Installed BOV and MBC- Now Lagging.

[KKneipper]

I installed my new BOV and manual boost controller a few days ago... it worked fine til this morning, keeping me at a steady 11 psi. now when i give it some gas it sounds like it's getting power, but my tach, boost guage, and spedometer are just barely creeping. this continues until i get into 3rd gear (automatic), then i start getting what i'm thinking is fuel cut. all of a sudden the car will start "bucking" like it's pissed off.

so i turned the boost back down and made sure the tension screw on the BOV was tight. no luck. i don't know what the hell is going wrong, seeing as it has worked fine for the last few days.

 

[cra]

sounds like a significant boost leak(s) need to be located and corrected. keep us posted.

 

[KKneipper]

i just did a boost leak test... my throttle body shaft seals are leaking a bit, but they were doing that when i did my last test about 3 months ago. other than that i'm not finding any leaks.

let me elaborate a little bit. the "bucking" is more of a sputtering, i had adjusted my biz screw on the throttle body about 1/4 turn, didn't work, so i adjusted it back to the exact same spot its has always been, and it's still sputtering.

took the new boost controller off and reinstalled the OEM one. still sputtering.

even sitting still at an idle, the tach reads 500, then drops to 200, then back to 500, and keeps bouncing back and forth.

any help?

also, when i first adjusted my boost this morning, i got it to spike to 19 psi, then it would settle at around 16. i only drove it for 2 blocks and that's when my problem started. it started with the fuel cut, so i turned around and got it home... i hope i didn't #### anything up with that 19 psi spike, but i only boosted it for 2 blocks, so i wouldn't think anything could have happened to the engine...???

 

[Luckybob2485]

It is possible that something could have happened with that 19 psi spike. Is the blow off valve possibly stuck open?

 

[viprez586]

If you bought an aftermarket BOV that vents to the atmosphere that's your problem. Recirculate the BOV - if you have that much of a desire to hear the damn thing all the time upgrade your intake and intercooler piping.

What your describing is a boost leak and your symptoms are known as idle surge.

Hitting fuel cut saves you from blowing stuff up, you'll be okay. Just research on modifications before you perform them so you know what to do and how it install it. Fix all your boost leaks as any little leak will make our cars run like ass. Get the standard NGK copper plugs and gap them to .028"

Here is my definitive MBC hook-up. You need one single untouched vacuum line to the BOV - to re cap...DONT tap into this vacuum line for anything else!
<img src="http://www.dsmtuners.com/gallery/files/7/2/2/1/8/simple.bmp" alt="Mbc For Idiots" />

It is possible that something could have happened with that 19 psi spike. Is the blow off valve possibly stuck open?

Possible? Yes. Likely No.

 

[KKneipper]

i just took my BOV off, and put the stock one back on. did the same thing with the boost controller. still had the idle surge. then after about 30 seconds of idle my CEL came on... i'm too scared to drive it to checker or autozone to get the code pulled for it... i'm getting really mad at myself. this car had run great up until i put these parts on it. no problems what so ever. now i am thinking that i may have screwed something up.

the MBC i bought, i have found through research, had labeled the arrows wrong and i may have hooked it up backwards. could that mess up my wastegate eventhough i had just driven about 2 blocks with it like that? and if so, could that be the reason for my CEL?

Here is my definitive MBC hook-up. You need one single untouched vacuum line to the BOV - to re cap...DONT tap into this vacuum line for anything else!
<img src="http://www.dsmtuners.com/gallery/files/7/2/2/1/8/simple.bmp" alt="Mbc For Idiots" />

thanks for the diagram. that is how everything was hooked up, and i'm thinking that the MBC being possibly labeled wrong may have caused me to hook it up backwards.

 

[cra]

you did not indicate what type of BOV you installed and if your are using the stock or upgraded MAS/MAF?

do you have a data logger? what code did it throw when the CEL went on? did you reset the ecu before continuing to diagnose the problem?

double check your vacuum lines to the MBC and throughout. also be sure none of your hose clamps is stripped or has snapped.

if the problem persists also check to be sure one of the legs of your TPS has not gone bad (take it out and check with an ohm meter). good luck.

