993 CEL SAI repair - what to look for
12-10-2017, 11:47 AM
#31
Drifting
I was getting the standard SAI error codes, and shortly after resetting the codes, they came back.
I then attempted to replace the check valve, but I couldn't get it off, so I proceeded to drop the exhaust and roto-root the ports.
My friend came over and was able to remove the check valve. Once off, it was apparent it was the root-cause why the codes were thrown as it was rotted thru.
After putting it all back together, no more codes, and that was 4-years ago.
With all that said, I'm suspecting that simply replacing the bad check valve would have fixed the problem.
I then attempted to replace the check valve, but I couldn't get it off, so I proceeded to drop the exhaust and roto-root the ports.
My friend came over and was able to remove the check valve. Once off, it was apparent it was the root-cause why the codes were thrown as it was rotted thru.
After putting it all back together, no more codes, and that was 4-years ago.
With all that said, I'm suspecting that simply replacing the bad check valve would have fixed the problem.
12-10-2017, 04:56 PM
#32
05-26-2021, 07:11 PM
#33
2nd Gear
Join Date: May 2021
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Clogged SAI port
I am assuming that the car is throwing a P1411 and/or P0410 clogged SAI port CEL.
this means that the secondary o2 sensor is not receiving the amount of O2 that it "wants" as defined by the ECU OBDII system. There are a number of reasons that this can occur.
eventually, the valve guide wear issue WILL cause this, and given time and no having a top end, the ports will get clogged and WILL cause one or both of the 2 codes listed above.
The band aid fix is to try and clean out the ports, however that addresses the effect, not the cause. The cause is (popular belief) that the guides are worn, and oil is blowing by the exhaust valve, clogging the port. Having JUST got my car back from a top end job, and seeing first hand the complexity of the ports, I believe that it is pretty much impossible to completely clean the ports with the so called roto-rooter of bass guitar string method. which is not to say it can't buy you some time.
I would ask the dealer how they addressed the problem, and how they fixed it. Ask open ended questions, not, did you replace the valve guides, and did you use OEM guides or PB aftermarket ones. Let them provide the information, not a means to tell you what you want to hear.
in addition to paperwork, including a warranty, it would be nice if they provided photographs of the rebuild. I doubt a dealer would go through that effort, but the shop that did my top end gave me a thumb drive with photos of the complete rebuild. I didn't really need proof, as I was at the shop twice a week monitoring progress as it was made.
If a dealer is doing the work, they SHOULD fix by doing the valve guide replacement. this by no means guarantees a quality job however, as there are items that need meticulous alignment (cam gears to crank shaft for one) that can cause other issues. ditto with setting the timing, just because they did the right job doesn't mean they did the job right.
this means that the secondary o2 sensor is not receiving the amount of O2 that it "wants" as defined by the ECU OBDII system. There are a number of reasons that this can occur.
eventually, the valve guide wear issue WILL cause this, and given time and no having a top end, the ports will get clogged and WILL cause one or both of the 2 codes listed above.
The band aid fix is to try and clean out the ports, however that addresses the effect, not the cause. The cause is (popular belief) that the guides are worn, and oil is blowing by the exhaust valve, clogging the port. Having JUST got my car back from a top end job, and seeing first hand the complexity of the ports, I believe that it is pretty much impossible to completely clean the ports with the so called roto-rooter of bass guitar string method. which is not to say it can't buy you some time.
I would ask the dealer how they addressed the problem, and how they fixed it. Ask open ended questions, not, did you replace the valve guides, and did you use OEM guides or PB aftermarket ones. Let them provide the information, not a means to tell you what you want to hear.
in addition to paperwork, including a warranty, it would be nice if they provided photographs of the rebuild. I doubt a dealer would go through that effort, but the shop that did my top end gave me a thumb drive with photos of the complete rebuild. I didn't really need proof, as I was at the shop twice a week monitoring progress as it was made.
If a dealer is doing the work, they SHOULD fix by doing the valve guide replacement. this by no means guarantees a quality job however, as there are items that need meticulous alignment (cam gears to crank shaft for one) that can cause other issues. ditto with setting the timing, just because they did the right job doesn't mean they did the job right.
I have the same exact problem with my 97 993. excessive oil consumption and CEL light. I have received quotes as high as $28k to correct the issue from various Porsche dealers in the LA area. I was wondering if anyone knows of a good reliable Porsche shop in southern CA that could address this problem at a reasonable cost. Many thanks.
Last edited by Shahab_S; 05-26-2021 at 07:13 PM.
05-27-2021, 03:58 PM
#35
Yeah. 28k? I'll cover shipping to and from me and I'll fix the ports for... 25k.. lol
09-24-2021, 04:33 PM
#37
Rennlist Member
If you powered up the SAI pump, could you feel the air flow out the exhaust in a correctly operating system? Is the check valve vacuum operated? I don’t remember.