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YOUR RESEARCHCable throttle 3.4 Idle control valve
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Adjust amount
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Read evidence and context
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Suggestion · Original poster
So the idle valve oscillates back and forth really quickly, adjusting the amount on air going in at idle.
Leading evidence: 'Adjust amount' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Adjust amount' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
I was always cleaning ICVs and MAFs on my old XR3is and RS Turbos.
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Suggestion · Original poster
1) use a 9v battery, connect one terminal to the middle pin then the other to one of the other pins.
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Suggestion · Original poster
Air leaks can be found by building a smoke machine and pressurising the intake - I built one using using a soldering iron, glass jar and a tyre inflator.
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Suggestion · Original poster
Air leaks can be found by building a smoke machine and pressurising the intake - I built one using using a soldering iron, glass jar and a tyre inflator.
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The cable throttle 3.4 996 and 2.5 boxster has an idle control valve that lets by some air to stop it stalling at idle.
Later electronic throttle cars can just move the throttle to adjust this.
So the idle valve oscillates back and forth really quickly, adjusting the amount on air going in at idle.
Idle should be 950 rpm with air con on and 650 with it off.
If its over 1000 all the time then you have an air leak or stuck open idle valve - too much air is getting in after the MAF.
Air leaks can be found by building a smoke machine and pressurising the intake - I built one using using a soldering iron, glass jar and a tyre inflator. I found an air leak at the AOS with this - but the high idle remained.
If no air leak is showing then you might have a stuck idle valve.
Its easy to remove, on the side of the throttle body, I think T30 bolt be careful not to lose the paper gasket.
You can do these tests:
1) use a 9v battery, connect one terminal to the middle pin then the other to one of the other pins. It should snap round each way. If not the solenoid might be dead or the actuator just seized.
2) It should move easily when you flick with a screwdriver.
3) test the resistance - usually they fail open circuit - if it fails this then it will be toast.
If it yours is seized then you can dismantle it. If you force it then you risk bending the inner moving part.
Spray it up with carb / intake cleaner around and it might free up.
Otherwise you need to dismantle it.
The idle valve is visually similar to that fitted to BMW M44 engined cars. The Bosch part number is one digit apart. The BMW part is about £70 cheaper than the Porsche part.....
There is a guide here to taking it apart, but you just remove the little pin and rotate the two halves. Clean up all parts and put back together.
http://www.318ti.org/forum/showthread.php?t=27697
On mine the o ring was red and bit hard to get back in as it swelled because I got carb cleaner on it. Also the spring washer does its best to stick to magnet and not stay in position.
Doing this completely freed it up and fixed my idle.
If you mess it up then cp4l do the BOSCH idle valve for £150...
That's a great write up. Thanks. It's folk like you that make this forum such a great resource. The forum owners ought to send you some beer tokens to say thank you. :thumbs:
Oof! Should have gone to a specialist mate.
Just kidding. Excellent post Wasz and will no doubt help others in the future.
Heck I'm even tempted just to clean mine anyway after reading that.
I was always cleaning ICVs and MAFs on my old XR3is and RS Turbos. It was always nice when it smoothed things that little bit.
Anyway, great info and another valuable little thread. :thumb:
I'd be interested know if anyone has had success with the much cheaper BMW part if theirs was beyond repair?? Is it just that good old Porsche tax again?
It's got to be surely. :dont know:
