Tech StuffBy Roger WalkerTechnical ChairWhile looking for something to write aboutfor this month’s article, I came across a couple<strong>of</strong> good DIY write-ups on Robin Sun’s website (http://www.p-car.com/). The 993 is verygood at adjusting for variances in idle situationssuch as different flywheels or exhaustsystems. For example, the 964 has a veryhard time adjusting to having a lightweightflywheel installed and will tend to die at idle,whereas the 993 has a more sophisticatedidle control system and will adapt. About ayear ago, I installed some <strong>of</strong> Robin’s modifiedmufflers on my ‘96 Carrera, and for the first100 miles the idle varied, and even stalled theengine a couple <strong>of</strong> times, but after about twohours, the system learned the new variablesand settled down to a smooth idle again.If you have a 993 and have been having aninconsistent idle, then the following mightbe helpful and will give you some familiaritywith your engine. I’ve done a little editingfor brevity’s sake. Also, there is a differencein intake systems on a ‘95 versus ‘96-’98 3.6lmotor, so the pictures shown below might bea little different from what you see in your car,but the location <strong>of</strong> this valve is the same.Idle Stabilizer Valve (ISV) CleanoutContributed by: Robert HenriksenDegree <strong>of</strong> difficulty: 2-3 out <strong>of</strong> 10, 10 beingthe most difficult.Tools you’ll need:• #2 Phillips screwdrivers: regular and long• a 7mm box wrench or open-end wrench,and/or a 7mm socket, ratchet, and 3”-6”extension• spray can <strong>of</strong> carburetor or brake cleaner(basically a really volatile spray solvent)• paper towels, cleaner, maybe some cottonswabs and silicone or WD-40 sprayYou can see the silver canister sittingon the very top <strong>of</strong> the intake manifold, justbarely fitting below the rear window. Loosenthe rearmost hose clamp and wiggle the aluminumpipe out <strong>of</strong> the way, as in the photo.Just undo three hose clamps and wrestle itout <strong>of</strong> its home. Once removed from the top<strong>of</strong> the motor, there is no further disassembly<strong>of</strong> the ISV needed or recommended. [Toremove the electrical connector, push in gentlyon the metal wire/clip on the connectoritself.]The rearmost hose clamp has been loosenedand the aluminum pipe wiggled out <strong>of</strong> the way.There are two things that make removingthe ISV a pain: First, the factory workerwho tightened the hose clamps originallydid it with the engine outside <strong>of</strong> the car. Hedidn’t have to worry about being able to get ascrewdriver on them later when the motor isin the car. Naturally, the screws are pointing<strong>of</strong>f in impossible angles. That’s why I had touse a 7mm wrench on the back hose clamp,there was no way to get a screwdriver on it.[Robin did it by using a flexible shaft screwdriver.]The other problem is just that the circularrubber gasket surrounding the ISV is probablyold and dirty, making it hard to slide thecylinder out. One thing I did which helpedwas clamp down a pair <strong>of</strong> channel lock plierson the #2 intake runner, right next to the ISV.That gave me a fulcrum to lever a big screwdriveragainst the left end <strong>of</strong> the cylinder toget it started sliding out to the right. [I amnot crazy about this suggestion; use a rag toprevent scratching your manifold if you dothis. Robin sprayed a little WD-40 aroundthat area to loosen it.]Here’s what’s left once you wrestle the ISVout …… and the ISV alone.I strongly recommend wearing goggleswhen using brake cleaner! It’s either thator having a garden hose or bathtub handyfor massive amounts <strong>of</strong> flushing your eyeswhen the inevitable happens and you get astrong back-blast <strong>of</strong> that stuff directly intoyour eyeball. Ask me how I know. That said,peek into the entrance and exit pipes, andtwist the ISV around. There probably won’tbe much movement inside yet.Eventually it will look like this.Once you’ve blasted it well with thecleaner, shake as much <strong>of</strong> the dirty cleanerout as possible, and mop up with papertowels. I found a couple <strong>of</strong> Q-Tips helpedme scrub <strong>of</strong>f some <strong>of</strong> the dirt that was onthe surface <strong>of</strong> the rotating assembly inside.Give the remaining solvent in the cylindertime to dry out; it takes just a few minutes.I guess you could hasten that process withan air hose and blow tip, but I’m not in thatmuch <strong>of</strong> a rush.Note the gunky inner surface <strong>of</strong> the rubber ringgasket.One other thing I did to make my lifeeasy was to clean up the dirt with SimpleGreen, paper towels, and a fingernail. Ithen soaked the interior <strong>of</strong> the gasket withArmor All. I don’t use that silicone-basedstuff anymore on my interior, but figured itwould make a good lubricant to slide thecylinder back into its home, and it workedout okay.One <strong>of</strong> the more satisfying things aboutdoing this job yourself is that you can reattachthe hose clamps such that you can actuallyget to them easily with a screwdriver in16 The Drifter
the future! Having a #2 Phillips screwdriverwith about a 10” shaft makes this a lot easieron your knuckles.Reinstall the valve in reverse order, andplug in your electrical connector. Onceeverything’s back together and you’vestarted up the engine, your idle may take afew minutes to self adjust, so a short drivemight be in order. I’ve also sometimes disconnectedthe battery for a couple <strong>of</strong> hoursor overnight to clear the engine computer.However, before disconnecting the battery,be sure you have the security code to resetyour radio. The procedure is not hard (aslong as you have the right code!); consultyour owner’s manual for instructions.Our Mission: To provide tasteful and unique design while meeting orexceeding our customer’s expectations.Custom or restoration for fine cars, classicStreet Rods, and boatsCabriolet TopsSeatsDoor PanelsCarpetsTonneau CoversCar CoversWe look forward to the opportunity to serve you!Bob Rinker - Owner & Master CraftsmanErik Carlson - Apprentice Craftsman11300-G Sunrise Gold Circle, Rancho Cordova, CA 95742(916) 858-1808www.karmakreations.comMaster Craftsmanship with over 25 YearsExperience10 Year <strong>Porsche</strong> <strong>Club</strong> Member andSponsor<strong>Porsche</strong> owner (911, Classic 914)Visa and MasterCard Accepted“If you can dream it, we can build it!” — BobThe Drifter17
Change language