My Emira has a screw loose (boost bypass valve)

[RPM]

The stop screw for the throttle bypass actuator arm must have backed out yeeted itself out of the engine bay. I did not see it, nor did my magnet grab it when I dragged it around the valve cover.

Without the stop screw the butterfly valve slammed shut hard enough to jam closed, and stop actuating. There was no check engine light for it. I first noticed my fuel milage went to crap from the computer dumping fuel to keep up with the always-on boost, and then noticed my actuator arm was no longer moving. It stuck closed so the car drove and felt fine. It was probably that way for several trips. Once I noticed the actuator wasn't moving and took a closer look I noticed the missing screw, and the stuck valve. A little leverage with a screwdriver popped the valve free and I grabbed a screw and locking nut that fit from my garage. I have an appointment with the dealer just so they can ensure it is adjusted right and replace with the OEM screw/nut.

Hopefully no harm done, but check your stop screw and watch that actuator arm. Always-on boost puts more load and heat on the supercharger and engine, plus your gas milage will suck. It could lead to bigger problems.

 

[Orchardbike]

Just noticed mine is the same today. I don’t know how long it’s been missing. The actuator is still operating (not jammed) and I haven’t noticed any change in performance or fuel economy. Are these bolts all set up individually i.e. the setting is different for each car or are they all set the same?

 

[saknibs]

I just checked my stop screw. I attached a pic of what one looks like. I measured the gap at 8.14mm.

 

[Orchardbike]

I just checked my stop screw. I attached a pic of what one looks like. I measured the gap at 8.14mm.
View attachment 74619

Thanks saknibs, are other peoples similar?

 

[geoffbland]

Thanks saknibs, are other peoples similar?

Mine is the same as yours - completely missing.
It's been missing for sometime (it may not have ever been there - I don't recall ever seeing it?) and has not ever been picked up as an issue at any service. Something to ask about when it goes into Silverstone soon.

 

[Orchardbike]

Mine is the same as yours - completely missing.
It's been missing for sometime (it may not have ever been there - I don't recall ever seeing it?) and has not ever been picked up as an issue at any service. Something to ask about when it goes into Silverstone soon.

Thanks Geoff, I’m sure mine was there originally, but when it fell off is a different matter. The engine (MPG/Performance) doesn’t appear to have been affected.

 

[virtualmacho]

Mine is still there. Around 6.1mm gap.

 

[scv]

Gap measures 5.0mm-

 

[scc.131.fe]

Added a link to this in the V6 Supercharger Reference Guide.

My Emira is stored off-site for a bit, will check on the bolt when I see the car again.

 

[CHEESE]

It's wild how drastically different this screw is on each car. Here's mine:

 

[Orchardbike]

It's wild how drastically different this screw is on each car. Here's mine:

View attachment 74769

Yes. It makes me wonder whether it’s doing much. Is it set with the engine running on a dyno or is it just screwed in and the amount depends on who’s installed it. Is it simply there to stop the piston bottoming out so it doesn’t stick shut as per RPM?

 

[ADC]

Yes. It makes me wonder whether it’s doing much. Is it set with the engine running on a dyno or is it just screwed in and the amount depends on who’s installed it. Is it simply there to stop the piston bottoming out so it doesn’t stick shut as per RPM?

Yeah, from your picture with no screw present (and still a gap) and everyone saying there seems to be no noticeable effect on running, I'd surmise it's probably just that... a backstop to prevent mechanical contact and damage at maximum travel.

 

[saknibs]

Still, I’m going to put Loctite on mine. Hopefully it will stay put.

 

[Orchardbike]

I plan to put a replacement screw in it tomorrow (if it stops raining!) and just randomly set it so it just lightly lifts it off the bottom of the piston.

 

[cryptovince]

Adding mine for comparison, July '24 build.

 

[Beachbum]

Still, I’m going to put Loctite on mine. Hopefully it will stay put.

I'd use a lock nut rather than loctite..... Just a thought

 

[Orchardbike]

I'd use a lock nut rather than loctite..... Just a thought

I’m doing both!

 

[saknibs]

I just finished securing my stop screw. It did not go as planned. I was going to remove the nut, put on some Loctite and replace the nut. I used a straight handle (not a ratchet wrench). With minimal force, the threaded rod broke off with the nut. I was able to retrieve the nut and remove the broken bit of rod. I decided the best remedy was to put the nut on the bottom of the threaded rod. To accomplish that, I had to remove the bypass valve. Thankfully, the two nuts holding it onto the bracket were easy to remove and I got the bypass value out of the way. Everything is back together, with Loctite. Hopefully it will stay put.

 

[Kzawilin]

It's wild how drastically different this screw is on each car. Here's mine:

View attachment 74769

Mine is the same as this too.

 

[Kimmax]

It's wild how drastically different this screw is on each car. Here's mine:

View attachment 74769

Mine looks like this, 2022 build