so, heres what has happened.

i installed a hallman MBC last week, and put the heavy spring in it. I have it turned all the way down, and car runs fine. (but doesnt really ever get out of vacuum).
So i decide to start turning it up, back to near stock (until tune).

A few turns and a pull - boost gauge reads about 6, then a few more, 10, then again, 12, and the car ****ing feels like it hit a wall. Kindof like a rev-limit feel. Happened around 5500 RPM, and 0 counts of knock.

I turn it down a bit, and it happens around 10 PSI this time, and closer to 6500.

Each time the exact point the car bucks, the check engine light comes on, and PO234 is thrown - turbo/supercharger overboost.

any ideas? things to look at? or just save up my pennies until CBRD in a month or two?

 

sounds like boost cut. Its weird that it is stepping in at such low boost tho. what did you do with the factory boost control solenoid?

 

it could possibly be the gapping of your spark plugs because more boost can affect the spark

 

sounds like u have the mbc hooked up wrong or a line off causing the wastegate on the turbo not to open. This will cause a cut out like a fuel cut and it will very quickly throw a cel.

 

Ok, a quick before bed response.

i've got the boost source on the MBC coming off the turbo nipple. The other one is going to the wastegate. Stock solenoid is capped, as well as the nipple on the intake.

 

I have the same problem, but at high boost.. As if it wont hold up to it.. So i just turn it down a lil, but i would like to know why

 

yeah i also have that at high rpms in third gear. its deff over boosting. i believe your tuner can turn it off.

 

your boost gauge could be off, and the boost could be higher than you think

cb

 

Agreed you will find out when you go boom j/k

What type of boost gauge are you using?

 

You could be right, im using the ZT2 MAP sensor. I'm going to double check that line tomorrow for any leaks. But if i was off, shouldnt i get some knock?

 

I think, that maybe you are hitting fuel cut and you need a tune, pronto!

 

Well, figured out my problem.

I never altered the ZT-2 to read for a 5bar sensor instead of the default 3.5bar.

So that being said, what are some things i should check for signs of damage from the overboosting? happend a half-dozen times probably.

 

Im by no means a mechanic or tuner, however I think your car should be fine. That is why boost cut is programmed into the ECU so in the event that it overboosts itll save itself.

 

if the boost limit was set properly you shouldn't have any problems with the engine. just dial down the MBC to what it was before or better yet just get tuned at a higher boost.

 

Get a tune asap. Even if it's just a base flash it will remove that cutting and it will let u run more boost. Same thing happened to me when I first got my car and installed a MBC.