Sooty tailpipe - engine analysis
#1
Racer
Thread Starter
Join Date: Dec 2004
Location: Cotswolds UK
Posts: 368
Likes: 0
Received 0 Likes
on
0 Posts
Sooty tailpipe - engine analysis
Here's an unpdate for those of you who have been following the saga of me trying to get to the bottom of one sided sooty tailpipe on my 10,000 mile 997s. The engine was in tolerance for compression and leakdown and passed the full diagnostics but, after speaking to Porsche, the dealer has removed the engine and has started to tear it down. So far, they have found oil in the exhaust port of number 4 cylinder and are going on to check the bore tomorrow. Number 4 is on the side that supplies the sooted up exhaust so looks like we may have an explanation. Not sure what Porsche intend to do about it yet but both dealer and Porsche have been brilliant - something I hope will continue.
Will let you know the final outcome.
PS taking the opportunity to fit a PSE and new clutch.
Will let you know the final outcome.
PS taking the opportunity to fit a PSE and new clutch.
#2
Instructor
Join Date: Sep 2005
Location: Midlands, UK
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
I have been following this saga with interest. I have suggested a couple of times that both a wet and a dry compression test be carried out. A wet test requires a squirt of oil through the spark plug hole and reduces leakage past the rings. A low dry pressure which increases when wet indicates a problem with the piston rings/bore but a low dry pressure that fails to increase when wet probably indicates a valve seating problem.
#4
Guest
Posts: n/a
Originally Posted by Drmark
Here's an unpdate for those of you who have been following the saga of me trying to get to the bottom of one sided sooty tailpipe on my 10,000 mile 997s. The engine was in tolerance for compression and leakdown and passed the full diagnostics but, after speaking to Porsche, the dealer has removed the engine and has started to tear it down. So far, they have found oil in the exhaust port of number 4 cylinder and are going on to check the bore tomorrow. Number 4 is on the side that supplies the sooted up exhaust so looks like we may have an explanation. Not sure what Porsche intend to do about it yet but both dealer and Porsche have been brilliant - something I hope will continue.
Will let you know the final outcome.
PS taking the opportunity to fit a PSE and new clutch.
Will let you know the final outcome.
PS taking the opportunity to fit a PSE and new clutch.
#5
Originally Posted by snarf
I have been following this saga with interest. I have suggested a couple of times that both a wet and a dry compression test be carried out. A wet test requires a squirt of oil through the spark plug hole and reduces leakage past the rings. A low dry pressure which increases when wet indicates a problem with the piston rings/bore but a low dry pressure that fails to increase when wet probably indicates a valve seating problem.
his compression wasnt low to begin with a a wet test wouldnt have made much diffrence. then there is always the problem with wet compression tests on a flat motor..................
#6
Rennlist Member
Thanks for keeping us posted...I know there have been a number of drivers on various forums (fora?) that have reported the same uni-soot problem.
Nice job on adding the PSE....you deserve a treat after this saga!
Nice job on adding the PSE....you deserve a treat after this saga!
#7
Originally Posted by Drmark
Here's an unpdate for those of you who have been following the saga of me trying to get to the bottom of one sided sooty tailpipe on my 10,000 mile 997s. The engine was in tolerance for compression and leakdown and passed the full diagnostics but, after speaking to Porsche, the dealer has removed the engine and has started to tear it down. So far, they have found oil in the exhaust port of number 4 cylinder and are going on to check the bore tomorrow. Number 4 is on the side that supplies the sooted up exhaust so looks like we may have an explanation. Not sure what Porsche intend to do about it yet but both dealer and Porsche have been brilliant - something I hope will continue.
Will let you know the final outcome.
PS taking the opportunity to fit a PSE and new clutch.
Will let you know the final outcome.
PS taking the opportunity to fit a PSE and new clutch.
Trending Topics
#8
Racer
Thread Starter
Join Date: Dec 2004
Location: Cotswolds UK
Posts: 368
Likes: 0
Received 0 Likes
on
0 Posts
I was using about 750mls per 1000 miles but suspect it was being burnt in the right bank only - and probably cylinder 4 from what we know so far. If anything it was lessening as the engine bedded in.
The new clutch is a precautionary change as I bought the car second hand - if the existing one looks great I'll leave it in, but it's not a lot of money to pop a new one in while the engine is out. And if I end up with a new engine under warranty it could come with a new clutch (they often do evidently according to my dealer). Porsche Bristol sold me the car and are really going the extra mile - but so they should given how much a 2 year old 997 costs over here!
The new clutch is a precautionary change as I bought the car second hand - if the existing one looks great I'll leave it in, but it's not a lot of money to pop a new one in while the engine is out. And if I end up with a new engine under warranty it could come with a new clutch (they often do evidently according to my dealer). Porsche Bristol sold me the car and are really going the extra mile - but so they should given how much a 2 year old 997 costs over here!
#10
Originally Posted by Drmark
I was using about 750mls per 1000 miles but suspect it was being burnt in the right bank only - and probably cylinder 4 from what we know so far. If anything it was lessening as the engine bedded in.
The new clutch is a precautionary change as I bought the car second hand - if the existing one looks great I'll leave it in, but it's not a lot of money to pop a new one in while the engine is out. And if I end up with a new engine under warranty it could come with a new clutch (they often do evidently according to my dealer). Porsche Bristol sold me the car and are really going the extra mile - but so they should given how much a 2 year old 997 costs over here!
The new clutch is a precautionary change as I bought the car second hand - if the existing one looks great I'll leave it in, but it's not a lot of money to pop a new one in while the engine is out. And if I end up with a new engine under warranty it could come with a new clutch (they often do evidently according to my dealer). Porsche Bristol sold me the car and are really going the extra mile - but so they should given how much a 2 year old 997 costs over here!
#11
Three Wheelin'
Originally Posted by Porky
Mark
Glad that its getting sorted but meanwhile does the dealer supply you with a car to drive around while yours in the workshop?
Glad that its getting sorted but meanwhile does the dealer supply you with a car to drive around while yours in the workshop?
#12
Originally Posted by Porky
Mark
Glad that its getting sorted but meanwhile does the dealer supply you with a car to drive around while yours in the workshop?
Glad that its getting sorted but meanwhile does the dealer supply you with a car to drive around while yours in the workshop?
I'm thinking the same thing here. How long has your car been in the shop for and what do they have you driving? In some states extended time in the shop qualifies for the lemon law. I'm glad the dealer and Porsche is trying to get to the bottom of this for you, but you own a $100k car, you should be driving it, not watching it get disassembled.
I'd settle for driving nothing less than an equivalent car while it's in the shop. If you had a "problem" with cash flow in a given month you think Porsche would be ok with taking a "lesser payment"? You shouldn't be ok driving a lesser car.
#14
Instructor
Join Date: Sep 2005
Location: Midlands, UK
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 99firehawk
his compression wasnt low to begin with a a wet test wouldnt have made much diffrence. then there is always the problem with wet compression tests on a flat motor..................
#15
Originally Posted by snarf
Yes a good point, and on reflection oil in the exhaust port would suggest a leak via the valve stem, something a compression test would not pick up.