How to avoid buying a car with SAI issues?
03-14-2011, 05:03 PM
#16
Racer
To the OP -
Your list pretty much covers what you need to do.
I wouldn't worry so much about the SAI issues. I certainly wouldn't buy a '95 solely out of fear of SAI problems. Not knocking the '95s, just saying that shouldn't be your primary criteria.
If you search this board you will find a good simple way to clean the SAI ports, it's been referred to as the "bass guitar string" method, but just search SAI and I'm sure it will come up.
Go out and buy the best 993 you can find, cover the items on your list and you'll get a great car. If the CEL comes on down the road, clean out the SAI ports with the wire cable, flush out the system with compressed air and some carb fluid, slap on a new check valve, bolt the exhaust manifolds back on, reset the OBDII, and go enjoy the car until all the OBDII tests cycle through. Then its good to go.
I did mine over 2 years ago and have passed CA smog no problem.
For those who call it a "temporary fix", I'd say to just think of it as a maintenance item. Not yet sure of the interval because I've not heard of anyone who's yet had to do the SAI clean out more than once.
I feel this whole link between SAI and top-end rebuild is akin to killing a fly with a sledgehammer. I agree in some cases it can be necessary (high miles, with evidence of significant oil consumption, etc), but for most SAI clogs, the fix is easy and not very expensive.
Your list pretty much covers what you need to do.
I wouldn't worry so much about the SAI issues. I certainly wouldn't buy a '95 solely out of fear of SAI problems. Not knocking the '95s, just saying that shouldn't be your primary criteria.
If you search this board you will find a good simple way to clean the SAI ports, it's been referred to as the "bass guitar string" method, but just search SAI and I'm sure it will come up.
Go out and buy the best 993 you can find, cover the items on your list and you'll get a great car. If the CEL comes on down the road, clean out the SAI ports with the wire cable, flush out the system with compressed air and some carb fluid, slap on a new check valve, bolt the exhaust manifolds back on, reset the OBDII, and go enjoy the car until all the OBDII tests cycle through. Then its good to go.
I did mine over 2 years ago and have passed CA smog no problem.
For those who call it a "temporary fix", I'd say to just think of it as a maintenance item. Not yet sure of the interval because I've not heard of anyone who's yet had to do the SAI clean out more than once.
I feel this whole link between SAI and top-end rebuild is akin to killing a fly with a sledgehammer. I agree in some cases it can be necessary (high miles, with evidence of significant oil consumption, etc), but for most SAI clogs, the fix is easy and not very expensive.
03-14-2011, 05:18 PM
#17
"Here is what you do, purchase the Durametric Scanner software, install on laptop. When you check out a car, plug in the laptop, then run the SAI pump with the car off, it will push quite a bit of air out the exhaust pipes & make quite a bit of noise."
That's hardly much different than just starting the engine cold, i.e. The air pump
will run by itself. Using that approach, there's no real evaluation of the effectiveness
of the SAI system.
"Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play."
And that's another waste of time, i.e. There's NO real defined standard/measure/procedure
that will assure SAI readiness completion, besides the potential oil leaks from this.
"I had them write in the bill of sale that, if the vehicle wouldn't pass my state's emissions test, they would pay whomever I chose to correct the matter."
Try suing a dealer (many arguments to mitigate the guarantee):
1. The person providing the guarantee had no authority.
2. The guarantee was only at the time of purchase, customer waited 3 months for the test.
3. The guarantee was only for CO/HC/NOx passage.
The defense against the statement is almost endless.
"I wouldn't worry so much about the SAI issues."
Actually, for some it should be an issue of concern, i.e. Since many don't care
nor have the mechanical proclivity to do the cleanout, and the cleanout can take
3-5 hours easily. The typical labor cost will be over $500.
Bottom line: With two equally appealing 993s, the one which will actually pass the SAI
at the PPI should be the one given more consideration.
That's hardly much different than just starting the engine cold, i.e. The air pump
will run by itself. Using that approach, there's no real evaluation of the effectiveness
of the SAI system.
"Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play."
And that's another waste of time, i.e. There's NO real defined standard/measure/procedure
that will assure SAI readiness completion, besides the potential oil leaks from this.
"I had them write in the bill of sale that, if the vehicle wouldn't pass my state's emissions test, they would pay whomever I chose to correct the matter."
