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Help, Not enough boost

989 Views 13 Replies 5 Participants Last post by  greenstreak
Here's my problem.
I installed a dejon intake today on my 1992 talon tsi, automatic. While installing the intake I found that I have a couple of vacume hoses that have no where to go. I didn't think it was that big of a deal so I installed the intake anyway. Well after I did that, I installed my hallmen manual boost controller. The problem I'm having is with the boost completely turned up, I'm only hitting about 9-10psi. What did I do wrong? Should the vacume hoses be connected to something? Thanks in advance for helping the newbie.
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1. Do not cross post. I saw this same topic in the Auto Trans forum. It is against the rules and will get yo banned if you do it over and over.

2. You should have no vac lines unconnected at all. If they are they are boost leaks and they will screw up your a/f ratio, overwork the turbo, and make boost unstable.

Where these lines disconnected on the car when you got it or did you disconnect them yourself?
I'm sorry about the double post. Won't happen again. The vacume lines were connected to the stock intake, but there is no connection for them on the dejon intake. That's why they have no place to go. Any ideas?
Are you talking about the breather lines that run into the intake (pipe from air sensor to turbo), or lines that are actually connected to a boost/vacuum source?
Your problem shouldn't be with the boost controller. THAT IS of course if you hooked it up right and tapped into the right hose. (The hose that runs from your intake manifold to your bov) and then ran the splice to the boost controler and then to your wastegate spring. The problem is with the hoses you disconnected. On your turbo there is a nipple that needs to be plugged up. If it is not plugged up then you will see major boost leakage Go to the local hard ware store and ask for black rubber nipples. And if they hand you a black nacked chick with breast implants then tell them "No the ones on the shelves." LOL
GODspeed1320 said:
Go to the local hard ware store and ask for black rubber nipples. And if they hand you a black nacked chick with breast implants then tell them "No the ones on the shelves." LOL
Man, they can keep the little rubber nubs, I'll take the naked chick! :D
LOL....I'm referring to the breather lines that go to the intake piping. I believe one comes off the valve cover and not to sure exactly where the other one comes from?
Well, they are going to be intake leaks letting in unmetered air since they are post MAS. This will actually cause a lean condition because it is sucking in unmetered air.

I would pressure test the intake system and fix any leaks you find. Hooking up the mbc wrong will only cause high boost usually not low boost. Atleast on a ball and spring design. If you take the mbc off the car can you blow through the valve with your mouth? All the way open you should be able too. You can overcome the spring pressure. As you tighten the valve you should eventually get to a point where you cant blow through it anymore. This is a good starting point for the setting of your boost level. If there is never a point at which it stops you from blowing through it there is a problem with the mbc itself.
The one that comes from the Valve cover won't cause a boost leak. It will however, if not rerouted or catch-canned cover your entire engine bay with a nasty thin film of oil. You can either route it back to the intake if there is a nipple for it, or, get yourself a catch can and hook it up to that.

The other one I don't remember right off the top of my head what it is, I tried to find a vacuum diagram online but no luck. I'll check when I go down to my car for lunch if someone hasn't answered you already.
The lines being open won't cause problems. One is to the charcoal canister (emmisions) and the other is the crankcase vent. My advice above was given before I remembered he had an intake pipe without the nipples on it. D'oh.
Thanks for all the info. Now that I know that those hoses shouldn't cause a problem, why is my car only boosting to 9-10 psi with the boost controller turned all the way up. I know on the automatics the turbo is smaller but I thought it would be capable of more then 9-10 psi. I will try to test the boost controller as stated above, but anyone have any other ideas?
Well, On every mod that I do to my car, I like to reset the ecu. It seems to run better. Just unhook the battery for an hour or more. The bad thing is if you have a stock radio you have to put in a secret code or you will not be able to use it.
Is there a generic stock radio code? If not, where do I find the code?
Resetting your ecu clears codes and starts you from a default blank slate. Resetting the ecu will do nothing for curing a boost problem.
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