Secondary Turbo inactive

[grunter]

Hey guys, experiencing what you might call over extended secondary turbo lag and would love to hear from anyone who's experienced a similar problem. State of play:
* no ECU fault codes,
* all vacume lines traced and replace where necessary,
* waste gate valves and soleniods check out OK although the solenoid did appear to be light on in the force required to open the gate, and
* turbo itself is producing sufficient pressure all be it ineffective.

[Robbks]

is the secondary actually producing boost? or is the primary just boosting harder (remember they both work in paralle over 4000rpm)

explain exactly what is going on

do you have two boost gauges plumbed in to know that the secondary is actually producing boost before the ICV opens up

this, read
http://www.veloce.pwp.blueyonder.co.uk/ ... opprt2.htm

[grunter]

Thanks mate appreciate the lead. Having read the info provided it could be one of several component faults. Essentially the secondary turbo isn't spooling up at all, it's cool to the touch after a good run which indicates the exhaust gas control valve isn't opening suggesting either split diaphram or positive pressure solenoid malfunction and/or ICV not opening as potential faults, for which there could be quite a number of gremlins in this overly complicated management system. As for my comment suggesting the secondary turbo is producing sufficient pressure I should've pointed out that was prior to noting the recent lack of secondary turbo boost, i.e. no second kick Armed with the valuable information you provided my odds of finding the probem have improved, a big thanking you. The other thing I should mention is that I had the intercooler out to clean the throttle body and the fault appeared soon after so maybe I should re trace my steps by disassembly, verification and validation of some key components.

If you have any further advice based on the afore additional info it would be greatly received as I wont get the chance to investigate before the weekend.

Thanks a plenty

[Robbks]

you removed the intercooler.
i suspect you have some incorrect vacuum lines going on

otehrwise first step is to open up the "black box of death" (BBoD)
and clean out every vac line and solenoid with upepr engine cleaner,
then clean all other vacuum lines

i suspect the ECV is not opening
it's actually pulled open by the lower, negative pressure port.
the positive port is less important, so much so that i bypassed all of the postitive pressure side on mine and it operated BETTER than ever before

to test it, hook up the necative pressure port to a manifold vacuum source with the engine idling, it should open. if not, diaphragm is stuffed

[grunter]

Hey Rob,

All's well, and ends well. Turned out all vac lines were fitted IAW the schematic and functional, would you believe the ICV butterfly was jammed closed, cleaned it up, sparayed a little INOX either side of the diaphram and flushed out all the associated vac lines whilst I was on the job. EGV doin the biz, allowing secondary spool up and +ve vacume at the ICV enabling supercharged air to make its way through the intercooler. Happy Days

My shout if I'm ever down your way. Thanks again for the material mate.

[Robbks]

no worries mate.

as complex as teh system is, it's usually a mechanical fault that causes issues
i.e solenoids or actuators being jammed with gunk

another tip for keeping the system healthy,
run a catch-can on the crank-case breather. it just helps to keep as much oil and gunk out of the system.

other tips, make sure you give the engine a good flogging every week.
i.e hot engine, and run it up on the secondary as much as you can.
this helps to simply get all that blow-by build up out of the secondary side of the system and keep everything lubed up nicely.
the hot air from teh secondary helps to vapourise the oil-sludge and push it through teh motor and burn it off. the old blowing out the cobwebs trick does have truth to it

[TSG]

other tips, make sure you give the engine a good flogging every week.
i.e hot engine, and run it up on the secondary as much as you can.
this helps to simply get all that blow-by build up out of the secondary side of the system and keep everything lubed up nicely.
the hot air from teh secondary helps to vapourise the oil-sludge and push it through teh motor and burn it off. the old blowing out the cobwebs trick does have truth to it

Very true, my car runs better after its been thrashed... its kinda kinky in a way.

I find the car just runs better when its being used for what it was built for, just gotta keep it safe and I only muck around on a quiet backroad here. Just getting it to 100 as quick as possible is usually enough, I find it fun to time it to see if its still working as advertised.