Tune Up Suggestions.

[Thunder-71]

Hi Guys,
This is the 5th year I am running my 1984 NA with all Bosch Ignition components (spark plug wires 7mm-Silicone-High Temperature, cap and rotor and coil), they were on the car when I bought it 5 years ago. Excellent performance for everyday driving with over 50K miles from me plus POs. Time to replace them since I am having some hesitation issues especially on cold mornings. Should I replace them with same since are proven to me, or are they better alternatives that will not brake the Bank?

[v2rocket_aka944]

I never understand why people replace spark plug wires if they aren't damaged.
Hesitation when cold is unlikely to be a spark problem.

Check the condition of your cap/rotor and replace the plugs...but there's probably something else going on.

[Tom944]

I had hesitation and then loss of power on cold mornings. Replacing the oxygen sensor fixed it.

[John_AZ]

Parts that should be replaced after 50K or more unknown miles:
FPR
FPD
O2 sensor
Fuel filter
Fuel tank screen
Rebuild the throttle body if you see a pool of oil inside
Check the "J" boot for rot
AOS seals
and all the basic maintenance items in the owners manual, that book in the glove box.

How many have never been changed? One may not make a difference. A combination of replacement parts will.

J_AZ

[ckelly78z]

It's probably wise to replace your cap and rotor, and plugs if they have that many miles on them, but you might look at the inside of your old cap to see if there is a buildup on the end of the four contact points. You'll also want to check out the end of your rotor. Sometimes a little sand paper applied to these areas to get back to metal in necessary. Make sure your plugs are gapped properly, and you might consider running some fuel injector cleaner through the system.

[Rasta Monsta]

Originally Posted by v2rocket_aka944

I never understand why people replace spark plug wires if they aren't damaged.

I'll never understand how people think they can visually inspect a component that invisibly degrades with heat and time.

[Rasta Monsta]

Originally Posted by v2rocket_aka944

I never understand why people replace spark plug wires if they aren't damaged.

I'll never understand how people think they can visually inspect a component that invisibly degrades with heat and time.

[v2rocket_aka944]

Originally Posted by Rasta Monsta

I'll never understand how people think they can visually inspect a component that invisibly degrades with heat and time.

Forgive me, but how does a spark plug wire degrade over time?
If there is spark at the distributor end, and spark at the plug end, seems the wire is doing OK?
If there's no cracks in the external insulation or exposed/broken wiring, what really is there to fail?

The wires on my car have not been changed in the 10 years I have owned it and I strongly suspect them to be factory original from 12/1984...what would I stand to gain by replacing them?

[djnolan]

I guess I will take a moderate political stance in this discussion. The porsche plug wires are a lot better than the typical detroit setup with a core that will gradually burn out with time. The way to test them is to check the resistance and if memory serves me right it should not exceed 6k Ohm per foot. This varies by manufacturer.

That being said, I have checked several sets of 944 wires and none of them were approaching that. Most of them have a solid core or a high impedance core that is very durable. What I did find is some of the wire sets have a screw on boot at each end that can loosen up and might affect performance if it gets loose with age. A quick twist is all it takes to tighten it up and you can spend your hard earned dollars on other things the car needs.

[Rasta Monsta]

Originally Posted by v2rocket_aka944

Forgive me, but how does a spark plug wire degrade over time?

Metal spring clips at both ends weaken and corrode due to vibration and the elements. Resistance through the wire slowly increases. Boots harden and lose their effectiveness, allowing moisture into connections. Insulation slowly degrades and begins absorbing water.

If you are running 30 year old factory installed wires, I guarantee you are losing fuel economy and power.