Cleaning SAI Ports...DIY Write Up
10-11-2004, 08:58 PM
#16
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Rob, Great write up! Did you have the CEL that caused you to do this? If so did this fix the CEL problem? How many bottles of Techron did you use?
Thanks
Thanks
10-11-2004, 09:36 PM
#17
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Best thread ever? Really? Wow, to come out of relative obscurity to the head of the pack! Only in America!!!
Joe: No, I didn't have the check engine light. I did this purely as preventative maintenance. Plus, a couple of years ago, I built a shop and put a lift in it, and avoiding a several thousand dollar bill with $200 and 6 hours of work goes along ways toward justifiying the cost of the lift. The check engine light comes on because air is not getting pumped into the exhaust system during warm up, so cleaning out the passages will fix the problem...assuming they were clogged. However, the jury is out on how long this solution will last. As was pointed out on this thread, the longevity of this fix will vary from car to car, depending on how worn the valve guides are. I used one bottle of Techron, but that will vary, depending on how many and how plugged up the passages are. I would say use as much Techron as you need to. Don't skimp on the Techron. The gaskets alone cost over $150, so you want to make sure you get the passages completely clean the first time. Also, the cleaner the passages, the longer it will be before you have to clean them again.
Now I have a question: I want to post the DIY on P-car.com. Does anyone know how to do that or who to get ahold of?
Thanks, Rob.
Joe: No, I didn't have the check engine light. I did this purely as preventative maintenance. Plus, a couple of years ago, I built a shop and put a lift in it, and avoiding a several thousand dollar bill with $200 and 6 hours of work goes along ways toward justifiying the cost of the lift. The check engine light comes on because air is not getting pumped into the exhaust system during warm up, so cleaning out the passages will fix the problem...assuming they were clogged. However, the jury is out on how long this solution will last. As was pointed out on this thread, the longevity of this fix will vary from car to car, depending on how worn the valve guides are. I used one bottle of Techron, but that will vary, depending on how many and how plugged up the passages are. I would say use as much Techron as you need to. Don't skimp on the Techron. The gaskets alone cost over $150, so you want to make sure you get the passages completely clean the first time. Also, the cleaner the passages, the longer it will be before you have to clean them again.
Now I have a question: I want to post the DIY on P-car.com. Does anyone know how to do that or who to get ahold of?
Thanks, Rob.
10-11-2004, 09:49 PM
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Chris,
I've got a number of cone wrenches and I think the problem will be there is not enough wrench left over after it's bent to be able to get any leverage with, and besides if you've used them you know those skinny little things can really dig into your hands. I've got one that's not quite 15/16 but with a file it could be very easily.
Most likely Rob's custom made wrench is the way to go. It works. But it looks like you need to get the bends just right so it will fit properly. I've bent wrenches before and I alway seem to have my hands full trying to get the bends just right. I could do it but I really don't want to.
With the crows foot I think I could grind it down to the proper thickness and then just use maybe a 2" or 4" extension. If necessary I could weld the extension to the base of the crows foot at an angle.
I'm in no rush to do this as it's my intent to perform this job as preventative maintainance.
I've got a number of cone wrenches and I think the problem will be there is not enough wrench left over after it's bent to be able to get any leverage with, and besides if you've used them you know those skinny little things can really dig into your hands. I've got one that's not quite 15/16 but with a file it could be very easily.
Most likely Rob's custom made wrench is the way to go. It works. But it looks like you need to get the bends just right so it will fit properly. I've bent wrenches before and I alway seem to have my hands full trying to get the bends just right. I could do it but I really don't want to.
With the crows foot I think I could grind it down to the proper thickness and then just use maybe a 2" or 4" extension. If necessary I could weld the extension to the base of the crows foot at an angle.
I'm in no rush to do this as it's my intent to perform this job as preventative maintainance.
10-11-2004, 09:54 PM
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10-11-2004, 10:07 PM
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Ron and Chris:
If you'd like, I'll try to find a thin enough wrench in the right size tomorrow. (I used a 15/16 only because I had it lying around.) If the wrench is thin enough and the right size, then all that needs to be done is to bend it in two spots. Since I have the template, I could make the right bends without all the trial and error fitting. If you want to pay for the wrench, the shipping, and a couple dollars for the supplies, I could make the tool for you. I'm not looking to make any money bending wrenches, but I thought this might help. Let me know.....Rob.
If you'd like, I'll try to find a thin enough wrench in the right size tomorrow. (I used a 15/16 only because I had it lying around.) If the wrench is thin enough and the right size, then all that needs to be done is to bend it in two spots. Since I have the template, I could make the right bends without all the trial and error fitting. If you want to pay for the wrench, the shipping, and a couple dollars for the supplies, I could make the tool for you. I'm not looking to make any money bending wrenches, but I thought this might help. Let me know.....Rob.