Try suing a dealer (many arguments to mitigate the guarantee):
1. The person providing the guarantee had no authority.
2. The guarantee was only at the time of purchase, customer waited 3 months for the test.
3. The guarantee was only for CO/HC/NOx passage.
The defense against the statement is almost endless.
"I wouldn't worry so much about the SAI issues."
Actually, for some it should be an issue of concern, i.e. Since many don't care
nor have the mechanical proclivity to do the cleanout, and the cleanout can take
3-5 hours easily. The typical labor cost will be over $500.
Bottom line: With two equally appealing 993s, the one which will actually pass the SAI
at the PPI should be the one given more consideration.
Last edited by Lorenfb; 03-14-2011 at 05:40 PM.
03-14-2011, 10:26 PM
#18
Rennlist Member
Join Date: Sep 2006
Location: San Diego
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tighter emissions requirements
I haven’t been driving my ’95 coupe too much the last few years and decided to sell it. Well, I had a full price offer, several actually, but when I went to smog the car which one must do to transfer ownership in CA I got a nasty surprise. Sometime since my last test it looks like the state lowered the permissible levels of the products of combustion by around a third. Now the car doesn’t pass the emissions test, 8 PPM too many hydro carbons it seems. A year and a half ago it passed and in that time I did the 90K service and haven’t put more than 1K miles on it. The car uses about a quart every thousand miles best I can figure, but the plugs weren’t fouled when they were changed and its never had a check engine light come on. I'm told too many HC's usually indicate an excessively lean condition, or oil that's not completely consumed by the combustion process. I'll dig into it on Wed. Anybody from a state with more permissive smog requirements want to buy a car?
03-14-2011, 11:17 PM
#19
Racer
"Here is what you do, purchase the Durametric Scanner software, install on laptop. When you check out a car, plug in the laptop, then run the SAI pump with the car off, it will push quite a bit of air out the exhaust pipes & make quite a bit of noise."
That's hardly much different than just starting the engine cold, i.e. The air pump
will run by itself. Using that approach, there's no real evaluation of the effectiveness
of the SAI system.
"Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play."
And that's another waste of time, i.e. There's NO real defined standard/measure/procedure
that will assure SAI readiness completion, besides the potential oil leaks from this.
"I had them write in the bill of sale that, if the vehicle wouldn't pass my state's emissions test, they would pay whomever I chose to correct the matter."
Try suing a dealer (many arguments to mitigate the guarantee):
1. The person providing the guarantee had no authority.
2. The guarantee was only at the time of purchase, customer waited 3 months for the test.
3. The guarantee was only for CO/HC/NOx passage.
The defense against the statement is almost endless.
"I wouldn't worry so much about the SAI issues."
Actually, for some it should be an issue of concern, i.e. Since many don't care
nor have the mechanical proclivity to do the cleanout, and the cleanout can take
3-5 hours easily. The typical labor cost will be over $500.
Bottom line: With two equally appealing 993s, the one which will actually pass the SAI
at the PPI should be the one given more consideration.
That's hardly much different than just starting the engine cold, i.e. The air pump
will run by itself. Using that approach, there's no real evaluation of the effectiveness
of the SAI system.
"Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play."
And that's another waste of time, i.e. There's NO real defined standard/measure/procedure
that will assure SAI readiness completion, besides the potential oil leaks from this.
"I had them write in the bill of sale that, if the vehicle wouldn't pass my state's emissions test, they would pay whomever I chose to correct the matter."
Try suing a dealer (many arguments to mitigate the guarantee):
1. The person providing the guarantee had no authority.
2. The guarantee was only at the time of purchase, customer waited 3 months for the test.
3. The guarantee was only for CO/HC/NOx passage.
The defense against the statement is almost endless.
"I wouldn't worry so much about the SAI issues."
Actually, for some it should be an issue of concern, i.e. Since many don't care
nor have the mechanical proclivity to do the cleanout, and the cleanout can take
3-5 hours easily. The typical labor cost will be over $500.
Bottom line: With two equally appealing 993s, the one which will actually pass the SAI
at the PPI should be the one given more consideration.
All else being equal, of course take the one that has no CEL or SAI issues. But many here were saying buy a '95. I'm just saying, it's not a deal killer -- get the price adjusted accordingly and/or find any 993 w/o the issue, but don't limit your search out of fear of SAI problems.
