Rubber Intake Elbow - Collapsing off of Idle

[e30mclow]

I've been doing some tidy up items on my recently acquired 325i - https://www.r3vlimited.com/board/sho...d.php?t=417857


This weekend I removed the ICV and cleaned both it and the Throttle Body.
This improved the slight hesitation I was seeing when coming off of idle.


While under there, I noticed that the throttle body boot would collapse when I give it a shot of the throttle, and that this was at the same moment the engine would hesitate.


What's going on here?


The engine obviously isn't getting the air that it is requiring, but why?
I have a new OEM air filter.


Could it be MAF related? I haven't taken that apart and cleaned it yet.

[jeffnhiscars]

youve got a major intake restriction. Either your AFM is jammed, air filter is squirelly or someones cousin fell asleep in your intake.

Disassembled to the TB and check

[e30mclow]

It sure seems that way!

I’ve been complaining of it feeling dramatically underpowered vs my previous 325i, it seems to run out of juice up in the revs. Hard to know if it is the influence of the Audi’s boost after softening the edge of the m20’s performance.

[TobyB]

You're supposed to take the air filter OUT of the box before you install it, you know?

yust kiddink...

I like the sticking maf flap theory, myself, but around here, a mouse nest is equally likely...

t

[Todd Black 88]

This was common on s14 m3 s for a while. One of the aftermarket suppliers was selling intake elbows made of really flexible materials that would collapse under acceleration.