Getting High

[RascalRuss]

Guys,

My boxster is running very rich!!

I was driving down the motorway a few weeks back, it was reasonably warm weather. I then hit stand still traffic, as I came to a halt, disengaged the gears, and let the engine idle, I noticed it running quite rough (felt like misfiring), I looked at the dash to check a few things and noticed my idle revs were not running at their usual 850RPM, but instead dropped to 500RPM.

A few moments later, the engine light started flashing; this lasted around 2 mins, and then went out.

The engine light has not been on since, but I have noticed that the exhaust fumes are extremely rich in smell. The revs still seem low, and the engine still run reasonably rough.

Additional notes are that at cold start up, when the engine is running on increase revs, its seems to only run rich (no sign of rough running), then when it’s warm and drops its revs, its starts acting rough again. Also, when driving along, it’s seem to run fine (I guess it’s still rich at this point)

Before I have to folk out for a check up, is there anyone who has any ideas of anything I could check to try and remedy the problem myself

It’s a Boxster S MY00

Cheers

[RFM]

Let check the car on fault codes, it's the cheapest way to go after all.

[RascalRuss]

I agree, but with my day clear tomorrow, I was thinking on having a tinker myself first before paying out for Porchse to play. If anyone knows what could be causing this then I can take a look...........dirty MAF, loose coils, etc??

Cheers

[Ross1]

Try cleaning the throttle body! It's easy to do and if it doesn't work you aren't out anything.

[usaf-lt-g]

Try cleaning the throttle body! It's easy to do and if it doesn't work you aren't out anything.

Lol... well... It's "semi-Easy" to do. The bolts on the underside of the throttle body to the intake are a bit of a pain to get off. and reattaching the intake pipe to the throttle body is also a bit of a "work" :) I soaped mine up, and then struggled for a good 20 minutes in different positions making weird faces trying to get mine back on. Just a pre-warning. Other than that it's a piece of cake.

[RascalRuss]

haha....funny faces here we come!!!

Could it also be the MAF and/or O2 sensors causing this.......or would they throw up a permenant engine light??

[Loren]

My advice is do not replace anything until you know what the fault code(s) are.

Without fault codes you are just guessing.

[RascalRuss]

ok, thanks Loren

I cleaned the throttle body today, seems to be oil in the intake pipes, quite a bit too, is this normal?

[Topless]

ok, thanks Loren

I cleaned the throttle body today, seems to be oil in the intake pipes, quite a bit too, is this normal?

Sounds like oil change overfill or failed AOS.

[usaf-lt-g]

ok, thanks Loren

I cleaned the throttle body today, seems to be oil in the intake pipes, quite a bit too, is this normal?

Sounds like oil change overfill or failed AOS.

Ditto the AOS. I replaced mine about 3 months ago. Oil in the intake pipes is almost a for sure sign. You may have codes on an OBD II, but chances are, if then ENG light hasn't turned on, there might not be anything there. I'd deffinately make an effort to replace your AOS though. There's a complete guide on here on how to do it. If you have an E-Gas version, you don't need to order the extra J-Pipe.

[RascalRuss]

Hi Guys,

Whats AOS stand for and can you point me in the right direction of the guide to replace this

would this also cause the misfire maybe due to faild spark plugs from the oil?

many many thanks

Russ

[White987S]

Hi Guys,

Whats AOS stand for

Russ

Air

Oil

Seperator

[RascalRuss]

Hi All,

I have now had the fault codes from the memory, and glad I took your advice now, cause there were 8 of the little buggers!!! Ok here we go,

P1119 - Oxygen sensor heater ahead of cat. conv., bank 2

P0150 - O2 Sensor ahead of cat. conv., bank 2

P1133 - Oxeygen Sensing adaption, lower load range, bank 2

P0300 Misfire detection (total)

P0306 - Misfire, cylinder 6

P0304 - Misfire, Cylinder 4

P0305 - Misfire, Cylinder 5

P1130 - Oxygen sensing adaptation , idle range back 2

Just to help give the whole picture, current running condition, starts ok first time but smells very rich. ONce settled (warmed up) in to idle, it only idles arounf 500rpm and you can feel it misfiring, still smells very rich at this point. During driving, you can feel the misfires as you accelerate. The exhaust is black with sooty deposits.

The car that took the faults off the memory for me said that he could not pin point the exact problem, and he doubted it would be all caused by an O2 sensor and needed it in to take a good look at it.

Can you guys help with the disgnosis at all?

Many thanks

Russ

[RascalRuss]

PS - Just reading the other post by someone on the AOS and decided to take the oil filler cap off during engine running, and it sounded very noisy, could hear something going on in there, like bellowing, you could literally hear the engine, not sure if that is normal and if not if the AOS broken would cause only one bank to mis fire?

[RascalRuss]

Any idea ladies and gents??

[Loren]

Still sounds like a bad AOS to me...

[Jake Raby]

If you have oxygen sensor faults the ECU will try to compensate for them by ADDING fuel. This is why the engine runs rich.

I'd say you are in need of some oxygen sensors or at least one.

[RascalRuss]

would this cause the misfiring on all back 2 (cylinder 4, 5 and 6)????

[Topless]

would this cause the misfiring on all back 2 (cylinder 4, 5 and 6)????

Looks like bank 2 is pretty fouled. Could be several things like .... Bad AOS. Didn't someone suggest this before?? Other possibilities include bank 2 head gasket, bank 2 injectors, bank 2 O2 sensors fouled. Your previous post suggested significant oil in the intake and throttle body. Bad AOS or oil overfill could certainly cause all of your symptoms including fouled cyls in bank 2. If it were my car I would check my oil level, yank the AOS quick, clean the intake and TB, clear the codes and as long as I don't have a flashing CEL from deeply missing cyls., drive her to see if the fouled cyls clean up. Or find someone with durametric or PST2 software to get a more in depth diagnosis. Further damage could occur with fouled cylinders, O2 sensors and or fouled cats so pay close attention. Good luck.

Edited November 8, 2008 by Topless

[RascalRuss]

guys, can you point me in the direction of this guide for changing th AOS, I cant find it, done a search on here

[RascalRuss]

its ok, its all done, just give the spark plugs a clean down and clean the o2 sensors.

If all is well, I will take the cats off and wash tehm out too at some point just in case, its its still bad, then will let you know

Changing the AOS was actually not a bad job as I read in some of the posts, mainly cause I used a thumb screw jubliee clip in replace of the clamp style one, it was easy to screw up with the wheel off

cheers

Russ

[Loren]

I would NOT clean the O2 sensors with anything. Almost all cleaning solvents will damage the O2 sensors.

Use the heat of the exhaust - in most cases it will burn off.

[RascalRuss]

Guys,

I have now replaced the AOS, cleaned the spark plugs (the bank 2 spark plugs were black, bank 1 were not to bad), put it all back together, started it up, but stil the same, if not slightly worse.

Its mis firing loads, CEL light is flashing madly

one things that has improved though, is it now idles at 850 and not 500 as before.

Any suggestions guys?? Do I need to replace the O2?

Cheers

Russ

[Loren]

You need to look at the O2 voltages to determine that.

Do you still get smoke? If so, then you haven't burned off the previous oil yet.

[RascalRuss]

Hi Loren,

Smoke isnt the word, I would say more smoke, its like a white smoke. However, it does not seem to smell rich anymore, well not as much anyway.

Do you think I need to take it for a good drive to get rid of the oil and see what happens?

Cheers

Russ