993 VarioRam Spark Plug Wire R & R DIY

Contributed by:

Robert Henriksen

Update added July, 2004

Information contributed by Bruce Hollett

Per Bruce:I have done plug wires a few times now on 993's, and I always buy the wires made by STI. They are a premium wire, and best of all, they come with all of the brackets and grommets pre-installed. It's a huge timesaver since you don't have to transfer the brackets, grommets, etc. They look exactly like the factory wires. Also, I don't usually remove the "gizmo". Rather I just snake the wires out around behind it.

Thanks again,


Degree of difficulty: 7
(In a scale of 1-10, 10 being the most difficult)

Tools you'll need:

Preface: the engine cylinders are numbered starting from the driver's side, rear of the car, 1-2-3 up the left (driver's side) bank, from rear bumper towards the front, and then 4-5-6 are right (passenger's) side, again rear towards the front. The factory has a separate part number for each plug wire for good reason - each one is a different length. I used the same labeling scheme for the existing wires as the factory part numbers: 01 - 06 for the intake side (top) wires, and 11 - 16 for the exhaust (bottom) wires. You'll want to label *both* the existing wires, and the new ones immediately upon removing each one out of its plastic bag.

Preface #2: This whole procedure will be a lot easier on your back if you jack the rear (and only the rear) of the car up, even when you're only working on the top of the motor.

Remove the entire air intake box on the right side - not just the cover, but the intake air filter & the housing it lives in. The cover is only retained by the two snaps on the front; getting the rest of the airbox housing off is easy once you know the trick. The back of the airbox has a couple of 'hook' shapes cast into the back, around the opening that the air flow sensor (AFS) pokes through. The AFS has corresponding projections that'll rotate into those hooks -- basically, a bayonet-style connection. Since the airbox doesn't have room to rotate, you have to loosen the AFS' hose clamp on its inboard side so that *it* can do the rotating to disengage that bayonet connection.

(From Mike Juzenas:)
- Undo the top bolt on the front of the air box
- Squeeze your hand over the top of the manifold, between the ISV and the airbox, and unscrew/unplug the wires plugged into the air flow sensor
- Loosen the clamp on the inboard side of the air sensor. This takes a very long Phillips screwdriver (10" shaft or longer) and good eyesight but you should be able to see it over the top of the Varioram body. Thankfully, this is one hose clamp where the screw is oriented in a usable direction. A flashlight is a big help here. Loosen it just enough to rotate the air mass sensor
- Squeeze your hand back in there between the top of the manifold and the sound insulation, grab the air sensor and rotate the top towards the front of the car. You need to rotate it until the air box comes loose.
There is a ~1.5" diameter black rubber hose that connects to the back side of the airbox, between the #4 and #5 intake runners; disconnect it at * both* ends & remove it.

Remove all the black plastic HVAC plumbing on the left side of the engine - it's only about four bolts & a hose clamp or two. You do need to remove the circular black heater fan & connected ductwork - it's only secured by two bolts on the left side, easily accessible. You'll have tons o' room on both sides of the intake manifold when  you get all this stuff out of the way. As an aside, this is a great time to replace the shocks that hold up the engine lid. I recommend using needle nose visegrips to remove & replace the clips that hold the pins in; less chance of losing the clips by accident.

    There is a small black gizmo clipped to a cross-brace between the intake runners for cylinders 1 & 2, with an electrical plug on top & some vacuum lines below. Unplug the wires from the top, slide the assembly up & off the cross-brace, and tuck it out of the way. I didn't disconnect any of the vacuum lines from it. It's hard to see in the picture below, but you can see the location of my hand; also note the labeling of the plug wires. This is before I noticed them losing adhesion & falling off; I went back & popped a staple through each one to make sure they didn't come off again. The '1A' label is attached to the wires that came off the assembly I'm removing here. Why '1A'? Didn't know what else to call it... gizmo?

    Okay, to actually remove the old wires your hands & wrists can't be too big, and it helps if you don't have any claustrophobic tendencies :-) There are two clamps, four screws total, securing the wires to the back of the fan shroud. Snake your left hand between the #1 & 2 intake runners, then hand yourself the stubby phillips screwdriver. There will be enough room to use it on this side, so enjoy it while you can. Thankfully, the screws aren't super tight so you don't need a lot of leverage/muscle. I call this the Vario-Reach:

    Extricate yourself & massage your hand for a bit.

    Now, snake your right hand between the #5 & 6 intake runners on the right side of the engine. Hand yourself the ratcheting screwdriver, or the cobbled-together masterpiece described above. The only room you really have for your right hand is to hold the tool in place on the screw. I would orient the tool pointing the handle towards myself, and poke my left fingers through the gap between fan shroud & intake to rotate the screwdriver 90 degrees. Patience is the key here; just keep repeating to yourself, "I don't have to remove the intake, I don't have to remove the intake, life is good..."
    A central idea here is that because all three intake plug wires are connected together with clamps to keep them organized, (and ditto for the three exhaust plug wires), you need to remove all three wires from the engine as a set, *clamps intake*, then transfer the new wires into the same set of clamps, CAREFULLY maintaining the spacing between each connector. Below is the old wire/connector set for the right-side exhaust plugs. There are four clamps keeping the wires parallel, plus a soft rubber guide for where the wires pass through the engine shroud. Note that the old wires are labeled; the three new wires are still in bags & haven't been labeled yet.

    Now the new wires are labeled, and the four clamps transferred onto them. Note that the distance between clamps is NOT the same for each wire! They are different between some of the clamps because of the curved path that the harness takes around the back of the fan shroud. You want to really take your time with this, and get the clamps spaced exactly right, wire by wire. Fishing the assembly in & out of the engine is not something you want to do over & over again till you get the spacing just right. The soft rubber guide has to be cut off the old wires & slid onto the new ones - a nice new, sharp single edge razor blade goes through it 'like buddah'

    Additional note added March 28,2003  from chris byles

    Regarding the re-installation of the large rubber grommet that is on the bottom wires which does NOT have to be cut to be installed on the new wires. You can actually unscrew the plug boots from the plug wires. When this is done you can slide the wires through the grommet, then
    reinstall the wires. The allows for a cleaner install and keeps the integrity of grommet

    That's the highlights. You get extra points for not having any pieces left over after reassembly.

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