 

[redrockergsx]

with the up and down throttle check the throttle screw and turn it not to much till the up and down throttle is fixed. with the boost make sure you have all the vacuum line hooked up right and check the waste gate and see if the line is still there cause if the line came off the you will only run the minimum which what ever it is most likely 7 to 12 psi

 

[KKneipper]

you did not indicate what type of BOV you installed and if your are using the stock or upgraded MAS/MAF?

do you have a data logger? what code did it throw when the CEL went on? did you reset the ecu before continuing to diagnose the problem?

double check your vacuum lines to the MBC and throughout. also be sure none of your hose clamps is stripped or has snapped.

if the problem persists also check to be sure one of the legs of your TPS has not gone bad (take it out and check with an ohm meter). good luck.

i bought an ebay knock off of the turboxs rfl type h. it was cheap and thought i'd give it a shot. i also bought the ebay knock off of the turbo smart boost controller. i have read in another forum (after i got the damn thing) that the knockoff company mislabeled the arrows pointing to the wastegate... so i may have hooked it up backwards... could that cause any major damage with only about 2 miles total driving with it like that?

also, i'm using the stock MAS. i'm basically stock except for a k&n cannon filter, aluminum intake pipe, and a glowshift boost gauge.

unfortunately i do not have a data logger, and didn't have time to make it to the shop to get the codes pulled before i had to go to work (took the wife's car). to tell the truth, i'm too damn scared to try to drive it down there and back.

and i don't know how to reset the ECU... this is my first dsm, and for the 6 months i've had it, i haven't had any problems.

and i've taken everything apart and put it back together today so many times that i can't even count... probably 7... i've triple checked every clamp and vacuum line.

-----------------------------------------------------------------------

i really do appreciate everyone's advice so far, and i'm sure that someone here has had the same problem and everyone has found a different source. i'm tired and stressed, so i'm going to bed for the night and i'll get back on it first thing in the morning....

thank you all!

with the up and down throttle check the throttle screw and turn it not to much till the up and down throttle is fixed. with the boost make sure you have all the vacuum line hooked up right and check the waste gate and see if the line is still there cause if the line came off the you will only run the minimum which what ever it is most likely 7 to 12 psi

i've messed with the BISS screw off and on all day, making tiny adjustments, and it'll help for about 2 seconds, then starts surging again.

 

[cra]

to reset the ecu, just disconnect the batery, wait a few minutes, then reconnect. you may be pleasantly surprised.

connecting the mbc lined backwards should be fixed, but it appears you are getting some boost. a faulty or incorrectly installed mbc usually results in running lower than desired boost (annoying but you should be able to drive it). i would not worry too much about the sudden and one time spike to 19 lbs of boost. until you get this fixed, just turn down the boost when driving it.

i am not sure the folks at autozone are knowledgable enough about your car to help you. find someone from the local scene who has a datalogger and can help you.

 

[KKneipper]

to reset the ecu, just disconnect the batery, wait a few minutes, then reconnect. you may be pleasantly surprised.

i am not sure the folks at autozone are knowledgable enough about your car to help you. find someone from the local scene who has a datalogger and can help you.

right on, i am on my way out to the drive way, to try all this one more time. only reason i was going to take it to autozone, was to have the code pulled for my CEL.
i'm just hoping i can get this taken care of quickly and cheaply... because my wife is not too happy with me... or the talon. haha.

 

[cra]

it is always a good idea to manage perceptions with upper management ;-)

 

[CRANKED91TSI]

to check for a boost leak you can make your own boost leak tester. Go to the hardware store and get a 2" or 2 1/4" PVC end cap, and grab a valve stem while your there. drill a hole in the end of the cap thats just barely big enough for the valve stem to fit through (if too big the valve stem will blow out, and it proves a little painful, i speak from experience ) then get a 2.5" intake coupler and attach it to the intake side of your turbo, hook an air compressor up to it, have a friend watch your boost gauge (hopefully you have an aftermarket one) pump the system up to about 15-17 PSI and listen for leaks, ive been told to spray Brake parts cleaner on your TB and piping or wherever you might think there is a leak but i dont really want to spray BP Cleaner all over my stuff. so i just listen,
Hope this helps
-Twitch.

 

[KKneipper]

to check for a boost leak you can make your own boost leak tester. Go to the hardware store and get a 2" or 2 1/4" PVC end cap, and grab a valve stem while your there. drill a hole in the end of the cap thats just barely big enough for the valve stem to fit through (if too big the valve stem will blow out, and it proves a little painful, i speak from experience ) then get a 2.5" intake coupler and attach it to the intake side of your turbo, hook an air compressor up to it, have a friend watch your boost gauge (hopefully you have an aftermarket one) pump the system up to about 15-17 PSI and listen for leaks, ive been told to spray Brake parts cleaner on your TB and piping or wherever you might think there is a leak but i dont really want to spray BP Cleaner all over my stuff. so i just listen,
Hope this helps
-Twitch.

i already stated that i have done a boost leak test, and aside from a tiny leak on the throttle body shaft seals, everything was tight.

took the car to autozone, had them pull the code from the CEL, and cylinder 1 was misfiring. i pulled the plugs, re gapped to .028, and then swapped them. drove around until the CEL came back on, and took it back to have the code pulled again. still cylinder 1... so i replaced the wires and everything is working great!!!!!!!!!!!

no more idle surge, no more fuel cut, and it was all due to adding extra power that the wires couldn't hang with, and one shorted out. but now i'm doing good, and the car is running like a champ again!

GO DSM!!!!!!

thanks for everyone's help and input. it was greatly appreciated.

 

[redrockergsx]

that good that a cel came on cause sometimes they dont good job man hope you have fun with it now

 

[cra]

nice. this should also make the rest of the household happy ;-)

 

[KKneipper]

nice. this should also make the rest of the household happy ;-)

haha. that's great man. the household is now peaceful. most of it was me being pissed and acting like an asshole... you know how it goes. haha.

still having an issue with my boost controller though. i can't seem to get past 11 psi. and the only time i got it up as high as that 19 psi spike, it was set up using the t fitting that came with it. but it didn't make sense to me to have the exhaust port on the boost controller just venting under the hood... is that how it's suppost to be?

right now i just have the line from the turbo going to the boost controller, and the wastegate line connected on the other port (and no, its not hooked up backwards). the line that goes to the boost control solenoid, i just plugged with a screw to keep the CEL off. no matter how much i adjust it, and the throttle body biss screw, it won't get up any higher... i'm only hoping for 14-15 psi.

 

[cra]

here is a site with links to download MBC install instructions with great diagrams. here are other info that I hope are useful for you (pardon the wordiness or possible repetitions of things already noted above)...

on your stock MAS with an aluminum intake pipe set up:
1) does the intake pipe have a nipple that is sticking out where one of the stock hoses from wastegate solenoid (WS; located under the MAS and air filter box) would go? if not, then you are OK.
2) if so and this hose is connected, then disconnect the hose from the intake pipe nipple (plug up the intake pipe nipple). see below for what to do with this hose, the other end of which should still be attached to the WS. [note: some people refer to the wastegate solenoid as the boost control solenoid (BCS).]
3) leave the above noted hose connected to the WS/BCS. remove the other hose connected to the WS/BCS and plug it up or the nipple to which it is connected on the other end (DID YOU DO THIS? IF NOT THIS COULD BE THE SOURCE OF YOUR PROBLEM). take the end of the hose that you disconnected from the intake pipe nipple and attach it to the nipple on the WS/BCS from which your just removed the other hose. you essentially created a closed vacuum loop on the WS/BCS. it appears that you elected to leave the hoses on but plugged them up. this is fine too. however, you do have to plug up the other end to which the other hose (not the one that was on the intake pipe nipple) connects. you already know that for 2G cars the WS/BCS needs to be plugged in electrically to avoid a CEL.
4) zip tie the hose connections from bov to the head. do the same for the ones from the mbc to the wastegate and turbo or J pipe. this ensures tight, leak proof connections.

other related things to check:
a) just want to be sure that the line connecting turbo to mbc is at the location of the turbo j-pipe (extension of the compressor) or compressor housing outlet, and not anywhere else. as noted by viprez586, the mbc pressure source line should not be tapped ("T'd") to another existing vacuum line like the one from bov to the head. nor should another line be tapped to the lines connected to the mbc.
b) also curious how long are your hoses? they should be as short as possible for best boost response.
when driving start by setting the mbc as low as it can goand incrementally increase boost from there.
c) if you have not yet done so, check that your wastegate is working properly?
d) if the problem persists, borrow or make a boost leak tester to be sure that it is holding pressure significantly greater than the 11-12 lbs you are getting now.

hey, from this post, I just noticed my proven member status. cool!