I bet you sell every one you make. Put me down for one if you decide to start selling these.
10-15-2004, 10:22 AM
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Removal of Check valve
In addition to making the wrench Rob made you may also modify a crowsfoot wrench as follows:
1-Buy a 3/8" drive 1" crowsfoot from Sears, $7.99. It measures 26 mm instead of 25.4 so you only have to file down .6 mm to get 27 mm which is the size you need. I used a file since I wanted to keep the surface from which I was removing material flat and level. I only filed one side.
2-The crowsfoot was way too thick so you have to grind it down. I think it measured about 10 mm thick so you need to remove 3 mm of material which will leave you with the proper thickness of 7 mm. It will fit perfectly and the place where you insert the adapter and extension bar into the crowsfoot lined up just right to clear the side of the valve body and that metal tube.
3-Insert a 3/8" drive to ½" drive adapter into the crowsfoot and attach a 10" extension bar to the adapter. Then use a 15" breaker bar to remove. I initially tried 3/8" drive extension and way too much flex. The valve would not budge.
For anyone that doesn't want to modify a Sears crowsfoot Baum Tools does sell a Stahlwille 27 mm crowsfoot, but it's about $57. plus shipping. I am not 100% certain that the 3/8" drive hole would line up in perfect position to insert an adapter and extension without interfering with the cutoff valve and/or the metal tube. I have the dimensions of the Stahlwille and they are not identical to the modified Sears crowsfoot.
Functioning of check valve and cut off valve
I tested both the cut off valve and the check valve. The cutoff valve was functioning properly with no leakage. The check valve which should only allow air to flow toward the head was not 100%. Air could go through the valve the other way although with much more resistance. I suppose the diaphragm was weak. What the effect of it not functioning at 100%, I don’t know. And this is on a 1997 with 12,200 miles on it.
PCA website regarding Rob's procedure
I would also note that on the PCA website in response to Rob’s writeup of his procedure for cleaning the SAI entitled “cleaning the secondary air injection ports–SUCCESS!” Joel Reiser stated “I have been saying to clean the ports every 15k miles, because we know people are having bad trouble if they do nothing and then get above 30k .” PCA link
I’ve attached a few photos.
In addition to making the wrench Rob made you may also modify a crowsfoot wrench as follows:
1-Buy a 3/8" drive 1" crowsfoot from Sears, $7.99. It measures 26 mm instead of 25.4 so you only have to file down .6 mm to get 27 mm which is the size you need. I used a file since I wanted to keep the surface from which I was removing material flat and level. I only filed one side.
2-The crowsfoot was way too thick so you have to grind it down. I think it measured about 10 mm thick so you need to remove 3 mm of material which will leave you with the proper thickness of 7 mm. It will fit perfectly and the place where you insert the adapter and extension bar into the crowsfoot lined up just right to clear the side of the valve body and that metal tube.
3-Insert a 3/8" drive to ½" drive adapter into the crowsfoot and attach a 10" extension bar to the adapter. Then use a 15" breaker bar to remove. I initially tried 3/8" drive extension and way too much flex. The valve would not budge.
For anyone that doesn't want to modify a Sears crowsfoot Baum Tools does sell a Stahlwille 27 mm crowsfoot, but it's about $57. plus shipping. I am not 100% certain that the 3/8" drive hole would line up in perfect position to insert an adapter and extension without interfering with the cutoff valve and/or the metal tube. I have the dimensions of the Stahlwille and they are not identical to the modified Sears crowsfoot.
Functioning of check valve and cut off valve
I tested both the cut off valve and the check valve. The cutoff valve was functioning properly with no leakage. The check valve which should only allow air to flow toward the head was not 100%. Air could go through the valve the other way although with much more resistance. I suppose the diaphragm was weak. What the effect of it not functioning at 100%, I don’t know. And this is on a 1997 with 12,200 miles on it.
PCA website regarding Rob's procedure
I would also note that on the PCA website in response to Rob’s writeup of his procedure for cleaning the SAI entitled “cleaning the secondary air injection ports–SUCCESS!” Joel Reiser stated “I have been saying to clean the ports every 15k miles, because we know people are having bad trouble if they do nothing and then get above 30k .” PCA link
I’ve attached a few photos.
Last edited by Ron; 12-08-2014 at 09:53 AM.
10-15-2004, 12:17 PM
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Great write up! I know that the 95 cars do not have the CEL issue, but should the OBDI/non-varioram engines be cleaned out in a similar fashion as well, or is the clogging unique to the OBDII/ Vario-ram engines only?
