Quote:
Originally Posted by Sdav86
I guess that means I need to track down an intake leak or try a different maf. The intake pipe coming from the air box to the tb is really hard to slip over the tb. Is there a good solution to fix this? I thought about using my heat gun to soften up the hard plastic and re-mould it to the front of the tb, but I wasn't sure how successful I'd be at doing that.
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Most likely a vacuum leak. I'm somewhat confused by your comment that your tb boot is hard to fit over the throttle body. That boot should be a 90ﾟ rubber from tb (i use a serious clamp designed for turbo tubing interface) which then connects to hard tube (plastic/composite or metal if someone has altered induction)...and trajects towards the airbox after at least 1 more 90ﾟ bend. Between the next 90 (and if still stock) there is a component to the intake pipe called the "snorkel" and it is basically a way to mitigate sound and potentially create some resonance which may have been removed on your car. Get The Pelican book on the Boxster as it is an invaluable resource. I did my entire swap using that book as manual.
In general, the most common areas for vacuum leaks are under the intake tubes (top of engine) themselves---there's several vacuum lines and I would feel around our get flexible mirror under there to see better. (You will be standing on your head here a bit...ie hard to get close enough visually) take your phone and get several pictures to see if anything askew)
One other trick is to get a can of starting fluid and with the engine running (if it's running rough) spray lightly starting fluid around vacuum hoses and vacuum hose (under plenum) connections and throttle body interface and if the rpms change at all you know that you have a potential vacuum leak. The spray will dissipate quickly. Steer clear of open flame. Obviously don't wanna do this round any kind of open spark but your spark plugs and coils packs are down to the sides of the engine so this should not pose a risk. Share what you find. Hope this is helpful.
Bottom line, Any deviation in rpms as result of you spraying tells you that you've got compromised induction either secondary to bad vacuum or pressure.
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