Stuck in VOD for 30sec +

[Rosssub]

Hi folks, I have a 2000 BH5 GTB rev b manual. If I change gear near VOD it stays in VOD for up to 45 seconds before boost comes back. When accelerating through VOD the boost drops off at 4000rpm as secondry kicks in but then the boost seems to rise as slow as the rev counter, it wont get to full secondary boost till about 6000-6500 revs. My primary boost is stable at 12 psi(0.8bar) at full throttle, once secondary reaches full boost it\'s stable at 16psi(1.2bar), it\'s just taking forever for the secondary boost to kick in.

Things I have tried/checked (thanks to the brilliant info on this site)

-Cleaned out BBOD

-Cleaned out primary duty solenoid

-Checked intercooler inlet air valve is working

-Checked exhaust control valve is working

-ECU shows no CEL\'s

-Pressurised vac system, no leaks

-Checked routing of all vac hoses

-Checked location of restrictor pills

-Checked condition of secondary turbo

All to no effect. I know that my older style HKS sequential BOV (not adjustable) has a slight leak under full boost and I have brought a factory bypass valve to replace it with just waiting for it to arrive. Are there any other possible causes that I should check out?

[Joker]

Sticky Exhaust valve?

[Marky]

Sounds like it, unwind the hex nut under the ecv valve and check the flapper can move freely right open and closed

sounds like its stuck half open, would explain the slooow spool up as well as the stuck in vod land

[Rosssub]

I\'ve checked the ECV, just double checked it. With actuator rod undone the flap moves very freely to fully open and fully closed. Have also checked the ECV actuator tank/diaphragm, positive pressure to top hose moves the rod and holds pressure and vacuum to bottom hose moves rod and holds vacuum.

[Joker]

vac lines aint melted or anything?

[Marky]

weeeeeird

where in the country are you? could be the ecu having a spazz somehow orrrr one of the solenoids to ecv getting stuck open or closed? the vac alone is enough to hold it open under boost, the positive port alone only part opens the valve

though that wouldnt explain it staying open once youve backed off

pass sorry, youve checked everything i can think of

is the car modified at all?

[Rosssub]

All vacuum lines cleaned, checked and double checked. I\'m in Greymouth, car is standard except for the blow off valve. I have an OBD cable and diagnostic programme which shows no faults. With the green diagnostic plug connected and ignition on everything is working fine. Also the rear section of the exhaust has been replaced and the cable is missing from behind the jack compartment, could this be anything to do with it? I hear the electric motor working when I turn the ignition on.

[telemekas]

Check SPRV (Supercharger Pressure Relief Valve) not sealing correctly

This needs to close which stops 2nd engine huff dumping to intake

Positive pressure via line No:8 closes it

[Joker]

as long as the butterfly is non existent in the pipe then no worries at the back end

[Rosssub]

Blowing through hose 8 into BBOD with the green diagnostic plug connected, airflow is bleeding out 2 of the solenoid air filters/breathers inside the BBOD and just switching from one to the other. Though airflow does become slightly restricted when the solenoid switches.

[Marky]

no no he means the bov itself - the secondary one - its the same part as the earlier bg/bd bov and they are known for failing at random. it would at least explain the super slow spool up if it was being forced open

block the hose - but after that plastic elbow bit - hose 22 still needs to plug in there

that valve works just like a normal bov, its held closed at all times apart from pre-spooling the secondary with the icv closed, if it stuck open you wouldnt know in primary only mode but once in twin itd just be like a normal bov leaking back to intake

[Rosssub]

Aw I was playing with the wrong end of the hose lol. Ok so Ive removed the secondary bypass valve, vacuum on hose 8 opens it/realease vacuum and it closes.

I have a vac gauge here, I can suck on the hose for the gauge and reach 17psi of vacuum, with the valve closed I cant get any air through it.

[Marky]

prob will be under boost though, not vacuum. just block the hose (somehow... duct tape over the bov inlet? haha) and go for a quick drive, youll know in a flash if thats your problem or not

[Rosssub]

I blocked the pipe between hose 22 and the relief valve with a 1/2-1/4 inch socket adapter, went for a drive and it made no change.

[telemekas]

SPRV faults can be difficult to assess

Best to test by swapping it out with a known working one

[Rosssub]

But it was completely blocked off, doesn\'t that rule it out?

[Eight_dollar]

driving it on primary turbo for 5min ( dont go past 3500 rpm or try to get on sec boost) - and there should be NO heat in the sec turbo

ANY heat indicates ECV isnt shut

(the rod will move as it should by the actuator, but the the valve (inside the exhaust) wont be seated

Also check primary waste gate plumbing and make sure the primary gate isnt sticky

Faulty or incorrectly plumbed Primary BOV can also cause low/no boost issues

[telemekas]

 Rosssub said:

But it was completely blocked off, doesn\'t that rule it out?

Rather novel way of doing it,but would rule it out.

[Rosssub]

 Eight dollar said:

driving it on primary turbo for 5min ( dont go past 3500 rpm or try to get on sec boost) - and there should be NO heat in the sec turbo

ANY heat indicates ECV isnt shut

(the rod will move as it should by the actuator, but the the valve (inside the exhaust) wont be seated

Also check primary waste gate plumbing and make sure the primary gate isnt sticky

Faulty or incorrectly plumbed Primary BOV can also cause low/no boost issues

If the ECV wasn\'t seated properly wouldn\'t I be having trouble with primary holding/building boost? The primary boost is very responsive and holds steady at 12 psi.

Primary waste gate plumbing is as it should be and restrictor pill is in the correct spot. I can hear the waste gate opening once secondary gets a bit of boost built up.

Primary BOV is plumbed correctly, is leaking slightly but I\'ve tried blocking the primary BOV off and still didn\'t help my VOD issues

[Eight_dollar]

so primary boost ok - ?

then look at the secondary change over items

IC intake control

EXH "flapper" ECV

If all this ok - then sounds like Sec turbo isnt huffing (

[Rosssub]

 Eight dollar said:

so primary boost ok - ?

then look at the secondary change over items

IC intake control

EXH "flapper" ECV

If all this ok - then sounds like Sec turbo isnt huffing (

 

Hi folks, I have a 2000 BH5 GTB rev b manual. If I change gear near VOD it stays in VOD for up to 45 seconds before boost comes back. When accelerating through VOD the boost drops off at 4000rpm as secondry kicks in but then the boost seems to rise as slow as the rev counter, it wont get to full secondary boost till about 6000-6500 revs. My primary boost is stable at 12 psi(0.8bar) at full throttle, once secondary reaches full boost it\'s stable at 16psi(1.2bar), it\'s just taking forever for the secondary boost to kick in.

Things I have tried/checked (thanks to the brilliant info on this site)

-Cleaned out BBOD

-Cleaned out primary duty solenoid

-Checked intercooler inlet air valve is working

-Checked exhaust control valve is working

-ECU shows no CEL\'s

-Pressurised vac system, no leaks

-Checked routing of all vac hoses

-Checked location of restrictor pills

-Checked condition of secondary turbo

All to no effect. I know that my older style HKS sequential BOV (not adjustable) has a slight leak under full boost and I have brought a factory bypass valve to replace it with just waiting for it to arrive. Are there any other possible causes that I should check out?

[Eight_dollar]

oh well you dont have a problem then !

Checked for silly things - like a rag in the inducer of the sec turbo or intake tube

or the bonnet sound deadening cloth layer sucked into air box?

[Eight_dollar]

how have you checked your sec turbo?

[Rosssub]

Airbox is clear with new filter, air inlet pipe and secondary inducer is clear and bonnet sound deadening cloth layer is intact. Secondary turbo fins are all intact and shaft spins freely. I\'m thinking maybe I have a faulty solenoid inside the BBOD that is not sealing properly, either the ECV positive pressure solenoid, ECV negative pressure solenoid or the ECV duty solenoid.

[Eight_dollar]

does the system hold vacuum? - a small hose runs off from the BBOD behind the airfilter box to the vac tank

The entire TT control system runs on Vac

Does the system operate properly when put into "D" check mode