293 replies to this topic

[Robbks]

connect the two GREEN diagnostic plugs together up under the dash and start the car.
let it idle.
it will cycle all the solenoids and should operate all the exhaust and intake valves so you can see if they're operating correctly

please please please forget about swapping turbo's.
just convert to single if you're going to do anything major.
FMIC kits are hard to come by for a TT anyway and you have to incorporate the ICV, etc into the piping.

TD05-18G @17psi
FMIC
TUNE
190ATW every day

reliable, simple and cheap.

[Tim.]

Convert to single ...Problem solved!

Yeah but single is shit.


Mbooma, another thing to test for vacuum leaks would be to connect only the green plugs under the dash and turn on the ignition but don't start the car. If the system holds sufficient vacuum, then it will operate the IACV and ECV a few times until it runs out of vacuum.

[Mbooma]

Tim can u explain a lil more im.trying to read up as much as i can but wat is an iacv an evc??

[Tim.]

These are the acronyms you'll see when reading up on the TT system.

IACV - Intake Air Control Valve
ECV - Exhaust Control Valve
SPRV - Supercharged Pressure Relief Valve
ABV - Air Bypass Valve (or blow-off valve)
MAP - Manifold Air Pressure (sensor)
MAF - Mass Air Flow (sensor)

Study this to learn how the whole thing operates:

http://www.veloce.pw...on/ttopprt2.htm

[Mbooma]

Ok thanks well i just bought some eletric solvent so ill start with my maf an.go from.there i.spose

[Robbks]

still don;t believe a total "no boost" is from a dodgy MAF on a TT

 

[TSG]

Sounds to me like something pretty major is getting stuck open for it to make zero boost, all the air must be escaping? For it to fix itself after an ecu reset, leads me to believe that thing might be electrical. One of the valves or solenoids would be my bet, but start small and work your way back toward the solenoid box, which thankfully hasn't given me trouble.

[U-Shell]

UK Legacy Forums have an excellent 'How To' guide on refurbishing the black box.

http://www.uklegacy....urself-cheaply/

Doesn't seem as scary as people lead on. It actually looks kinda of therapeutic lol.

[glenisanutter]

Yeah but single is shit.
 

SHIT MAY STINK BUT AIDS IS A TERMINAL DISEASE...lol

 

 

 

Hey Mboomba i stil have some left overs from the conversion  MAF boost control solenoid etc no black box but swap thing out one at a time so you can cross things off the list. And start simple first!      ps. there are some crucial hidden parts under the gaurds in a B4. vac tank etc.

 

You must start the engine briefly to create vacuum before checking for leaks. 

[WillC]

not to mention the Wastegate controller is in the passenger side guard as well : /

[MrSober88]

UK Legacy Forums have an excellent 'How To' guide on refurbishing the black box.

http://www.uklegacy....urself-cheaply/

Doesn't seem as scary as people lead on. It actually looks kinda of therapeutic lol.

 

That dude has some knarly nails.....

[Tim.]

UK Legacy Forums have an excellent 'How To' guide on refurbishing the black box.

http://www.uklegacy....urself-cheaply/

Doesn't seem as scary as people lead on. It actually looks kinda of therapeutic lol.

I've just picked up some 3.5mm hose to do exactly this. Interesting project and nothing much to it.

[Tim.]

Not hard at all Tim. You'll smash it and enjoy doing it! 
The hoses in my BBOD were in good condition but I replaced them anyway. The solenoids were chock full of gunk and it took several flushes to clear them out.

What hose did you end up using? Just some 4mm silicon?

Yeah my hoses are nice and compliant still. I'd just like to do it as preventative maintenance to keep those solenoids clean and clicking away happily.

[Mbooma]

Wow wat a lot of reading haha ok so after i reset the ecu the last time the car is making boost an i sprayed the maf anyway made no difference an the only thing wrong i can notice in in first gear (remembering its auto) the boost does do weird these it boost as normal then drops off the comes back ans then the other gears are taking a tiny bit longer to boost then normal so i really think it has some thing to do with blockages or the valves/solinoids are playing up so. ive decided im gonna change all the vaccuum lines today.... wat mm pipe are they?? and wen changing them do i just do to out side the black box or do i do a full make over an do inside aswell???

[Reevesy]

i can notice in in first gear (remembering its auto) the boost does do weird these it boost as normal then drops off the comes back

This would just be the VOD would it not? The changeover between primary and secondary Turbo.

[migoreng]

Wow.. no boost.. that would suck going up hills... lol

At least I still get 7 psi of boost when my engine goes into limp mode...instead of the usual 14 psi or 1 bar.

Ive only sprayed gunk out of the exhaust gas control solenoids. That didnt make muxh difference.

Will have to try cleaning the other solenoids but im not sure how to access the boost solenoid in the left guard. I can see 2 tubes running from the primary turbo around the washer tank.. I assume those go to the hidden solenoid and vacumm tank?

[Tim.]

I just find it hard to believe that it's a mechanical issue if boost returns after only an ECU reset.