over boost with MBC??

[LeeT5]

HELP!!

Was pm'd MBC instructions from Pedro and have followed them to the letter.
I have a Aux psi boost guage in a pillar pod and that works well too.... My problem is that since installing MBC the turbo spools up very quick (as you'd expect) but the boost guage rockets into 16+ psi territory and then overboost cuts in :slap:

The MBC is not even wound in one turn and already it is overboosting....has anyone else had this problem?

Can anyone help me as i really dont want to break my engine?

I only wanted to set it up to about 11psi but at the moment i really have to concentrate on guage- a bit frustrating to say the least.

[wright_t5]

Hi,

I too fitted an MBC to mine, it was nothing but problems from the minute I fitted it, fuel-cut all the time, had to back it off all the way, and yes the turbo spooled up quicker, but overall I don't think it was any better, and in fact it screwed the cruise, it was awful... kept surging rather than "cruising"... :slap:

My advice... go and see them guys at VT, spend some money and get it tuned properly... best thing I ever did.. :troutslap

[audimadmike]

I also followed Pedro's instructions and wow what a difference, initial fine tuning to stop overboost but now okay, although it did go over the other day when temp was -3C, but otherwise great.

I found this gadget has made more difference than any chip or tuning box fitted in the past and all for £30!

I have heard that some MBC's are not as good as others, mine came from a small garage that made them in Lincs.

mike

[siamblue]

As above mine has been fine from day one, think it depends on the make, mine is the boost sciences mk2,

for sale at £20 if anyones interested.

Gary

[audimadmike]

As above mine has been fine from day one, think it depends on the make, mine is the boost sciences mk2,

for sale at £20 if anyones interested.

Gary

In my view a BARGAIN! Give it a try..

Mike

[The Flying Banana]

As above mine has been fine from day one, think it depends on the make, mine is the boost sciences mk2,

for sale at £20 if anyones interested.

Gary


PM Sent for this.

[Ross9]

is it definately the MBC causing this, are you 100& sure its fitted correctly, sounds like the actuator is staying totally shut and not seeing any pressure at all, which is the way an MBC works, but it should open before 16+psi if it is wound right out. So either the spring is way too strong in the MBC, or there is a fitting issue or other unrelated problem.

Have you tried just running a pipe from the inlet to the actuator, ie no controller, when like this you should only get 4 or 5 psi IIRC on my Volvo actuator pressures, and would confirm it is the controller causing the bother.

Ross

[LeeT5]

:anmflower :B_steerin :remybussi

yipeeeee!!!!
Sorted...i found the screw was acting on the spring slightly and so i wound it out 2 turns and the boost dropped to 10psi, so i wound it up 1/2 turn and now boosting at 12 psi.

I am not going further.

Thx for all yer replys.

[JUDGENINJA]

Have you disconnected the BCS...?
It's the little box on the side of the air box..
Block off the pipe under the MAF and all you probelms should be solved..(in theory)

I used to hit 1bar (14PSI) and I'd get a cut out feeling....

[LeeT5]

Have you disconnected the BCS...?
It's the little box on the side of the air box..
Block off the pipe under the MAF and all you probelms should be solved..(in theory)

I used to hit 1bar (14PSI) and I'd get a cut out feeling....

:wtf: Bolox....thought i'd sussed it but it still keeps cutting out intermittantly at 11-12 psi...

In answer to your question no i havent disconnected the BCS, but there are no vacuum hoses connected....does that matter, and should there be any vacuum lines still connected to BCS?
and yes i have blocked off the MAF connection.

[JUDGENINJA]

disconnect all of them but leave the elctrical plug in...
Then block up the pipe coming out of the MAF and give the car a try....

Let me know if it works cos my cars on axle stands at the mo and I haven't retested mine after the above change...

[LeeT5]

disconnect all of them but leave the elctrical plug in...
Then block up the pipe coming out of the MAF and give the car a try....

Let me know if it works cos my cars on axle stands at the mo and I haven't retested mine after the above change...

Well the bcs was still connected (plug wise) and all the vac pipes are disconnected from bcs but it still occasionally 'cuts' but the boost does not peak above 12 psi. might turn mbc down quarter of turn to see if that stops the stalling....

[craig]

for abit of extra cash you can get loads more bhp from a rica 280 . i tried an mbc and it was fine one minute and cutting out the next if it was my car i wouldnt disconnect the pipes it overboosts for a reason. the surge of power down low in the revs is a sure fire way to bend something.

[elliot]

Try clearing the codes 414 has probably been hit.Also check for boost leaks the rubber elbow off the inlet manifold at the power steering pump end always splits due to heat!As mentioned make sure the vac line out of the middle of the BCS that goes to the inlet pipe is blocked so you you dont suck in unmetered air after the MAF into the inlet pipe.

[LeeT5]

Try clearing the codes 414 has probably been hit.Also check for boost leaks the rubber elbow off the inlet manifold at the power steering pump end always splits due to heat!As mentioned make sure the vac line out of the middle of the BCS that goes to the inlet pipe is blocked so you you dont suck in unmetered air after the MAF into the inlet pipe.

The vac elbow (the hard to reach one next to the manifold) was replaced last year cos it had split. The vac connection to the MAF meter hose is blocked. I turned the boost down 1/4 turn tonight, now gauged boost at 10.5 - 11psi but it still keeps cutting. Bloody anoying. I did disconnect battery for 10 minutes to reset ecu but alas no joy.

How can i clear the codes?

Anyone else have the same problem and fixed it?? :frown: starting to get frustrated with it mainly cos it only cuts now and again????

ps there are no air leaks.

[siamblue]

Lee mate what type have you fitted on the car? it isn't a Dawes is it?
My MBC has run now for 18 months with no problems at all, but my is a Boost Sciences and they are the best ones around that work on our T5's

Gary

[LeeT5]

Lee mate what type have you fitted on the car? it isn't a Dawes is it?
My MBC has run now for 18 months with no problems at all, but my is a Boost Sciences and they are the best ones around that work on our T5's

Gary

Got mine from a guy who calls himself 'gts chris'.
got it on ebay for £20, Brass type, spring and ball bearing..... heres the link:

http://cgi.ebay.co.uk/Manual-Boost-Controller-Nissan-Skyline-GTIR-200SX_W0QQitemZ8021600273QQcategoryZ32094QQtcZphot oQQrdZ1QQcmdZViewItem

Ignore the bit that says nissan skyline cos its the same boost controller for all models.

I'm just wondering if the spring is too strong in it??

[LeeT5]

:worthless

BTW how do i get piccys of my cool boost guage and pod for all yal to see!!??
at least that all works fine... :B_blite: