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993 CEL SAI repair - what to look for

 
Old 07-29-2016, 01:17 PM
  #16  
2000m2
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How pricey can one expect a top-end rebuild to be?
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Old 07-29-2016, 01:42 PM
  #17  
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Originally Posted by boman993 View Post
This is true. A top end is looming in my future. I'm just waiting for the oil consumption to get to a point where it matters. Right now, it's consuming oil, but very little. Also, in my service records there was never a record of SAI work being done during the life of the car. Once I drilled mine out which was the first time in 16 years, there has been no return of the SAI CEL..is it going to clog again? Probably. But my plan is to be on-top of it ~ change the Check Valve every 15K miles. And if the light comes on before my top-end plan, drill out the ports again.
Agreed, and it is indeed possible, that if you can maintain the ports clean enough through this method, you might be able to avoid a CEL indefinitely.
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Old 07-29-2016, 11:34 PM
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solvents poured in from the top are another method, but if one passage is blocked, the solvent will seek the path of least resistance and flow through an alternate branch, if it is less restrictive.

This is why one would block off the bottom end of the ports, to allow the seafoam or some such chemical to work on the clogged passages.

I would strongly recommend going through the admin post at the top of the 993 forum; Recap of the SAI circuit.
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Old 07-30-2016, 11:30 AM
  #19  
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Originally Posted by 2000m2 View Post
I am looking at a '96 993 that has the CEL SAI issue. It is in a dealers inventory and they are in the process of fixing it. My question is what should I look for when I see the car to make sure the repairs were done correctly? Visually, there is probably not much I can see, but maybe paperwork detailing the work that was done?
The SAI CEL is caused by worn valve guides. The real fix is a top end rebuild. The other "fixes" are band-aides intended to delay the time/expense of a top end rebuild. Which is fine -- just adjust the price accordingly.
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Old 07-30-2016, 12:27 PM
  #20  
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Default Have a Pro Measure as stated earlierin Thread

27,000 + Miles after drilling - No issues - No CEL.
Car had a SAI / CEL History in Ca. with previous owner.

Dealer used Solution to Clean 2x prior to my drilling.
Engine was not "Fully Blocked" - Fortunately so Drilling has worked for me.
At the same time I Changed Resonance Flappe Gasket etc

Now I use the half Litre Approach to Adding Oil - Measuring from Bottom of Dip Stick.
27-28000 Miles since Drillin the Freakin SAI Ports and she pulls hard.

2000 + Miles per Litre Consumption using V Twin 20W-50 @ 112,000 mls
Just Pulled Plugs on Cyl 3, 5 and 6 - All burining Beige in colour.

It will be Years b 4 I consider a Rebuild Necessary although I do have a 3.8 itch.
Engine Production Consistency may be the unknown factor here.
Have a Pro Measure for peace of mind
:>)
Happy - Goin for a cruise!
Cheers
TJ

Last edited by TJ993; 07-30-2016 at 12:35 PM. Reason: addl info
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Old 07-30-2016, 12:40 PM
  #21  
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Originally Posted by Kika View Post

this means that the secondary o2 sensor is not receiving the amount of O2 that it "wants" as defined by the ECU OBDII system.
pretty sure thats the primary 02 that you are referencing, not the secondary.
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Old 07-30-2016, 10:09 PM
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Originally Posted by Quadcammer View Post
pretty sure thats the primary 02 that you are referencing, not the secondary.
Quad,
Is the primary O2, the precat?
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Old 08-01-2016, 12:52 AM
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Originally Posted by Quadcammer View Post
pretty sure thats the primary 02 that you are referencing, not the secondary.
I meant the 1411 and 0410 are the Secondary Air Injection CELs, and those are turned on because the O2 sensors are not getting enough O2, due to clogged port. Yes, when he blower turns one, and blows air into the system the O2 sensor before the cat, is supposed to read a certain level.
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Old 08-01-2016, 08:54 AM
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Originally Posted by nine9six View Post
Quad,
Is the primary O2, the precat?
yes.
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Old 08-01-2016, 07:13 PM
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I think that the SAI valve needs to be replaced often. The valve is a check valve that prevents exhaust gases from flowing the wrong direction. Last I replaced mine after 30,000 miles, the valve flowed both directions. I think that back flow is what may lead to clogging.
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Old 08-03-2016, 01:23 AM
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Originally Posted by vincer77 View Post
I think that the SAI valve needs to be replaced often. The valve is a check valve that prevents exhaust gases from flowing the wrong direction. Last I replaced mine after 30,000 miles, the valve flowed both directions. I think that back flow is what may lead to clogging.
Vince,
I agree wholeheartedly that the SAI check valve is one of the contributing causes to clogged SAI ports.

Also, when the engine oil is overfilled, it gets sucked into the SAI system... Add a non-functioning check valve and hot exhaust gasses and the oil bake into the SAI passages, begins...

I think Andy, pulled and replaced his, and recommended no longer than 15k mi. per valve.

Last edited by nine9six; 12-09-2017 at 11:28 PM.
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Old 09-28-2016, 01:15 AM
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So should we be replacing these Check Valves as a precaution every so often? I'm at about 50K miles with no CEL but better safe than sorry if this is the case.
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Old 09-28-2016, 12:54 PM
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Originally Posted by Shtootgart View Post
So should we be replacing these Check Valves as a precaution every so often? I'm at about 50K miles with no CEL but better safe than sorry if this is the case.
Yes. I'd suggest every 10 to 15k miles.
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Old 12-09-2017, 07:15 PM
  #29  
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Default Seafoam vs SAI OBD II 993

Originally Posted by E30M3 View Post
Has anyone ever successfully unclogged the SAI ports by using Seafoam?
Yes, i tried it and ran the car, the CEL turned off.
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Old 12-09-2017, 11:45 PM
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Originally Posted by lwky993 View Post
Yes, i tried it and ran the car, the CEL turned off.
I do not see how Seafoam can possibly clear clogged SAI ports.

Which Seafoam product did you use, and how did you use it?
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