Last edited by PNogC2S; 03-14-2011 at 11:20 PM. Reason: added one more item
03-15-2011, 12:36 AM
#20
my PPI guy had a nifty device that would measure airflow through the port in the airbox that feeds the smog pump. with the smog pump relay jumped to run it, he could stick the meter in the hole ( had a rubber seal on it) with the engine running and could measure the flow. I think it said 13. this car was local and had had the test before, that I had the records for, and 4 years ago at like 20k miles ago at 15. so my car was seeing less flow and probably was experiencing carbon buildup, but it was still working ok and had never thrown a code for sai. they said that most 993 that come thru that have have sai issues already see about 11-12 on the meter. im hoping that I can get to 90K before dropping the motor and pulling the heads for rebuild. Im at 72K now. I drive about 3-4K a year.
03-15-2011, 02:17 AM
#21
"he could stick the meter in the hole ( had a rubber seal on it) with the engine running and could measure the flow."
Another Mickey Mouse approach!
Bottom line: Do the PPI properly and find a shop/dealer that has and knows
how to use the Porsche testers. Or as some have essentially said: Who cares
about a thorough PPI. Just buy it, and if a problem deal with it later.
Another Mickey Mouse approach!
Bottom line: Do the PPI properly and find a shop/dealer that has and knows
how to use the Porsche testers. Or as some have essentially said: Who cares
about a thorough PPI. Just buy it, and if a problem deal with it later.
03-15-2011, 01:18 PM
#22
Racer
1. Do a PPI -- and everything else on the OP's list
2. If all else is equal buy a car w/o SAI problems
3. Don't be overly afraid of clogged SAI ports, it's an easy fix as long as there aren't other underlying problems.
Lorenfb, If you re-read my posts you will see that all those items were already clearly stated.
03-15-2011, 01:34 PM
#23
Rennlist Member
I haven’t been driving my ’95 coupe too much the last few years and decided to sell it. Well, I had a full price offer, several actually, but when I went to smog the car which one must do to transfer ownership in CA I got a nasty surprise. Sometime since my last test it looks like the state lowered the permissible levels of the products of combustion by around a third. Now the car doesn’t pass the emissions test, 8 PPM too many hydro carbons it seems. A year and a half ago it passed and in that time I did the 90K service and haven’t put more than 1K miles on it. The car uses about a quart every thousand miles best I can figure, but the plugs weren’t fouled when they were changed and its never had a check engine light come on. I'm told too many HC's usually indicate an excessively lean condition, or oil that's not completely consumed by the combustion process. I'll dig into it on Wed. Anybody from a state with more permissive smog requirements want to buy a car?
03-15-2011, 01:54 PM
#24
Nordschleife Master
"Here is what you do, purchase the Durametric Scanner software, install on laptop. When you check out a car, plug in the laptop, then run the SAI pump with the car off, it will push quite a bit of air out the exhaust pipes & make quite a bit of noise."
That's hardly much different than just starting the engine cold, i.e. The air pump
will run by itself. Using that approach, there's no real evaluation of the effectiveness
of the SAI system.
"Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play."
And that's another waste of time, i.e. There's NO real defined standard/measure/procedure
that will assure SAI readiness completion, besides the potential oil leaks from this.
That's hardly much different than just starting the engine cold, i.e. The air pump
will run by itself. Using that approach, there's no real evaluation of the effectiveness
of the SAI system.
"Or you can on the PPI, have them remove the valve covers & check the exhaust valves for play."
And that's another waste of time, i.e. There's NO real defined standard/measure/procedure
that will assure SAI readiness completion, besides the potential oil leaks from this.
If you turn the pump on, & not air comes out of the exhaust, you either have a bad check valve, or clogged SAI passages.
Also most of the time when you get a car PPI'ed you drive it to get done. This will keep the engine warm enough that the SAI will not turn on again. Most people do not leave the car over night for a PPI. Also a lot of people will warm up the car for you before you come & look at it. You can run the scanner & turn on the pump with a hot engine.
Steve W, has said that the best way to tell if you need a top end rebuild is to test the play with the exhaust valves. I'm going to stick with his thoughts on the subject.
