[Mk2] [NA] RPM related rattle around the intake

[I_Tristan]

Hello everyone,

Since I've owned my MR2 (more than a year now) I've experienced a rattle in the engine bay from around 1750-1900 RPM. The sound is starting to bug me more and more, first I thought it was the exhaust but it clearly comes from the intake part of the engine (3SGE). (prntscr . com/hhczhl)

I will include a video where you can hear the rattle, its a really metalic sound.
www . youtube . com / watch?v=ElnsC7fWmTU

I really hope someone can help me.
P.S. sorry for splitting the links, won't allow me to post otherwise.

Thanks in advance,

Tristan

[I_Tristan]

I have not found a solution for this yet, any help would be much appreciated....

[tottacrolla]

Valve clearances or it might be TVIS if it is fitted.

[I_Tristan]

Thank you very much for the info!

I plan on removing the intake to check, does the intake have a seal where the valves are situated? If so can I reuse the seal?
How can I see if its fitted with the TVIS system?

[tottacrolla]

I'm sorry Tristan but you may be in out of your depth and my advice would be to put up with the noise until you can find someone to diagnose / fix it for you.

[tottacrolla]

I'm sorry Tristan but you may be in out of your depth and my advice would be to put up with the noise until you can find someone to diagnose / fix it for you.

[abovetherim]

Difficult to tell from video but the sound seems to be more prominent near the intake.

The square like bit of the intake has butterflies in it that are moved at certain rpm to adjust the length of the intake path. These flaps are controlled by a lever attached to a vacuum powered diaphragm.

Now the rattle could be as simple as the linkage for this having some play. It could be loose butterfly or shaft.

Under the intake are a couple of support brackets that could be loose. Also under there are a couple of vacuum valves mounted that could be loose.

Or it could be valve clearances.

To narrow down the area of the rattle you can use a length of hose to listen with or touch a long metal bar to different points on the engine with the other end touching your ear.

Hope this helps in the process of diagnosis.

Oh and if you whip open the intake you should replace the gasket though if in not too bad condition you may get away with reusing old one with a bit of rtv silicone.

[SonicSW20]

NA's don't have TVIS, they have ACIS.

Try manually actuating the ACIS (move it by hand) and see if it still rattles with the ACIS in a different position.

[Dale_V]

It could be a heat shield or a bracket. theres 2 support brackets from the block to inlet manifold, and im sure theres also a little shield under the manifold too, it could have a hairline crack, loose bolt etc

https://www.youtube.com/watch?v=ElnsC7fWmTU

[I_Tristan]

Okay, so update time. I took the acis valves off, replaced the gasket, swapped the acis unit for another one, yet the problem continues to exist. Nothing noticibly changed. same rpm range, same sound. I've checked, the system does still work, you can see the valves open up above 5100rpm. Also have made sure that all valves move at the same time, by placing a metal bracket in between them since the regular clip didn't fix anything.

I'm out of ideas apart from leaving the valves out all together...

Any help?

[androo007]

shims in spec?