!

[adrian2627]

I have a fully built 7 bolt with my fuel system upgraded, drivetrain, and ecu with dsmchips. Before we did the rebuild i was boosting at 12psi. Now i can only boost at 7 psi! I have a MBC and hooked up right still bossting at 7psi. When i take the wastegate hose off, it will continue to boost up to wherever. I did a boost leak test and the system will only pressurize to 5psi and i can hear air coming out of the tailpipe. i wanna crank the boost up to 16 can somebody help me? i know the actuator is working and all my couplers are good. TB seals have been replaced and so did the BISS oring. Like i said no leaks except for the one that goes out the tailpipe. thanks!

 

[phunny]

I believe that means you valves aren't closing. Chime in anyone?

 

[adrian2627]

new head job, valve seals, guides, pressure tested and pretty much completely redone head.

 

[iiiwildfireiii]

If you did a pressure test and are hearing air go though to the exhaust pipe...its valves dude. Make sure you've got it at TDC.

 

[adrian2627]

if its valves, how come ive got 180psi compression across the board? my turbo has minor side play. Im stumped coz i cant build boost pass 7psi coz of this. on a built motor with 3000$ invested and pushing only 7psi...you would be pissed too

 

[Chaddycakes21]

Check to see if your egr is stock open. I had similiar problems to yours. When i boost leaked tested my system all the air came out the exhaust and my tester read 0 psi. I ended up doing the egr block off mod. Do a search you'll find many results for it. Although controversial, i had great results doing this mod. I just used a piece of aluminum from a 12 oz pop can to block it off. You can use this link to route your vacuum hoses. http://www.dsmtuners.com/forums/showthread.php?t=198327 If you have good compression and the car runs good, i highly doubt that you need a head job .

P.S as noted first above before doing the egr block off mod try turning the crank over to TDC before you peform a boost leak test and see what you get.

 

[CanadianTSi]

When i take the wastegate hose off, it will continue to boost up to wherever.

Your Boost controller is either broken or installed wrong.

 

[Black91TSiAWD]

Your Boost controller is either broken or installed wrong.

I agree

 

[DarkStarMenace]

I agree, too. You just eliminated a component that affects your boost and the problem went away. And its cheaper to replace a boost controller than doing the head, again. If your MBC is good, you can test each cylinder for vavle sealing as long as you have access to an air compressor.

Adam

 

[adrian2627]

first of all thanks for the replies. I am going to change the MBC as soon as possible to rule that one out. I was just stumped that i have 180 psi on all cylinders and leaking air through the exhaust when i try to pressurize the system. I know i have no leaks whatsoever coz i did the soapy water test too and only gave me a leak in my greddy type s but that was fixed too. I might try doing that TDC static test maybe that will do something. Worst comes to worst, ill just hook the lines to the BCS till i get a MBC. Any other suggestions??

 

[ilikespeeding]

DSMTuners places a high value on grammar because saving the extra 2 seconds of typing means everyone spends an extra 20 minutes reading.

I dont know where you got a built motor for $300, but let me know.

 

[iiiwildfireiii]

Have you double checked your wastegate actuator to make sure its seating properly? Maybe it was misadjusted during the build? If its not seating, it might explain the pressure leaking out the exhaust.

 

[Zenja]

When doing the boost leak test, if your crankshaft is positioned at certain places, the intake and exhaust valves will both be open and all the air will go out the exhaust. If this happens, crank the car a bit and try again.