Spark plugs and cables ?

[Hendrik]

Impreza 1993 , 1800 , AWD , automatic

 

After a long downhill road in third gear (10 miles) no use of accelerator at all , one of the (new) spark plugs fail. It is black , wet from oil and gasoline.

The engine only runs on 3 cylinders afterward.

Measuring the resistivity of the relavant cable showed double the normal resistance. The plugs itself are resistive as well.

I put a standard copper wire in parralel with the cable , the behavieour

is better at again the same road.But not perfect , depending on speed , the engine runs still on only 3 cylinders.

At some time I will replace all cables , but I have to wait 4 weeks for delivery. How important is the match of all resistive values (cables and plugs) in total ?

Is there another component involved in the problem ?

[nipper]

Spark plug cables are far more complicated then what your measuring.

 

If you have a mechanical distrubutor it really doesnt make that much differnce, as your talking 100,000 volts. If you have a waste spark system, the two wires on either side of the coil should balance.

 

I hope you ordered Subaru wires. Wires are affected by temperiture, how they interact with other wires, and engine load. None of those you can measure with a meter.

 

I think you have a bigger problem. There really should be no oil in the sparkplug. The plug is oil fouling on decceleration. Burning oil on acceleration is bad valaves, on decceleration its rings. You need to do a compresion test and see whats going on inside the engine. You need to do it both wet and dry. A bad spark plug wire wont cause what your seeing.

A bad plug wire would/might cause a miss under load or damp conditions. Put the old wire back on and get a compression test done.

 

 

nipper

[idosubaru]

wires should only be Subaru on this engine.