03-15-2011, 03:03 PM
#25
I did a write up a while back about cleaning out the SAI ports with a bike brake cable (it is currently under the 993 DIY). It worked perfectly and I have not had an issue since. There is very little chance of success with a guitar string of picture hanging wire. I have also had several people contact me directly regard this fix and all have successfully completed the procedure. I agree that the issue is overblown. While a few of the SAI issues may be a result of leaking valve guides, I believe the real problem is simply a poor design of the SAI air passages and a check valve that has given up the ghost. I also believe that a 993's driven and stored in areas of high humidity are more prone to the problem. The procedure to clean out these ports is not that difficult, and can easily be done by anyone on this forum. Obviously, if you live in California, the car must pass emissions. The emissions test in itself is the easiest and most obvious way to determine if there is an SAI issue. 
03-15-2011, 06:32 PM
#26
Racer
I did a write up a while back about cleaning out the SAI ports with a bike brake cable (it is currently under the 993 DIY). It worked perfectly and I have not had an issue since. There is very little chance of success with a guitar string of picture hanging wire. I have also had several people contact me directly regard this fix and all have successfully completed the procedure. I agree that the issue is overblown. While a few of the SAI issues may be a result of leaking valve guides, I believe the real problem is simply a poor design of the SAI air passages and a check valve that has given up the ghost. I also believe that a 993's driven and stored in areas of high humidity are more prone to the problem. The procedure to clean out these ports is not that difficult, and can easily be done by anyone on this forum. Obviously, if you live in California, the car must pass emissions. The emissions test in itself is the easiest and most obvious way to determine if there is an SAI issue.
03-16-2011, 11:39 AM
#27
"Having the SAI run with the engine OFF is a valid test of the SAI"
Not really! As it STILL doesn't check the O2 sensors and what they measure.
Sounds like many on this thread lack an understanding of OBDII readiness
and how it relates to the problematic issues with the 993.
Besides the SAI readiness, some 993s fail an emissions test because of the
EVAP test too. Again, not testing for that with the Porsche testers at a PPI
is being short-sighted.
"Steve W, has said that the best way to tell if you need a top end rebuild is to test the play with the exhaust valves."
Where's the standard or well defined test procedure for this from a reliable source, e.g. Porsche.
How about a simple one like maybe, oil consumption?
"That may not necessarily be an SAI issue. How old are the cats?"
The cats affect the back O2 sensors and not the front ones which measure the effectiveness of the
air injection.
"If all else is equal buy a car w/o SAI problems"
Seems like we do have a reading comprehension problem here, as that's the point of the thread,
i.e. Determining if a SAI problem exists!!!!!!!!!!!!!!!!
Not really! As it STILL doesn't check the O2 sensors and what they measure.
Sounds like many on this thread lack an understanding of OBDII readiness
and how it relates to the problematic issues with the 993.
Besides the SAI readiness, some 993s fail an emissions test because of the
EVAP test too. Again, not testing for that with the Porsche testers at a PPI
is being short-sighted.
"Steve W, has said that the best way to tell if you need a top end rebuild is to test the play with the exhaust valves."
Where's the standard or well defined test procedure for this from a reliable source, e.g. Porsche.
How about a simple one like maybe, oil consumption?
"That may not necessarily be an SAI issue. How old are the cats?"
The cats affect the back O2 sensors and not the front ones which measure the effectiveness of the
air injection.
"If all else is equal buy a car w/o SAI problems"
Seems like we do have a reading comprehension problem here, as that's the point of the thread,
i.e. Determining if a SAI problem exists!!!!!!!!!!!!!!!!
Last edited by Lorenfb; 03-16-2011 at 11:56 AM.
03-16-2011, 12:49 PM
#28
Nordschleife Master
"Having the SAI run with the engine OFF is a valid test of the SAI"
Not really! As it STILL doesn't check the O2 sensors and what they measure.
Sounds like many on this thread lack an understanding of OBDII readiness
and how it relates to the problematic issues with the 993.
Besides the SAI readiness, some 993s fail an emissions test because of the
EVAP test too. Again, not testing for that with the Porsche testers at a PPI
is being short-sighted.
"Steve W, has said that the best way to tell if you need a top end rebuild is to test the play with the exhaust valves."
Where's the standard or well defined test procedure for this from a reliable source, e.g. Porsche.
How about a simple one like maybe, oil consumption?
Not really! As it STILL doesn't check the O2 sensors and what they measure.
Sounds like many on this thread lack an understanding of OBDII readiness
and how it relates to the problematic issues with the 993.
Besides the SAI readiness, some 993s fail an emissions test because of the
EVAP test too. Again, not testing for that with the Porsche testers at a PPI
is being short-sighted.
