Boost Spiking Horribly on t25 turbo.... help!

[97GSTJake]

i have a t25 stock 2g turbo....Ok so i just recently had a new mbc put on my car (joe p) and my car was running great for quite a while.... and then all of a sudden when i got to get on it, i glance at my boost gauge and see that im running 25-30 psi... i know my boost gauge is correct because i can feel the amazing difference in sound and feel of all those pounds of boost compared to the 14 psi which I SET it at origanally. I have tried turning the mbc down, it softens so i know im turning it the right way and STILL it will noit turn my boost down. I can not go WOP on my car without get fuel cut and my engine feeling like its going to burst. Can someone please help me figure this out, im about ready to take the mbc back off and say screw turning my boost up any.....

 

[toecutter]

Do you mean that its was making 14psi for awhile and then jumped up to 25psi, or did it happen when you hooked up the mbc?

 

[Ultimatedsm]

I think you hooked up your MBC wrong, you have it reserved. WHen you reverse it, you build unlimited boost like what you are doing.

 

[ericbev]

DO NOT run your car like that untill you have figured out your problem. Not only will you burn up your T25 in no time but you could cause severe engine damage.

Define running great for a while.

I know its silly to ask but, did you check your lines to make sure it was installed correctly?

 

[97GSTJake]

the boost was at stock psi until i put the mbc on, then i turned it to 14 psi and it ran wop steadily at 14 psi, and then all of a sudden spiked to 25- 30 when i go wop, this happened like out of nowhere too.....

what do you mean i have it reversed? Like i am turning the mbc the wrong way everytime?

all lines have been checked, checked fine, have not ran a boost leak test for a while now but i know my bov flange is leaking just a tad at the moment.

 

[GVR4592]

How soon after you installed the mbc did the boost start spiking to 25 psi? Was it days, weeks, months? I would not drive the car until you get it figured out or uninstall the boost controller. You are going to cause serious damage to your engine and turbo.

 

[jaredgsx]

I think they mean you might have the lines hooked up backwards

 

[97GSTJake]

it was probably 3 weeks after i hooked it up that it started spiking really high....

 

[GSntncT]

not turning it the wrong way, but having the hoses attatched to the wrong fittings on the mbc. However, if the car ran at 14 psi for a while AFTER putting the mbc in, then I don't see how that is possible. Then only thing I can suggest is to check the hoses again. The smallest rip in them will send your psi level through the roof. Either that, or the wg is possibly stuck. How many miles on the turbo?

 

[97GSTJake]

haha, 122K miles

 

[GVR4592]

I would unhook the mbc and run the vacuum/boost source directly to the wastegate. If you get around 10 psi with it hooked up that way then the mbc is at fault. If it still spikes to 25 then make sure the line's aren't pinched, make sure the wastegate actuator isn't seized. Verify that the wastegate flapper can open.

 

[97GSTJake]

am i right though, this does not sound like a normal boost spiking does it?

 

[Jeff822]

The same thing is happening to me right now, it started after i got my old 3" downpipe on, i just put a new 2.5 inch turbo back on and it ran smooth for a couple days but nows its doing exactly whats happening to you, i try not to run over 10 psi, although my car is getting a E3b16g very shortly, someone also told me that my wasgate might not be opening like someone stated above so you might want to check that.