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Re: idle

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idle
boxsterd - 6 months ago
Hi does anyone know what's wrong or this is an easy DIY to fix? When the engine is warmed up and I'm at a stop sign the RPM needle goes back and forth between the 3rd and about the 4th tick mark.
It's a 2.7L base boxster. Could it be worn/dirty spark plugs? Thanks.
Re: idle
Anker - 6 months ago
Vacuum leak!
You said "when warmed up?. What about when its not?

Ultimately a vacuum leak will throw a code, but it might be minor.

G

Grant gee-lenahan-at-vee-eff-email-dot-net
Re: idle
MarcW - 6 months ago
Quote
boxsterd
Hi does anyone know what's wrong or this is an easy DIY to fix? When the engine is warmed up and I'm at a stop sign the RPM needle goes back and forth between the 3rd and about the 4th tick mark.
It's a 2.7L base boxster. Could it be worn/dirty spark plugs? Thanks.

Not plugs or coils.

More than likely AOS. When was this last replaced?

(BTW, I just had a new AOS installed on my 2002 2.7l Boxster around 3 years ago and 30K miles ago and apparently it is bad and causing a P1128 error code.The error code only appears after the engine is fully warmed up and when stopped and the engine idling.)
Re: idle
boxsterd - 6 months ago
AOS was probably last replaced around 50k miles ago.
IIRC it was replaced after there was massive amounts of smoke from the car.
There's no smoke. How much is it around to replace the AOS?
Re: idle
MarcW - 6 months ago
Quote
boxsterd
AOS was probably last replaced around 50k miles ago.
IIRC it was replaced after there was massive amounts of smoke from the car.
There's no smoke. How much is it around to replace the AOS?

That the AOS is the problem is not 100% certain. The 1st AOS failure of my 2002 Boxster started out with just the slightest idle variation. I futzed around some and because of the lack of experience with failing AOSs at the time -- this was early in 2004 -- and at some point with the engine idling tried to remove the oil filler tube cap. I could unscrew it but not pull it off the tube due to the excessive amount of low pressure the crankcase had. I thought a scavenge pump had gone rougue but after I spoke with the SM at the dealer where I bought the car he told me AOS, and advised me to *not* drive the car.

However, to get the car on the flat bed tow truck I had to start the engine and back the car out of the garage and this through inches of snow and through a snow bank -- courtesy of a city snowplow. The car got stuck in the snowbank and in rocking the car then the engine started smoking.

Just a bit of background to show that even with the seemingly mild symptoms/behavior the AOS can be the cause. It doesn't manifest the non-stop smoking until the very end. (In the 2nd AOS failure it took 2K miles and several days of driving then after a night at the hotel when I went to start the engine the smoke just billowed from the exhaust. The 3rd failure there were no pre-failure symptoms. The AOS was fine, the engine was fine, until I noticed a huge cloud of oil smoke.)

Yesterday in going through the Boxster repair invoices I came upon the invoice for the AOS I had done in Oct 2, 2014. The part (99610702304) was $156. A new vent line (99610714600) was necessary: $50. Also, 3 rubber o-rings (99970721540): $23. And 3 more rubber o-rings (99970734341): $12.30. Total parts came to $242 and labor was $480 (I don't know the hourly rate). Total (not including tax): $722.

Might toss in the mileage was 285,307 miles. (Currently the car has at around 320K miles.)

'course, this was over 3 years ago so prices may have gone up. And prices where you are may be (are probably) different (probably less...).

Let me add that my Boxster's AOS is *not* bad. That was the diagnosis when I posted my 1st time to you, but since then I have learned the AOS was not the problem with my car's engine.

I will be making a more detailed post on this later today after I pick up the car at 10am.

But I wanted to just let you know that the AOS may not be the problem with your car's engine.
BINGO!
boxsterd - 5 months ago
It was the AOS. The check engine light came on days before I took it in to the mechanic and I read the P1128/1130 OBD codes.
He did some kind of pressure test on the oil filler opening.
Replaced the AOS and all is good.



Edited 1 time(s). Last edit at 01/30/2018 04:50PM by boxsterd. (view changes)
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