"Steve W, has said that the best way to tell if you need a top end rebuild is to test the play with the exhaust valves."
Where's the standard or well defined test procedure for this from a reliable source, e.g. Porsche.
How about a simple one like maybe, oil consumption?
Yes, you can log the O2's voltage with & with out the SAI pump running. But if you turn the pump on, & no air comes out the tail pipes, then the system is NOT working, test done & there is something that needs to be fixed. If the pump is pushing air out the exhaust pimp, then the system is WORKING. Then you can run the engine, read the O2's to see if it's on one bank, or both, or even a partial block.
The point is to test for a PPI, usually you are just seeing if things are good, not doing a bunch of diagnostic work.
I stand, as a EASY & QUICK test, to just RUN THE SAI pump, then feel for the air coming out the exhaust.
Read the Porsche repair manual, there are specs for valve guide wear. Do you really think Porsche would not have a wear spec for this?
It's .8mm lateral movement @ 10mm of lift.
Remember we are talking about a PPI here, not tearing things down, or paying for diagnostic/repair work. No one want to pay $1500 for a PPI.
03-16-2011, 03:00 PM
#29
"Why would we need to test the O2's on a PPI anyway?"
The SAI 'run' test as part of a PPI is NOT testing the O2 sensors.
The O2 sensors are TESTING the secondary air injection.
"If they have failed, they should cause a CEL."
Not necessarily! And what's the definition of failed, e.g. They could be 'slow' & not cause a CEL.
"But if you turn the pump on, & no air comes out the tail pipes, then the system is NOT working, test done & there is something that needs to be fixed. If the pump is pushing air out the exhaust pimp, then the system is WORKING"
A rather naive evaluation. There are cases (what most often happens) that NOT
ENOUGH air is pumped.
"The point is to test for a PPI, usually you are just seeing if things are good, not doing a bunch of diagnostic work"
And what do you think a PPI is if not a diagnosis of the vehicle, e.g. A leak down test.
THAT'S THE PURPOSE OF A PPI!!!!!!!!!!!!!!
"Read the Porsche repair manual, there are specs for valve guide wear."
So! That's the worst case spec,. and NOT necessarily the point at which
SAI problems occur, i.e. Porsche does NOT spec where the limit is for valve
guide wear which will cause SAI failures. They don't even acknowledge the
993 SAI system as an issue!
Most/all competent Porsche shops have testers capable (which the Durametrics is
incapable) of running tests which take only a few minutes and don't affect the typical
PPI cost of $200 - $300. Furthermore, with regard to checking the valve guides,
requesting that as part of a PPI would really impact the PPI cost and many shops
probably would not do the PPI. And who as a 993 owner would allow a shop to R/R
the valve covers for ever potential buyer that wanted a PPI?
The SAI 'run' test as part of a PPI is NOT testing the O2 sensors.
The O2 sensors are TESTING the secondary air injection.
"If they have failed, they should cause a CEL."
Not necessarily! And what's the definition of failed, e.g. They could be 'slow' & not cause a CEL.
"But if you turn the pump on, & no air comes out the tail pipes, then the system is NOT working, test done & there is something that needs to be fixed. If the pump is pushing air out the exhaust pimp, then the system is WORKING"
A rather naive evaluation. There are cases (what most often happens) that NOT
ENOUGH air is pumped.
"The point is to test for a PPI, usually you are just seeing if things are good, not doing a bunch of diagnostic work"
And what do you think a PPI is if not a diagnosis of the vehicle, e.g. A leak down test.
THAT'S THE PURPOSE OF A PPI!!!!!!!!!!!!!!
"Read the Porsche repair manual, there are specs for valve guide wear."
So! That's the worst case spec,. and NOT necessarily the point at which
SAI problems occur, i.e. Porsche does NOT spec where the limit is for valve
guide wear which will cause SAI failures. They don't even acknowledge the
993 SAI system as an issue!
Most/all competent Porsche shops have testers capable (which the Durametrics is
incapable) of running tests which take only a few minutes and don't affect the typical
PPI cost of $200 - $300. Furthermore, with regard to checking the valve guides,
requesting that as part of a PPI would really impact the PPI cost and many shops
probably would not do the PPI. And who as a 993 owner would allow a shop to R/R
the valve covers for ever potential buyer that wanted a PPI?
Last edited by Lorenfb; 03-16-2011 at 03:24 PM.
