Sparkplugs???????

Just wondering if anyone has any ideas on this matter????????????????

Ive got an R30 Skyline ie 1982 2.4litre injected motor. She runs great most of time, maybe a little low on compression but doesnt oil up plugs and plugs look fine. She doesnt ping and timing is correct etc. However No 4 cylinder burns out a plug after 3000 to 8000kms. Sometimes i get 100 kms out of a plug in No 4. The plug is basically dead after that. The plug looks just like all the others if compared....... replace it and she goes again fine. Ive talked to auto electricians and they have no idea

Suggestions?

Reply to
lee
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Reply to
Sarky

What brand of plugs? Bosch platinums?

Reply to
Steve

Just some ideas, probably wrong but I've a lot of high voltage hostile environment experience in military electronics (and they go wrong all the time), so for what it's worth...... Are they resistor plugs? Measure with an ohmmeter from the connector to the tip, should be the same as the good plugs within 20% ish. Could be going high in resistance due to too high a voltage & current, the only causes I can think of are a very wide gap in the distributor cap/rotor arm for that HT lead (I don't know if an R30 has a distributor) and perhaps an open circuit HT lead where the spark is jumping an internal gap so you don't notice anything wrong you just get a higher voltage developed before the plug will fire. Another cause of resistor failure is engine vibration, this would have to be worse just on that cylinder though, so it would have to be a high frequency resonant mode local to that part of the engine or the other plugs would suffer as well, perhaps a worn bearing on that cylinder or just a loose bolt? A length of tubing used as a stethoscope should be able to tell you if there's extra noises in that cylinder area. A different brand of plug may help (I like NGK in Japanese motors).

Reply to
Steve B

anything does it

Champi>

Reply to
lee

I don't think it's the sparkplug. It may be a bad cable or connector. The plug is fouling. Also check your grounding wires from the engine to the chassis.

Reply to
Joseph Wind

Try the right NGK's and then when the plug "dies", swap it into another hole instead of replacing and see what happens. Might be a clue.

Reply to
Steve

The plug is not fowling........... Looks to be running in perfect condition

Reply to
lee

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