10-15-2004, 02:24 PM
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Below are photos of the rusty check valve from my car. It is a 1997 but it only has 12,200 miles on it. It may be that these valves deteriorate with age as much as with mileage.
Last edited by Ron; 12-08-2014 at 09:52 AM.
10-16-2004, 12:56 AM
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Great write up Rob and Ron!
This whole thing about the check valve going bad so soon and how it might relate to the SAI has me thinking, particularly after seeing the pictures and understanding the pathway for the SAI passageways.
Check my logic. What if the SAI clogging is priamrily mediated by check valves that go bad. Since a defective check valve allows air to flow out of the combustion chamber (recall the SAI outlet is behind the exhaust valve) the SAI passageways clog up in direct proportion to a) The amount of oil being burned in the combustion process and, b) The amount of backflow allowed by the defective check valve.
In other words, the check valve is the only thing preventing oily combustion exhaust gases from being expelled out through the SAI conduits (the wrong way) with every exhaust cycle.
Does this make any sense?
This whole thing about the check valve going bad so soon and how it might relate to the SAI has me thinking, particularly after seeing the pictures and understanding the pathway for the SAI passageways.
Check my logic. What if the SAI clogging is priamrily mediated by check valves that go bad. Since a defective check valve allows air to flow out of the combustion chamber (recall the SAI outlet is behind the exhaust valve) the SAI passageways clog up in direct proportion to a) The amount of oil being burned in the combustion process and, b) The amount of backflow allowed by the defective check valve.
In other words, the check valve is the only thing preventing oily combustion exhaust gases from being expelled out through the SAI conduits (the wrong way) with every exhaust cycle.
Does this make any sense?
10-16-2004, 12:17 PM
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Below is a parts quote from my local dealer. It has the current part numbers that you will need to do what Rob described. The exhaust gaskets are for a Gillet exhaust. My local dealer’s prices are $104. more than they can be purchased from at another Porsche dealer I do business with, although I will have to pay shipping.
Last edited by Ron; 12-08-2014 at 09:52 AM.
10-16-2004, 12:54 PM
#27
"In other words, the check valve is the only thing preventing oily combustion exhaust gases from being expelled out through the SAI conduits (the wrong way) with every exhaust cycle."
The check valve is far "upstream" from the majority of the air passage ports, which doesn't
block the majority of the carbon buildup.
The check valve is far "upstream" from the majority of the air passage ports, which doesn't
block the majority of the carbon buildup.
Last edited by Lorenfb; 10-16-2004 at 01:14 PM.
10-16-2004, 01:09 PM
#28
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Ron:
Be sure to let us know how your ports look and how the cleaning process goes for you. Good luck with it. Also, I think your modified crow's foot with extension and a ratchet is a better way for people to remove the check valve than grinding and bending a wrench like I did. Perhaps you should contact Robin a P-car.com and have your crow's foot wrench added to my DIY article, since your wrench solution would be alot easier for others to duplicate. Take care, Rob.
Be sure to let us know how your ports look and how the cleaning process goes for you. Good luck with it. Also, I think your modified crow's foot with extension and a ratchet is a better way for people to remove the check valve than grinding and bending a wrench like I did. Perhaps you should contact Robin a P-car.com and have your crow's foot wrench added to my DIY article, since your wrench solution would be alot easier for others to duplicate. Take care, Rob.
10-16-2004, 01:14 PM
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Loren,
Correct, the check valve is upstream and when it works correctly, it should prevent gases from flowing throught the SAI conduits. If the exit point for the gases is blocked. then no gases can flow through the conduits, correct? Just like a diode in an electrical circuit.
Correct, the check valve is upstream and when it works correctly, it should prevent gases from flowing throught the SAI conduits. If the exit point for the gases is blocked. then no gases can flow through the conduits, correct? Just like a diode in an electrical circuit.
10-16-2004, 02:12 PM
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Luis,
The cut off valve right above the check valve would stop the flow of any exhaust gas going the other way too, I think. The cut off valve has a diaphrim in it too and when the no vacuum situation exists to the valve then it closes (no air flows thru it). I don't know but I was thinking the cut off valve was only open when the air pump fan was runing. Is that right?
I wonder why there needs to be a check valve too?
The cut off valve right above the check valve would stop the flow of any exhaust gas going the other way too, I think. The cut off valve has a diaphrim in it too and when the no vacuum situation exists to the valve then it closes (no air flows thru it). I don't know but I was thinking the cut off valve was only open when the air pump fan was runing. Is that right?
I wonder why there needs to be a check valve too?