Bad Spark Plug wires?? How do I find out?

[944S Boyeee]

I have had some dropping idles whenever it is damp out. I figure it is bad plugs or wires. I noticed the other day that one of my wires was touching the inside of the hood and there is a lil' black burn spot where the wire touched and there is red paint on the wire itself. Is this a sure fire (pardon the pun) way of knowing my wires are bad? Does this indicate jumping sparks? How can I test my wires to see if I'm losing spark?

I recently bought the plugs, but really don't know how to change them. I'd like to replace the plugs before I put new wires on (which I will end up doing anyways), just incase my idle drop is plug related. How do I change my plugs? It is a simple procedure I'm sure - but it is not listed on the Porsche Garage and I don't want to start pulling this out and that out and do it wrong my first time.

[FlyinAh944]

If you still have the tool kit that originally came with your car there is a spark plug wrench, find it, you will need it. If you do not have the kit most autoparts stores stock sprk plug wrenchs, ie autozone ext.

Follow your spark plug wires towards the engine. Unplug one wire, you should see an exposed spark plug head. Unscrew this with the wrench. When it is out place your new spark plug in the wrench and screw the new plug into place. Only screw it hand tight however. Reconnect your spark plug wire. Repeat this procedure one at a time for all 4 plugs.

[Lawrence Coppari]

To check wires you could run engine in the dark and look for coronas. Also you could check the resistance of the wires with an ohm meter. This is done with engine off. Wiggle the wires as you check resistance. It should not vary. In general, the bad one will have a much higher resistance than the others.

The one that rubbed on the hood would be suspect.

Another thing you could do is get piece of well insulated wire, like the wire that runs through your house walls. Ground one end to engine block and run the other bare end along each spark plug wire with engine running. If a wire is bad, you will see sparks jump.

The problem could also be your distributor cap or rotor button. Good luck.

[Bob's944]

Ditto what he said on replacing the plugs. It's best to torque them properly, 20 ft-lbs is good, and make sure you use the washer that comes with the new plug, don't reuse the old one

If you are noticing arching spots from the wires, they are bad, and prolly kinda prone to shock you if you get too close to them when it's running. There shouldn't be any cracking in the actual wires themselves, you're probably gonna see some in some of the boots and fittings and wire guides. When you get the plugs out, check them out. If they have any carbon deposits, kinda dry n sooty, that's a sign of weak ignition. If the wires are bad, chances are the distributor and rotor are ready to be replaced also. A bad distibutor get's worse when it's wet also.

[944S Boyeee]

FlyinAh - how do I get my wires off the plugs - just pull up?? I'm afraid to break something.

[Booster]

The caps can be a PITA to get off sometimes, and whatever you do don't crossthread your plugs when you install them and use a little antiseize on your threads of your sparkplugs.

[mlue]

Originally posted by 944S Boyeee
FlyinAh - how do I get my wires off the plugs - just pull up?? I'm afraid to break something.

Boteee, you should really head on down to a Canadian Tire store and order your self a Haynes Manual for the 944. Granted the manual is for the older car but alot of the proceedures are the same. I think they are $17 Canadian, money well spent. If they donn't have it is stock they can order it in.

Mark
'86 944NA

[944S Boyeee]

I actually have one on order.....I know I need one of these things. I don't do any "real" work on cars - but the lil' things I can do and I'm sure I will pick up some others as I learn. I have a Suzuki Sidekick and I managed to change the fuel filter, the Cam gaskets, the head gasket, valve seals, cleaned the fuel injector by hand, rebuilt my FWD hubs, installed window regulators, put in a new hood release cable and other stuff - not bad for a guy who can't remember the names of screwdriver heads!!! "Is it Phillips or flat head, I just can't remember" (lol).

I'm a "tinkerer". Give me a broken VCR and I can make it work - it may come back with some extra black tape and a few rubber bands here and there - but I'll make it work damn it!!! It may have a few "extra" screws that didn't make it back in, but it will work - but I can easily buy another one if I really screw up.......

But I won't tinker with anything important on my Porsche. I'll only be changing things I can see, touch and/or change with basic tools. Spark plugs and stuff I will start out with and see where I go from there. Can't afford to do something wrong with that car - it ain't no VCR.

[AFJuvat]

Well first off, if there is a burn spot on your car where your wires were touching it - it is bad, the insulation is cracked and the wires need to be replaced - replace them. Jacobs makes excellent low cost alternatitives to OEM wires.

Check your cap and rotor - chances are, they are on their way out as well.

Now for some specifications:

First off, buy yourself a torque wrench - they cost around $50 (US) Surprisingly, many things on a Porsche are not torqued down nearly as tight as you would think, and it is easy to crack and/or strip things out.

Torque: (For clarity, all specifications are in metric)

Sparkplugs: tighten to 25 - 30 Nm
Sparkplug Gap: 0.7 - 0.8mm

Cylinder arrangement:
#1 is at the front of the engine, #4 is at the rear therefore: 1-2-3-4

Firing order is 1-3-4-2

On the distributor cap:

1: Lower Right
3: Lower Left
4: Upper Left
2: Upper Right

Hope this gives you a steer in the right direction

AFJuvat

[944S Boyeee]

Does Jacob's have a website??? Or a phone number (I forgot about that old technology).

[AFJuvat]

You can get them from automotion

www.***************

AFJuvat

[mdevine]

Be careful when you order the wires for a 944S . I have twice been told that I was getting 944S wires and was sent wires for 944. They are very different. The only 944S wires I have seen go for around $200. Please post if you/anyone has found different.