Smoked and choked - First Boxster problem = AOS?

[jb92563]

My First Boxster part failure was a ridiculous pouring, billowing of smoke.

All was perfectly normal on my drive to work yesterday, but upon leaving for the day the startup produced a momentary cloud of smoke....embarrassing but not totally unheard of.

I carried on with my 15 mile drive home with the odd trace of smoke at a light but no indications of anything on the guages and warning lights.

I had read that the AOS was essentially harmless and figured no problem making it home.

Then I got to a light half a mile from home and all hell broke loose.

The idle was becoming a bit erratic, first low, then high and then the smoke came billowing out like I never even thought was possible.

Its was about 5 times more than the smoke trails they use at airshows.

It was such a ridiculous amount of smoke I started laughing because traffic on both sides of the road came to a stop to see the spectacle and folk behind turned on headlights.

Then the motor started running very rough and the engine light would come on flashing for a brief second or 2 then go away as I limped home rather slowly.

I stopped, trying to decide if I should get a tow the last 500' home.

The its smoke subsided for a moment and started running OK so I drove home and got it in the garage.

I'm pretty sure its the AOS but hard to imagine this experience until it happens to you.

I hope nothing else gets damaged in the process because it seems like the engine was running more on oil than fuel.

I'll check how much oil I lost in the process and report any other issues.

So much for my weekend Auto-X....damm

[kk2002s]

You just wish that a component like this could allow some ability to limp home and some warning.

So from those who have done this - If one had a new AOS part and the tools, could this be fixed on the side of the road.
Circumstance going on long trip - take the part as a spare in case

[jdraupp]

From what ive heard it depends on how ruptured it is. On the total meltdown side the aos can cause hydrolock. Which is bad. And I think means a rebuild.

Because you have to go in from both sides id say not a roadside repair unless your kit includes a jack and jack stands. I'm a fit fan but when I got mine replaced I paid for it to be done.

[seningen]

Originally Posted by kk2002s

You just wish that a component like this could allow some ability to limp home and some warning.

So from those who have done this - If one had a new AOS part and the tools, could this be fixed on the side of the road.
Circumstance going on long trip - take the part as a spare in case

Realistically -- no. Not that it's impossible, but it's just that its a real pain to do.

I'd pay the AAA -- get it some place safe and do it there.

I'm not 100% sure -- but I think you might be able to remove the connection back to the intake and try to build a catch can if there isn't too much oil "flowing".
I don't think you can block it -- the back pressure probably would either choke the engine or it would blow the "plug".

Remember it doesn't take much oil to create quite the smoke screen.

Don't be fooled tho -- I would only drive it long enough to get home.

Also note -- I've never tried this, YMMV, and I'm not responsible for the consequences.

Mike

[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?

[patssle]

AOS related - is there a lifetime expectance for them? Is 5 years and just 16,000 miles on it too soon to die?

[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.