Smoked and choked - First Boxster problem = AOS?

[Mark_T]

Given the consequences of a hydro-locked cylinder, I will shut it down immediately and have it towed home when this happens to me. it hasn't yet, but I'm sure at some point it will.

[jb92563]

I took a preliminary look and ordered a new OEM AOS from Pelican.

Pelican says you can remove the line to the intake and block the ports for an emergency limp home if necessary.

I found I had lost 2.5 quarts of oil in the process and was on the bottom digital indication, but no oil light yet. Makes me wonder when would the oil light come on?

I hooked up the Durametric and noted all the codes indicating misfire on nearly all cylinders and Oxygen sensor faults.

I would think the spark plugs may also look pretty sooty but I will see once the new AOS is in and the remainder of the oil is burned out of the intake whether I need new plugs.

Hopefully the catalytic converter and Oxygen sensors survived.

There was no oil leakage anywhere except some misting on the bumper around the exhaust.

I stuck my finger in the intake tube from the AOS and it was very oily so definitely too much oil coming out from the AOS in to the intake.

The car has 72K miles and no record of the AOS being replaced before so it lasted a good long time I suppose.

I usually say that every failure is an opportunity for an upgrade but I don't see that opportunity here.

Perhaps if I take the old unit apart and discover a mode of failure, maybe there is a way to prevent, modify or at least get a warning of impending failure.

Since the car will be down for the week waiting on parts I should probably complete my headlight projector/dragon eyes project

[jb92563]

Originally Posted by Mark_T

Given the consequences of a hydro-locked cylinder, I will shut it down immediately and have it towed home when this happens to me. it hasn't yet, but I'm sure at some point it will.

I don't think the AOS could provide enough oil to cause a hydro lock since it does not really have a reservoir that would hold that much oil. Im just guessing though, but it did cross my mind as I was watching the complete white out in the rear view.

I also enjoyed seeing the slipstream of car aerodynamics in the smoke...interesting effect. I'd wish I had filmed it for later review.

[jb92563]

Update-

Amazingly I ordered a new OEM AOS from Pelican on Friday with the free ground 5 day delivery and amazingly it arrived the next day, Yesterday. That's why I like to support these guys with my business. (And the DIY articles)

So I proceeded to remove and install the new one.

It took 2 hours, most of which was spent getting the clamp removed and wrenching blind as I could not see where I was going with my arm in the only opening that had a line of sight on the target bolts and camp and had to do it by feel alone.

A mini vise grip was the perfect tool for removing the bottom clamp after unscrewing only one wire harness clamp and pushing it aside.

So I started the car and ran it for a bit to clear the remaining oil in the intake and after 15 minutes in the driveway there is little smoke anymore.

I checked with the durametric and cleared all the codes.
None of the old codes came back but a new code P0507 has come on and the idle has become erratic and after reving the engine it overshoots the min idle setting and stalls. The erratic idle started right after I cleared the codes.

No other codes, no warning lights, no smoke, just the erratic idle and P0507 code.

I'm beginning to wonder if in pulling on a few cable trying to get the new AOS in place I might have dislodged something.

Anyone know where this "Idle Air Control" unit might be?

[Jager]

Originally Posted by jb92563

Update-

Amazingly I ordered a new OEM AOS from Pelican on Friday with the free ground 5 day delivery and amazingly it arrived the next day, Yesterday. That's why I like to support these guys with my business. (And the DIY articles)

So I proceeded to remove and install the new one.

It took 2 hours, most of which was spent getting the clamp removed and wrenching blind as I could not see where I was going with my arm in the only opening that had a line of sight on the target bolts and camp and had to do it by feel alone.

A mini vise grip was the perfect tool for removing the bottom clamp after unscrewing only one wire harness clamp and pushing it aside.

So I started the car and ran it for a bit to clear the remaining oil in the intake and after 15 minutes in the driveway there is little smoke anymore.

I checked with the durametric and cleared all the codes.
None of the old codes came back but a new code P0507 has come on and the idle has become erratic and after reving the engine it overshoots the min idle setting and stalls. The erratic idle started right after I cleared the codes.

No other codes, no warning lights, no smoke, just the erratic idle and P0507 code.

I'm beginning to wonder if in pulling on a few cable trying to get the new AOS in place I might have dislodged something.

Anyone know where this "Idle Air Control" unit might be?

Do you have a Bentley manual? Page 24-2 shows location. It's attached to the side of the Throttle Body housing. Make sure your electrical connection to the throttle body is good? Did you clean the throttle body?

[jb92563]

Originally Posted by Jager

Do you have a Bentley manual? Page 24-2 shows location. It's attached to the side of the Throttle Body housing. Make sure your electrical connection to the throttle body is good? Did you clean the throttle body?

I did not clean the Throttle body. Is that something I should do?

I imagine its never been done before.

I have a Bently manual and see where that unit is now, thanks for the reference.

I wonder if the oil from the AOS failure has somehow fouled it.

After reading the Bently manual I read that if you reset the codes the DME does a relearning process but you have to leave the ignition on for 1minute without the car running and then turn the ignition off for 10 seconds.

After I did this the idle has now settled to a regular steady idle and does not stall when revving.

Still some oil to burn out of the intake though but I want it to run steady before I take it on the road.

I think a while longer in the driveway when its up to temperature and it might be OK.

I'll durametric it to see if there are any faults now.