MAJOR boost spike!

[domenico_169]

k well for like 2 weeks now i have had a major boost leak problem! my boost would go up to 15 then drop to about 10-12. and now today all of a sudden, might i mention after doing absolutely NOTHING! i have major boost spike, like way over 20 lbs. i have a turboxs dual stage boost controller and my boost spikes only at real high rpm, i dont understand. oh and i also noticed when i puuled over to put my boost all the way down , my o2 housing was BRIGHT red, and so was my exhaust manifold a little, i am guessing this is from the high boost and it is kinda normal right? but what i am really concerned about it the major spike, what can i do.

 

[AwdEi]

You may need to port the crap out of your wastegate and o2 housing (if you haven't already). I have my whole set up ported, it will creep every once and a while. I guess I could have gone farther and will soon.

If you have a stock exhaust and try to run more boost, it will raise you engine temps. I am not sure how much, but I know it is higher than stock.

Hope this helps.

 

[domenico_169]

my o2 housing and exhaust mani are ported, and i dont think that the wastegate is, but i dont understand why this would happen. when i first did all my mods it run PERFECT! then a few months later i started to have boost leaks, and now all of a sudden i have boost spike! and between all of this i have done NOTHING! someone please help.

 

[Dieselboy]

Check your turbo for shaft play and check your manifold for cracks. I had the same problems and when I did my 16G install, I found my 14B was toasted and my mani cracked to hell.

 

[domenico_169]

k but heres the thing too, if i have my boost set at like anywhere between anywhere 10-13 it wont happen.

 

[Dieselboy]

Same thing with my situation. Stock was fine,anything higher dipped down.

 

[REDBLUR]

Probably have a leak in a vac line to the waste gate actuator. I just had the same problem. Small pin hole leak in my vac hose would expand under boost and leak all air out, thus not opening the waste gate.

A good way to check for leaks, and to see if the actuator is working:

Get an air needle (used to fill basket/ volley balls) that attacthes to a regular bike pump.
Take some tape and wrap it around the needle so it makes an air tight fit when you jam the vac line on it. Don't put tape around the little holes at the end of the needle!
Now disconnect the lines at your MBC. Pressurize the line to the waste gate actuator (should open at ~10psi) and check for leaks. Pressurize the other line for your MBC (if its t'd to the blow off valve vac line, take a pair of vise grips and pinch the line going to the intake air tight, you can't pressurize the entire intake with the bike pump) and check for leaks. You could also check the MBC itself to see if it leaks. Some may bleed a tiny bit of pressure via a very very small hole.

If all else fails, by pass your MBC and run a line directly to your waste gate actuator from the t'd blow off valve line or turbo nipple. This should set your boost around 10 psi.

 

[domenico_169]

i will try what you mentioned, but the thing is i have the boost controller turned all the way down right now and it sits about about 12-13 lbs and when its set to this i get no spike at all, but its once i set it a little higher than that. i wish i just had a winter beater so i can work on my car all winter and get it going the way i want, or at the least be able to park it for a month.

 

[domenico_169]

hey i just noticed something messed up that wasnt like this before, one of my metal vaccum lines tahts for my cruise control is busted, i must have broke the stupid thing when i had to replace my lower heater hose a week ago, anywaym could this vacuum line be causing the boost spike? if so, can i just cap it off or something to prevent the problem, cause the line cant be replaced cause its metal and where it connects is metal so im ####ed and i would have to replace the whole unit which is like 200 bucks and considering i dont ever use cruise i can care less.

 

[domenico_169]

k well i fixed that line and it did nothing for me and i also turned my boost down as low as possible but yet it just goes up like crazy, once and while it will drop again, but most of the time its just keeps rising till i hit fuel cut. im soo damn mad.