New to me 02' 986 S
 

I recently picked up a 2002 986 S with 52K that has some issues. And I have some questions for those that know more than me.

The car threw a CEL in the first 50 miles (leading me to believe that the last owner turned it off prior to sale) I am getting a P0430 (Catalyst System Efficiency Below Threshold (Bank 2) and the car does not seem to run in keeping with what I would expect from a 250hp machine that weighs just 2900lbs. My gf's Mini C S will run with it for the most part. The main difference between the 2 is that I average about 25 to 27MPG when driving hers and I about 14.9 with 986 through my first 3 tanks of gas (seems excessive even considering my spirited driving style). It does not appear to be running extremely rich, as I'm not getting any soot from the exhaust. Howevreeee

I have purchased a set of used (40K) cats (with O2 sensors) to at least try and figure out if it is an O2 issue or the catalyst. I plan on putting new sensors in when I change the cats.

What oil do you recommend for this engine? I plan on replacing the plugs as well.

RMS is leaking. How big of a deal (yes, I'm familiar with the IMS issues on these cars) is it to run it until it's time for a clutch?

What would you check right out of the gate to ensure that you are meeting stock levels of performance? It handles beautifully, but the engine feels like not living up to it's potential. I doubt that I'll keep this car long term. It will likely be sold in favor of buying a car that has already been performance built.

All input is appreciated!

Cheers!

Ross

You're not going to get good mileage with it. For me, 17 around town and 22 highway keeps me happy.

As to the secondary cats, swap them out and see what happens. It's not a big job. Test it first without the new sensors.

The RMS is another issue, are you comfortable watching it leak oil?

I would probably bet it is an O2 sensor that is your issue, low gas mileage, etc can be caused if the second O2 is bad, the car never reads that it is warmed up and stays in the warmup loop (runs rich) trust me, when the car is running right if feels like more than 250hp

It's the primary cats. The secondary cats are unmetered...

As to the RMS - I have turned wrenches on a number of flat engines but they were all made by Continental and Lycoming. I am accustomed to seeing oil weeping from these types of motors. My car is not leaking so much that it's marking it's territory (nothing on the ground). I ride a 40 yr old Triumph as well, so the Porsche seems quite tight to me in terms of fluids...:D I just want to make sure that the only issue to come from a weeping RMS is the mess.

Good to know. Right now my 13 yr old GS400 with 203,000mile would beat my S in a drag race by a large margin.

What you say about the the richness make sense as I get a rather significant uptick in performance on cool nights. I realize that engines always run better in cool weather, but going from an
OAT of 80 df to 65df should not make that big of a difference, but in the case of my car, it makes very a noticeable difference...

It can damage the clutch if the leak is such that it fouls the clutch before making its way to wherever you are seeing it. So not catastrophic, mainly just hastening the inevitable clutch replacement. Unless the car already has a new clutch, in which case you could be reducing the life of that clutch by a lot. But probably, if the clutch had been recently replaced, the RMS leak would have been tended to at that time as well.

Mileage can vary widely depending on a number of facotors. I get 24 mpg on the hwy, 17 mpg around the city, and 12 mpg on the track. "Spirited" street driving can easily yield 14-16 mpg.

A Mini Cooper S should be somewhat slower than your Boxster S. I have a base Boxster and a 2002 MCS with the JCW supercharger upgrade to 200hp and my base Boxster will stilll outrun the MCS.

Do a search on oil recommendations and you'll find several very long and quite passionate threads on the subject.

The RMS leak isn't an issue if you can live with it. Just make sure that the oil lever doesn't get too low.

This was my thought. My car is only ~250lbs heavier than her MCS (lovely and fun machine BTW), but with 87 more HP I would expect a dramatic difference in performance.

There's obviously something wrong with your vehicle. No Mini Cooper should be able to out accelerate a boxster . Let alone an 'S" . I own/owned both .

He doesn't mention the color but perhaps it's not yellow? That could explain it...

Actually, before acquiring my 986 S, I can recall destroying the egos of 2 base model Boxster owners with my Chickee's MCS 6spd on 2 separate occasions. A stock base Box (2.5L) with tip versus a stock MCS 6spd is not a foregone conclusion...

Arctic Silver with grey top and interior; perhaps that's what's causing the CEL...

Just ran across an article while searching for something else that may be of interest vis this subject.

Callas Rennsport

Many thanks!

--------------------------------------------------------------------------------

I had the same thing. Engine Light diagnosis code # P0430.
I stopped at Mobil for gas twice, and had a three hour drive, and ran it like it was stolen. Light came off. I am going to dump a bottle of techron too, why not!?

"Porsches are meant to be driven not polished"

No affiliation, just making my point :)
S•CAR•GO Racing

I'd like to toss this question out to the forum to get a "second" opinion.

One of the local P-dealers told me that an oil leak may be an early symptom of a deteriorating IMSB. Has anyone else heard this or is the dealer just blowing smoke my way?

I'll confess my ignorance. If the above is true, can one mistake a leaking RMS for a IMSB-based link?

Thanks

That is true but in most cases it will be a RMS leaking. The only way to identify the source of the leak is to drop the transmission.