I pulled #1 and #3 spark plugs before I did my engine flush...


#1 is dark... it looks like it was running cold, with deposits forming.

#2 is normal.. Clean looking, no hot stops, no carbon deposits.

I began to suspect a serious problem. my Car felt good though.


This is my 3rd set of NGKs in one year by the way. I had spark plug failures with the previus sets so I was suspecting this brand new plugs woud eventually crap out of me.

So when I pulled the plugs... I realise #1 began to look like my previous plugs that failed and misfired on me... I went the NGK route again and this set too looks like it was on its way out already. I replaced the two plugs with two brand new Bosh single Plats and it is running smooth... I think I caught the problem before it began to manifest.

I was ready to start blaming my engine and ignition system for the #1 plug...however two days ago i was at the NGK website when I came across a writting that states some MSD ingnitions are capable of burning up the resistor inside the spark plugs. It goes to say it burns the resistors inside the Spark Plugs so they recomend a diff type of spark plug. They sell special sets of spark plugs to go witht he most Powerfull Capacitive Discharge Ignitions. Anywho.. I only have an MSD6A so I didnt think anything of it... except that tonite I decided to measure the resistance of both spark plugs and sure enough...... The good one has a resistance of 3k ohms .. the bad one is 36 k ohms... 10 times more resistance to electricity of the good spark plug.

I remember the writting to say that if a spark plug resistor was more than 5 k ohms then it was called an open circuit.... I dont remember the exact words... but I think thats the problem I am having with the spark plugs. I either purchased batch of plugs with bad resistors or my MSD6a is slowly burning them up. Maybe the bad resistor plugs are mixed with good ones so its hard to tell from the get go.

I will suggest to measure the resistance of all the brand new spark plugs before they are installed. 10 times the resistance means 10 times less power delivered for spark at the cylinder.. I agree with a maximum resistance allowed. NGK website states 5k ohms I remember... so anything more does not pass the resistance test... I will go with that.


I hope you guys find this info Helpfull. I also took a picture of the two spakplugs side by side if someone wants it... just tell me where to send it or how to post it.

Marvin

 

So what if you use non-resistor type plugs?

 

I want to try them... if I can find the correct part number. First thing I am going to ckeck if for Radio Interference of any kind cause that could screw up my PCM operation.

I have Spiro Pros so I figure they would probably handle the RF. Any idea what non-resistor spark plug I can try for my #1 cylinder? I can use a small portable am radio and get it real close to the spark plug to hear for any radio interference...


Anyone know the non-resistor spark plug that can be used?


Marvin