David C2S

i have two major issues with my car. a week ago my CEL came on and i was told by my dealer that it was carbon build-up, a job requiring 10 days, removal and splitting of the block, etc to clean the heads because the secondary air injectors have no air flow - an $8K proposition. since getting the car back to search for other solutions i have found buddles of oil under the right side of the car. i added 1 qt of oil and since then have had a bruning smell in the car and smoke from the right tailpipe - perhaps too much oil? yesterday the oil pressure needle was moving between 3-5 while driving, and last night would drop to 1-2 with the warning light coming on, then going off. HELP!!!!

Davies

David,

If you look in the archive there's tons of stuff on carbon buildup.
It's not really a gigantic mechanical problem except when it comes time
to get your emissions tested. Dealers are pre-programmed to say you need a
valve job to alleviate the problem. Some of the people on this board
have discovered that for about 10% of what your dealer quoted you,
you can have the carbon buildup in the secondary air injectors cleaned out.

As far as your oil pressure, that's another story, which I'm totally unqualified
to offer advice on. Though I know someone here'll offer some sage advice.

Good luck!

Jon 'Bama

first stay away from the dealer.

Even though both Atlanta dealers are excelent. Craig at Ellis and Jack at Hennesey are both very good/great Porsche Tech who really know their stuff paying $98/hr and book rates for a job this big is crazy. Seek out independant help.

Call Peter at Performance Imports on Peachtree Industrial. (770) 451-9171 Their Lead Porsche Tech Bob Sanderson (He was on the Racers Group pit crew that won at LeMans a few years ago) is every bit as good as the other guys and their rates are much lower ~75/hr IIRC and they bill actual not book time so it should cost considerably less. I have seen numbers posted here from 4-5k to fix the Carbon issues. Alternatively Jack Lewis Enterprises in Norcross is a very well respected shop, in fact in the older 911's many consider Jack "The Man" I have used Performance Imports with my Porsches and been very happy.

Good Luck


Jon

Dave Crellin

I second the comments about avoiding a dealer for the carbon build-up fix, if that's the route you go. Rates are way to high.

STLPCA

Matt
What is the $800 fix? I thought the root cause of the SAP carbon buildup was worn valve guides & the carbon buildup/CEL were just symptoms of that problem.

Davies

Dan,

I remember reading a thread on this. Someone's independent mechanic actually
used pipe cleaners and some type of gunk cleaner and cleared out the secondary
air injectors and fixed the carbon buildup/CEL issue. Took ten hours or so of labor,
hence $800. I'm told valve wear can cause carbon buildup...but I know that many CELs are triggered by this that have none of the traditional signs of
worn valve guides (high mileage, oil consumption, smoking etc...). From what I understand there's a design flaw in the secondary air injectors (too narrow??) that causes them to clog easily and I think doing a valve job to fix that is, IMVHO a tad over- the-top.

Randall G.

Hey Dan,

Yup, supposedly it's worn worn valve guides that lead to SAI port clogging. But--as Matt points out--most people don't have the traditional signs of worn guides, and would never know they had a problem if the SAI error hadn't set the CE light. Personally, if I don't have excessive oil consumption or smoking, there's no way I'm forking out $5k (+) for a valve job to fix something that's only in effect the first couple minutes of engine start-up. I'd be looking at one of the alternative fixes (e.g., port cleaning, modified software that ignores the clogged SAI code).

Randall G.

oops

David C2S

thanks for these replies, guys. Jon - I will definately check out Performance Imports. I have driven by them many times, but never knew anything about them. the only smoking from the car has been the last few days after the 1 qt oil add. i just figured it was some of the carbon burning off as i've been driving the car a lot harder to do that.

any ideas on the oil pressure guage movment and oil pressure warning light coming on/going off? could this be from too much oil? the oil level guage never moved to horizontal after proper warm-up and at idle, post oil add.

911-TOUR

Your scavenge pump is probably dying/dead. I'm not sure how easy it is to fix this, but I've seen it on 911s before. I'd be very careful driving the car until this is remedied. In fact, I'd have it trailered to the shop.

sean

David C2S

Sean - what is a scavenge pump? i've never heard of this. also, what sympotoms draw you to this conclusion?

chris walrod

the oil pump (for dry sump applications) have two (at least) chambers, one for oil pressure, and the other for oil scavenge. Basically the scavenge side of the oil pump pulls or sucks oil out of the engine, returning it to the oil tank..

I myself would be surprised to hear of a 964/993 oil pump failure. Of course an oil pump that ingests bits and pieces from a huge engine failure will be trashed, more than likely.....

chris walrod

One more thing, have a shop connect another oil pressure gauge to verify the oil pressure issues you seem to be having.. Always a good, and sometimes cheaper idea to double check your instruments before digging into an engine..

Randall G.

With regard to your oil pressure:

*3 to 5 when driving is normal. If you're talking erratic movement, that might suggest a bad sender.
*1 to 2 when idling is normal.
*Your oil pressure reading is proportional to engine speed. High engine speed, high oil pressure. Low engine speed, low(er) oil pressure. The oil pressure is also higher when the oil is cold.
*The warning light coming on is not normal. Though, believe it not, the owner's (or is it the shop?) manual says it's okay to have the alarm come on when idling. That said, I couldn't tolerate an only-when-idling low pressure alarm on my own car. Kinda' like the manual saying 1 quart of oil per 600 miles is normal.

It's possible your sender for the low pressure alarm is failing. As Chris suggests, you can have a shop hook up a pressure gauge to verify the reading.

A really low idle could also cause the low pressure light to come one.

The oil leak may just be...an oil leak. The burning smell would be the oil leaking on the heat exchanger. Very common on 911s. Especially the valve covers leaking onto the heat exchangers. Are you sure the smoke is coming from the right-tailpipe, and not in the area of the right-tailpipe?

Regarding your oil level. Have you checked it with the dipstick? With a proper dipstick reading, you should also have a reading on your gauge. As you know, the gauge won't read unless the oil is warmed to normal operating temperature.

Oh, and like Chris, I'd be surprised if the oil pump had failed. While I'm sure it happens, can't remember once reading of an oil pump failure on the 964 or 993 board.

Good luck...