Bad idle 928s4 1988 ... Even staled !
04-16-2016, 12:53 PM
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Bad idle 928s4 1988 ... Even staled !
Has no problem and now when the engin is hot (working hot) the idle cant stay still at 450rpm...
And staled 5 Times in 10 min ! Mecanic tryied to clean intake valve... Now the engin doesn't stall but idle is'nt stable (1000-200rpm) and winding up and down?!?
Any body got these problèmes OR SOLUTION ?
Thanks !
And staled 5 Times in 10 min ! Mecanic tryied to clean intake valve... Now the engin doesn't stall but idle is'nt stable (1000-200rpm) and winding up and down?!?
Any body got these problèmes OR SOLUTION ?
Thanks !
04-16-2016, 06:35 PM
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Your idle speed is computer controlled and should compensate for things like when the A/C is on. There are no idle speed adjustments. The idle stabilizer valve located way down under the intake manifold electrically is opened and closed to let air into the engine....they get worn or fail and the computer no longer can maintain the correct idle speed which is higher than your 450 RPM....
Your mechanic clearly knows NOTHING about the 928 S-4....which will cost your lots of money and grief.
Your mechanic clearly knows NOTHING about the 928 S-4....which will cost your lots of money and grief.
04-17-2016, 11:20 AM
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As shown above the list of things to do while the intake is off is rather long but if you really want your car to be reliable, run correctly and make horsepower........that is also when you can repaint the intake.....but then the camcovers will look bad 
But that adds other jobs to do while in there.
But that adds other jobs to do while in there.
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04-18-2016, 10:04 AM
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Your idle speed is computer controlled and should compensate for things like when the A/C is on. There are no idle speed adjustments. The idle stabilizer valve located way down under the intake manifold electrically is opened and closed to let air into the engine....they get worn or fail and the computer no longer can maintain the correct idle speed which is higher than your 450 RPM....
Your mechanic clearly knows NOTHING about the 928 S-4....which will cost your lots of money and grief.
Your mechanic clearly knows NOTHING about the 928 S-4....which will cost your lots of money and grief.
Mécanic is prety good since i hade no idéa what was the problem and he when direcly for the ISV cleaning.
Since the gasket of oil knozel seam to be worn and causes à leak a top of the motor... The intake may néed to be removed at the end of this season. I understand that the intake refresh will have to be done at the same time... Right ?!?
How much labor time should this refresh and to motor gasket should it take for a good mecanic use to the 928s4 ???
Should the gaskets of valve convers be change at the same time... Seems thèse seals are liking a bit too...
Thanks guys, you are infos gurus !!!!
04-18-2016, 12:47 PM
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If some of your plug wells are full of oil you need to be rectifying the problem now I would politely suggest.
As Speedtoys has already suggested you may be sat on a crock of failing plastic and rubber in and around the inlet manifold by the sound of it. Very common scenario, no short cuts to salvation and can make the difference between a 928 that runs as it should and a complete dog.
A good professional can have the inlet manifold off and back on in a day or less, the cam covers about 2 hours each, add a bit for the unexpected and a couple of days total effort may suffice.
As Speedtoys has already suggested you may be sat on a crock of failing plastic and rubber in and around the inlet manifold by the sound of it. Very common scenario, no short cuts to salvation and can make the difference between a 928 that runs as it should and a complete dog.
A good professional can have the inlet manifold off and back on in a day or less, the cam covers about 2 hours each, add a bit for the unexpected and a couple of days total effort may suffice.
04-18-2016, 03:41 PM
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If some of your plug wells are full of oil you need to be rectifying the problem now I would politely suggest.
As Speedtoys has already suggested you may be sat on a crock of failing plastic and rubber in and around the inlet manifold by the sound of it. Very common scenario, no short cuts to salvation and can make the difference between a 928 that runs as it should and a complete dog.
A good professional can have the inlet manifold off and back on in a day or less, the cam covers about 2 hours each, add a bit for the unexpected and a couple of days total effort may suffice.
As Speedtoys has already suggested you may be sat on a crock of failing plastic and rubber in and around the inlet manifold by the sound of it. Very common scenario, no short cuts to salvation and can make the difference between a 928 that runs as it should and a complete dog.
A good professional can have the inlet manifold off and back on in a day or less, the cam covers about 2 hours each, add a bit for the unexpected and a couple of days total effort may suffice.
04-18-2016, 03:43 PM
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This is a common trick with mixed results. My mechanic explained that the ISV door rides on a bushing, and once that is shot it does not really get better with lubricant.