MBC - fitting problems.

[Whizza]

Help guys.... I bought an MBC and an adjustable FCD.

I decided to fit the MBC first. So I found the Turbo to actuator hose and after some struggling managed to get it off. I measured the diameter of the hose and bought some longer length from Halfords. I inserted the MBC between the turbo and actuator and set it to it's lowest (counter clockwise screw).

Using my existing after market boost gauge (usually reads about 9psi on full boost - so should be accurate) I floor it and the boost hits 15 psi - and was still climbing . So I back off the throttle and drive home.

Can anyone explain why a.) I didnt hit fuel cut and b.) why the boost kept climbing.... I have double checked the connections and they look fine - no leaks.....

I then connected a foot pump to the hoses and checked for any leaks with the MBC in the closed postion and it seemed to be fine

Can anyone offer any advice please?

[psmiff]

Have you dismantled the MBC to make sure it is not stuck. Apparently this can happen. What sort of MBC is it. Did you disable the TVSV? What revision is your car.

[steve b]

sure you have the controller the right way round... i'm assuming its a grainger valve? You may need to cut a wind off the spring.

[Whizza]

thanks for the replies.

It is a Rev 1
I have not done anything with the vsv.
The ball is not stuck and when checked with a footpump - it seems to be fine.
The MBC has a small hole on the top if that helps

[psmiff]

You need to disable the VSV. Cut pipe and plug each end.

Your controller sounds like a bleed valve type, but that should not contribute to the high boost, I would have thought just the opposite but I have no experience of them.

You should have hit cut unless there is already a fuel cut defencer fitted.

[Whizza]

Thanks guys. It's definately a grainger valve... and fuel cut happened the morning before I installed the MBC..... so It's definately something I have done

To check the actuator - I have used a footpump and i can hear it click - so I'm guessing it's working???

[psmiff]

How about taking out the MBC, if thats all you have installed, and trying the car without it again. See what happens.

Wondering what you did to get to fuel cut before you fitted the Grainger valve!

[raptor95GTS]

You need to disable the VSV. Cut pipe and plug each end.

you don't need to disable the VSV on a rev 1/2 but rev3+ you do

[psmiff]

Mines disabled and everything is working fine! In fact, Grainger valve and FCD fitted by Rogue last week who disabled VSV as part of process.

[Cliff]

You need to disable the VSV. Cut pipe and plug each end.

you don't need to disable the VSV on a rev 1/2 but rev3+ you do

Are you sure? What's the difference as i have disabled mine and I have a revision 1?

[zero]

When i first fitted my MBC to my rev 1,
I didn't bother to disconect the VSV and got problems contolling the boost.

After disconecting it i had no problems also i cut 1 turn off the spring like steve b suggested.
Zero

[Steve Horrocks]

also found that i had to cut a coil off the spring in the grainger mbc if that helps at all, couldn't get below around 17psi otherwise.

[Whizza]

Ahhhh - you guys are so helpful .... I'm welling up here!

Thanks for the help - will try what you have suggested

[raptor95GTS]

You need to disable the VSV. Cut pipe and plug each end.

you don't need to disable the VSV on a rev 1/2 but rev3+ you do

Are you sure? What's the difference as i have disabled mine and I have a revision 1?

there was loads of debate on this topic on the old forum and the general knowledge was that on rev1/2 with the VSV being a simple on off switch is could left connected however most people disconnect it anyway

The rev3+ VSV is a constantly varying controller and thus needs to be disconnected.

Generally if you are having problems then the darned things get disconnected anyway so most folk don't even have this issue