 

[KKneipper]

the boost control solenoid (located below the fuse box) has two lines coming from it. one of which goes to the t fitting between the line coming out of the turbo j-pipe and the wastegate. i replaced the t fitting with the mbc, and plugged the line that goes to the boost control solenoid. the other line coming from the boost control solenoid attaches to the intake pipe between the mas and the turbo. that is still hooked up. should i disconnect that one and plug it?

also, the hose from the turbo j pipe to the mbc is about 4 inches long, and the hose from the wastegate is only about 2 inches long. i'm pretty sure this is short enough. i don't think i can make the hoses any smaller and still be able to reach the mbc without taking the intake off.

 

[wishnfor4g63T]

how to fix MBC,

I have a pretty good feeling i know which mbc you have without pictures. Theres a knob at the top and 2 fittings at the bottem for the vacume and wastegate.

i pretty much realized after my first pass with i hit target boost. (stock turbo t-25) @ 16 psi. Next step of the gas i was down to 12. ehhhh??

So i pull off re adjust it again. 17 psi then back down to 12 in a matter of seconds? why? take it back home and figure out why they put an allen wrench in there. The little allen in the bottom of the mbc needs to be tightened down EVERY TIME you turn it. man it's a pain!

Next time have a fellow dsm'er either sell you a home made MBC ball and spring or buy a joe p.

but goodluck man glad it wasn't nothing serious on your car!

 

[viprez586]

So i pull off re adjust it again. 17 psi then back down to 12 in a matter of seconds? why?

Boost leaks also cause this. Fix those TB seals!
Might as well get some phenolic TB spacers too.

Food for thought here: I did the Phenolic TB and Intake manifold gaskets, along with my FIAV coolant line delete. I have no hard data but most users would agree after a short(or long) trip of boosting hard, you'd get out and admire your engine, set you hand on the intake manifold and nearly burn your hand off(or use it as a hand warmer in some cases).
Now with the spacers my intake manifold maintains same if not slightly warmer temperature then my FMIC.

 

[cra]

...the other line coming from the boost control solenoid attaches to the intake pipe between the mas and the turbo. that is still hooked up. should i disconnect that one and plug it? ...

Yes, disconnect it from the intake pipe and plug/cap the nipple. You can plug it up or connect it to the other nipple on the WS/BCS after removing the other line (that is plugged up and still connected to the WS/BCS).

 

[KKneipper]

i didn't figure that would matter, since there's not really any pressure on that line. it's not leaking, so i might as well leave it where its at. my main question was about the t fitting that came with my boost controller. as far as i'm aware, the t fitting has a ball and spring in it, which would mean that i would have to use it to get the boost controller to work right. i just don't know about venting the 2nd port on the mbc to atmosphere.

and i know, it makes about as much sense as venting the BOV. however, i'm not looking to get a 9 second car, and the vented BOV was cheaper. the stock 2g BOV leakes pressure around 10 psi, and most people know that. so i was just looking for something that was cheap and would hold more boost.

 

[cra]

to put it to real test, try to borrow a friend's MBC (the simpler types like the joep or equivalent and install it. if the problem goes away then there is an issue with your mbc. if the problem remains, then at least you know it is not your mbc.

 

[KKneipper]

I have got my MBC hooked up right and I can hold a steady 16 psi at half throttle. I decided to really get on in the other night and blew the coupler off the upper intercooler pipe where I had to cut it to fit the new BOV on. Other than that though, the car seems to be much happier now. But it doesn't like the 30 mph speed limits through town. It always sounds so disappointed when I have to let off the gas. The BOV just kind of flutters and sounds so sad.... Hahaha... But if I let it really spool and hold at 16 for a second.... it's loud. Super loud. So I'm content for now.