Secondary Air Injection Veterans needed

[Gelbster]

My most often quoted phrase is "While you are in there".
My preference is replace/test everything ' while you are in there' because I am very short of time and sadly lacking in diagnostic skills.
Of the few parts i did not replace with new when I rebuilt the engine - those are the ones I am now suspicious of. Grrrr!
Worse, it is highly likely I'll do all the disassembly work to the inlet manifold & maybe alternator and find the SAI parts to be perfectly functional !
Throwing parts at a problem instead of diagnosis is ***. But in this case the parts are cheap and why refit parts that although functional may be close to the end of their life?
Pity about the R&R time though.
Please find links to the generic parts that have been used by others. No need to pay the P-tax if you don't want to.
Hope this helps-must get back to work.

[ddruker]

I just finished refreshing the SAI system on my 2001 Boxster S Tiptronic. I was seeing about once a month OBD code P0410 accompanied by the Check Engine Light, associated with the car sitting for a while, so I assumed I had a slow leak somewhere that was triggering the code after the car sat for a week or more and the vacuum slowly escaped. The code does not occur when I am driving the box more frequently. Like the prior poster, I took the "replace everything" approach since the parts are only about $200 and this project requires a lot of painful/annoying labor.

I replaced all of the plastic lines and rubber fittings with 4mm inside diameter / 9mm outside diameter silicone vacuum hose, 3/16" or 5mm outside diameter brass barbed fittings (one 4-way, one 3-way Y shaped, and a couple of barbed connectors) and about 20 8mm hose clamps, all purchased from Amazon for about $30.00. I used about 5 feet of the silicone hose, I would buy a 10-foot section so you have extra for mistakes.

I also replaced the vacuum accumulator tank $21.00 (993-110-140-03), two of the vacuum switches $17.00 each (7PP-906-270), the one-way check valve $15.00 (964-110-950-02) and the air injection valve $99.00 (997-113-249-90). I would have replaced all three vacuum switches but I only ordered two of them as I am dumb sometimes.

Probably because I have the S with automatic transmission, the following things were different than I've seen discussed in most of the rest of the SAI Threads.

- I had 3 vacuum switches. One controlling the air injection valve, one heading down to the automatic transmission, and one controlling the air intake resonator flap.

- I had a four-way junction attached to the vacuum accumulator, and also a three-way junction attached to the check valve.

- The check valve was plugged directly into the right-hand rubber boot on the air intake resonator.

I accessed everything from above and from the passenger compartment, after removing the alternator. It was VERY tight working underneath the intake manifold - in particular reaching the bolts on the underside of the air injection valve was challenging. A very small ratchet with 10mm socket plus a 10mm wrench did the trick, and I had to remove my gloves and fiddle by hand to get the bolts in from underneath. I also had to remove the intake manifold resonator tube as the lines run underneath it.

The existing air injection valve did not have a gasket installed. I installed a gasket with the new one - the metal gasket is included with the new injection valve.

The system would have been impossible to repair using the existing tubing - after 20 years, the rubber connectors were effectively welded to the hard plastic tubing and to the other various valves and switches, and the hard plastic tubing was super brittle. I broke most of it trying to disconnect the old system, and I was being pretty careful.

The whole project end to end took about six hours, and it was not very fun.

[Gelbster]

Thanks for the description.
With the benefit of hindsight , do you think it would have been better to have removed the inlet manifold ? I ask because that is the method proposed in some of the links/videos.
The need to source all the hoses and barbed brass connectors can take a while so to others who are contemplating this job- be prepared for a hiatus.
Once you've done the job, be ready for another delay while the electronics take their sweet time/miles before the Fault Codes all disappear.
So do this job waaay ahead of your Smog Test.

Originally Posted by ddruker

I just finished refreshing the SAI system on my 2001 Boxster S Tiptronic. I was seeing about once a month OBD code P0410 accompanied by the Check Engine Light, associated with the car sitting for a while, so I assumed I had a slow leak somewhere that was triggering the code after the car sat for a week or more and the vacuum slowly escaped. The code does not occur when I am driving the box more frequently. Like the prior poster, I took the "replace everything" approach since the parts are only about $200 and this project requires a lot of painful/annoying labor.

