Tim Sullivan

I took my 1996 C4S to Hergesheimer's in Lake Forest California just over 3 months ago (5/16/05 to be precise) so they could reset my CEL. When I told them the approach I used to clear the problem with the SAI Laura, who was on the speaker phone and her husband Mark both laughed at me. They both stopped laughing at me when their technician successfully reset my CEL and it stayed off. That was again, about 3 months ago and I would estimate about 4,000 miles ago (63,876 miles when the light first came on and I did the work, 64,022 when I took it into Hergesheimers for the CEL reset and the car is showing about 67,801 miles as of today). The CEL light is still off.

Here is what I did. Removed the air cleaner assembly on the right sideof the engine. Yes it was a bit of a pain but no big deal. One main large hose clamp at the back of the air cleaner to air intake which I was able to reach with a long screw driver, a smaller hose clamp behind the air cleaner housing (for the SAI pump hose) and a couple of bolts securing the air cleaner housing assembly as I recall. The biggest pain was simply getting the damn air cleaner housing in and out of the right side of the engine because it is so tight there in general. Next I was able to remove the actual ACV--Air Check Valve (p/n 993 113 250 03-- about $72 at Newport Beach Porsche if memory serves) by using a deep well 13 MM socket that fit snugly into the top of the Air Check Valve to prevent collapsing the valve when using channel lock pliers to grasp and turn the valve counter clock wise to loosen it. Yeah, go ahead and laugh at me to. No special wrench. No fabricating a special tool to get at the thin base of the ACV. My valve was bad because it clearly was not acting as a one way valve, with air moving in both directions. Bad news.

Next, I installed a 6" length of PVC sprinkler pipe (yep, the same type you fix your lawn sprinklers with available at good 'ole Home Depot) into the female threads of the recepticle for the ACV on top of the engine. Go ahead and laugh some more but the PVC pipe fit perfectly, screwed in by hand and didn't damage the metal threads of the recepticle because the PVC pipe is plastic in nature. I then attached about 3' of 5/8" heater hose to the PVC pipe securing it with a simple hose clamp. Put a funnel on the end of the heater hose and dumped in a 20 oz. container of Chevron Techron Concentrate Fuel System Cleaner (purchased at good 'ole Kragen Auto supply). Let it sit overnight. The next evening I hooked up my 5 HP good 'ole 20 year old Sears air compressor to the end of the heater hose and blasted compressed air into it for about one hour. Removed the air compressor hook up and dumped another 20 oz. container of the Techron into the motor. Let it sit over night. Repeated the compressed air treatment for about another hour. Removed my mickey mouse hose and PVC pipe, installed a new Air Check Valve. Yep, that's right-- used the same 13 mm deep well Craftsman 3/8 drive socket in the Air Check Valve body but made sure not to press it into to far so as not to damge the valve and used the channel lock pliers to secure the valve. I had plenty of leverage and feel very confident that the valve isn't going to loosen. Hooked up the hose from the air pump to the top of the ACV (which should futher secure it from loosening--or moving around if it did come lose). Hooked up the other two hoses and reinstalled the air cleaner housing--again, a real pain because it is so tight there-- but just takes a little patience.

Started the car up and drove it around the block several times to clear out all of the accumulated Techron that was sitting in the engine and boy did it smoke to beat hell! More smoke came out of that motor as the Techron burned off then you can imagine. No it didn't damage my cats because the car runs fine and I haven't had any other CEL indicators. When I took the car to Hergesheimer's for the CEL reset the tech told me he could see an indication that the cats flashed a signal due to all the Techron but again no damage and everything was fine.

Okay, again go ahead an laugh at me to but I spent all of about $100 to fix my CEL problem and didn't have to remove the heat exchangers to do it (Ain't no way I'm going to loosen those rusted nuts on the exhaust manifold studs to remove the heat exchangers as I just know the studs would break off and I don't have a gas torch to heat them up cherry red to begin with!) and didn't have to pay someone to do a $4k top end job. Mickey Mouse? Maybe --but 4,000 miles later and no CEL light and only $100 plus the enjoyment of working on my Porsche ---you be the judge.

ed devinney

Bruce SEA 993

Great write-up. Did you take pictures? There is more than one way to skin the SAI cat!

AOW162435

No lauging here. I applaud when someone takes the time and energy to chart a new route. Sounds like a successful alternative.

Andreas

User 4221

Makes perfect sense to me........ Looks like you built a better mouse trap.

BTW, I used a similar PVC adapter when I did the flush in Feb.

Mark in Baltimore

Great post. Please keep us apprised of further feedback, positive or negative.

TomF

Wow, I am impressed. Thanks for the write-up. Keep us posted.

jimwood

Great write up!

JasonAndreas

Sounds great but where did all the carbon go? The catalytic converters are easy to remove, you might want to take a look and blow them out with compressed air just in case...

Chris M.

I love it.

c

the_buch

Hmmm .... this bears some longer term follow-up to be sure .... does anyone see any downside risk to this?

Dan V

Thanks for the write-up. Think I'll make this a part of my upcoming DIY "major service" PM. As JasonAndreas suggests, it'd be worthwhile to disconnect the cats during the procedure to avert any problems with them. Wonder if my neighbor has a compressor I can borrow...

g_murray

Very innovative!
On the assumption that there wasn't "too much" carbon -- one can assume then that whatever oozed (was blown!) out of the air-ducts towards the upper parts of the cats is being slowly and surely burned off.
For my money, I'd "prefer" carbon deposits to be (sorta) blocking the cats a little -- but being constantly burned away! -- rather than them being up in the SAI area just 'sitting there' and getting harder and harder and harder.

Kudos!

G.

campbesl

Tim,

Good write up of an innovative approach!

I'm going to copy your procedure. Were you using the white PVC pipe? What size was the ID or OD? Do you know what schedule (wall thickness) it is?

GOOD WORK and thanks!!!

Scott

User 4221

I used the black PVC pipe used for sprinkler applications.