355 F355 subdued after Tubi manifold upgrades

warm the car up, stick on a suitable glove then have someone rev the car whilst you hold the valve open. Then you'll be able to hear the sound known the valve is open. Then do the same, have someone rev the car while you watch the valve and see if it's opening.

Go from there.

 

Did a "rev test" today and the valve rod doesn't move. Sent all the info back to the garage to see what they think.

 

You can remove the hose from the bypass valve solenoid. Open valve by hand, finger on hose, making sure that hose holds vacuum.

Check that the vacuum canister itself is storing vacuum.

Make sure the electrical plugs for the bypass solenoid and air injection solenoid are not swapped.

 

If it's gone wrong, it was the garage's doing. I'm happy for them to do the work to correct their mistake

 

Just telling you things that would take less time than even driving the car back to them but whatever you prefer.

 

Every time I've suspected my valve wasn't opening, it wasn't. Usually just a small thing and easily fixed - like a crack in the vacuum hose to the diaphragm.

"If there is any doubt, there is no doubt."

 

Sounds like to me there's something wrong with the way they put it back together.

The difference between factory headers and Tubi headers is not THAT discernible. I would wager your valve isn't opening.

 

on a 5.2 car aren't you suppose to get a CEL or something if the valve isn't opening?

 

Apologies, didn't mean to come across as dismissive. Just recognising my own technical limitations!

 

I think I might have found the problem. I think one of the solenoids must be for the valve. The pipe that connects to the bottom of the blue T is flared and split where it connects. Going to try some tape to see if that helps.

Can someone explain why there are 2 solenoids and what the weird blue t-junction is doing please?
Image Unavailable, Please Login

 

All good no worries. Tape? Nevermind, drive it back to them

The "T" is connecting both the bypass solenoid and the air injection solenoid to the vacuum canister. (vacuum source for solenoids)

The top port on the solenoid closest to the cat ecu connects to the small hard line on the air injection tubes which then connects to the vacuum hose to the bypass valve.

Any hose that is cracked cut back to where it isn't and put it back on (or replace if brittle). The "T" doesn't look original and may be slightly too big causing the hoses to split.

 

Yeah, I think the hose might have been cut in order to get it to fit. Not sure I can push it back on now that it's been cut flat.
Image Unavailable, Please Login

 

Bit more of an update...

If I manually lift the valve rod it definitely engages the nice sounds.

I couldn't get the rubber tube back over the nylon t-junction, so I made rubber sleeve from an old washing machine pipe (see attached photo). Unfortunately, that hasn't fixed it, but my next step is to tighten the hose clips to see if it's just not making a vacuum.
Image Unavailable, Please Login

 

That's probably as bad as trying to use tape.

 

Oh . Padded the "inner" tubes with some tape. It's a pretty nice snug fit even before the hose clips were tightened.

 

It's your car to do what you like with of course but a hose inside a hose with tape and clamps is a literal dumpster fire.

Pretty easy to fix it correctly so you won't have to worry about it again.

 

Trouble is, I'm not sure what the correct fix is, without replacing the whole pipe for a wider one, or finding a narrower t-junction. I've looked on Amazon but can only find replacements for the one already on their.

 

121793 Ferrari

 

Ah, nice. Looking at it, though, it says it's a 4mm junction. Pretty sure the one that's currently on there is also 4mm. Would the hose be more pliable if I dipped the end in hot water for a bit?

 

Yeah I don't know because when I have a hose that's so brittle it's splitting I just replace it.

 

Any 4mm vacuum hose will do. The O/D of that blue fitting looks quite large however.
Regardless, it seems like a vacuum leak maybe your initial culprit.
https://www.ebay.co.uk/itm/364222442994?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338590836&toolid=10044&loc_physical_ms=41774&customid=00ddb428eb021d8aa2ccdca9d2545d32&gclid=00ddb428eb021d8aa2ccdca9d2545d32

 

Success! The t-junction was too big (6mm). Swapped in a 4mm that arrived today and sonic goodness has been restored!

When it's cold I'll re-trim the hose past the new deliberate split that I added.

Last question... is it possible for the valve to partially open if there's not 100% vacuum, or is it "all our nothing".

Thanks to everyone for their help
Image Unavailable, Please Login

 

Vacuum (by nature) will be all or nothing.
That said, worth checking the operation of the valve itself (both for rattles and smooth opening).

 

At 10 psi, the valve fully opens. Anything from 0-10 psi results in partial opening.