I replaced all of the plastic lines and rubber fittings with 4mm inside diameter / 9mm outside diameter silicone vacuum hose, 3/16" or 5mm outside diameter brass barbed fittings (one 4-way, one 3-way Y shaped, and a couple of barbed connectors) and about 20 8mm hose clamps, all purchased from Amazon for about $30.00. I used about 5 feet of the silicone hose, I would buy a 10-foot section so you have extra for mistakes.

I also replaced the vacuum accumulator tank $21.00 (993-110-140-03), two of the vacuum switches $17.00 each (7PP-906-270), the one-way check valve $15.00 (964-110-950-02) and the air injection valve $99.00 (997-113-249-90). I would have replaced all three vacuum switches but I only ordered two of them as I am dumb sometimes.

Probably because I have the S with automatic transmission, the following things were different than I've seen discussed in most of the rest of the SAI Threads.

- I had 3 vacuum switches. One controlling the air injection valve, one heading down to the automatic transmission, and one controlling the air intake resonator flap.

- I had a four-way junction attached to the vacuum accumulator, and also a three-way junction attached to the check valve.

- The check valve was plugged directly into the right-hand rubber boot on the air intake resonator.

I accessed everything from above and from the passenger compartment, after removing the alternator. It was VERY tight working underneath the intake manifold - in particular reaching the bolts on the underside of the air injection valve was challenging. A very small ratchet with 10mm socket plus a 10mm wrench did the trick, and I had to remove my gloves and fiddle by hand to get the bolts in from underneath. I also had to remove the intake manifold resonator tube as the lines run underneath it.

The existing air injection valve did not have a gasket installed. I installed a gasket with the new one - the metal gasket is included with the new injection valve.

The system would have been impossible to repair using the existing tubing - after 20 years, the rubber connectors were effectively welded to the hard plastic tubing and to the other various valves and switches, and the hard plastic tubing was super brittle. I broke most of it trying to disconnect the old system, and I was being pretty careful.

The whole project end to end took about six hours, and it was not very fun.

[ddruker]

Originally Posted by Gelbster

Thanks for the description.
With the benefit of hindsight , do you think it would have been better to have removed the inlet manifold ? I ask because that is the method proposed in some of the links/videos.


The need to source all the hoses and barbed brass connectors can take a while so to others who are contemplating this job- be prepared for a hiatus.
Once you've done the job, be ready for another delay while the electronics take their sweet time/miles before the Fault Codes all disappear.
So do this job waaay ahead of your Smog Test.

The parts from Amazon all showed up within a couple of days. The exact parts I purchased from Amazon were:

• uxcell 6mm or 1/4 inches ID Brass Barb Splicer Fitting 4 Ways Brass Cross Barb Fitting Air Gas Water Fuel,2pcs
• Legines Brass Hose Barb Y-shaped Tee, 3/16" T Union, Barbed Tube Pipe Fitting, Coupler Connector Adapter 2 pcs
• LTWFITTING Brass Barb Splicer Mender 3/16" Hose ID Fitting Air Water Fuel Boat( Pack of 10 )
• uxcell Steel Band Clamp 8mm for Fuel Line Silicone Hose Tube Spring Clips Clamp Silver Manganese Steel 20Pcs
• High Performance Silicone Vacuum Tubing Hose, ID 0.16" (4mm), OD 0.35" (9mm), 10 Feet per roll (3 Meter), Black 60 psi Maximum Pressure

It's very hard for me to answer your hindsight question. I went the alternator route because I had already replaced the air oil separator on my box, which required me to remove all of the hoses connected to the AOS plus the throttle body and the cross-tube - so I felt comfortable taking those components off again. Removing the alternator was easy - and I didn't come close to breaking anything during that part of the job.



I was worried about removing the intake manifold and potentially breaking more stuff only because I have never had the manifold off before - but doing so would definitely make this project easier, by giving much better access to the vacuum reservoir, the switch and the air injection valve and all the plumbing that sit underneath it.



I hope this helps. I guess the net is that if you are comfortable removing the intake manifold, and you can see how to get access to all of the bolts holding it onto the engine block from above, then that would be easier. If you have to take the alternator out to get the manifold off, then removing the manifold is a redundant step.