Hemi spark plug wires

[dart6]

Hi
I'm having no luck finding the resistance of these 8mm silicone wires online. I relaced the plugs with BPR5ES but there seems to be a slight misfire at low revs. The misfire was more pronounced with the original RN14YC plugs.
Anyway i'd like to test the wire resistance but i don't have a figure to go on.
Are these silicone wires any good they appear newish?

 

[AR67GTX]

I would try to isolate 1 cylinder at a time by grounding the wire to see if you can find the cylinder misfiring. Then measure the resistance and examine the wire carefully for damage or possibly a bad terminal connection. If the wire looks good then measure the end-to-end resistance of another wire that is closest in length to the suspected bad one. If they seem to compare closely then I would start looking at other potential causes of the miss.

Another thought. Idle the car at night in darkness at night and look for any sign of arcing and leakage from any of the wires.

 

[toolmanmike]

I would try to isolate 1 cylinder at a time by grounding the wire to see if you can find the cylinder misfiring. Then measure the resistance and examine the wire carefully for damage or possibly a bad terminal connection. If the wire looks good then measure the end-to-end resistance of another wire that is closest in length to the suspected bad one. If they seem to compare closely then I would start looking at other potential causes of the miss.

Another thought. Idle the car at night in darkness at night and look for any sign of arcing and leakage from any of the wires.

A little spritz of water from a spray bottle will start the fireworks at night.

 

[dan juhasz]

If the wires ohm out less that 25k they are fine. check the insulators carefully for tiny burn throughs, same thing with the boots themselves.

 

[dart6]

I would try to isolate 1 cylinder at a time by grounding the wire to see if you can find the cylinder misfiring. Then measure the resistance and examine the wire carefully for damage or possibly a bad terminal connection. If the wire looks good then measure the end-to-end resistance of another wire that is closest in length to the suspected bad one. If they seem to compare closely then I would start looking at other potential causes of the miss.

Another thought. Idle the car at night in darkness at night and look for any sign of arcing and leakage from any of the wires.

How do you ground the wire?
I did the visual last night before i posted, nothing to see

 

[dart6]

A little spritz of water from a spray bottle will start the fireworks at night.

I'll do that tonight

 

[dart6]

If the wires ohm out less that 25k they are fine. check the insulators carefully for tiny burn throughs, same thing with the boots themselves.

Thanks

 

[6PKRTSE]

I would try RN12YC plugs over the 14's. 10's if you can find them. I doubt it is the wires causing the misfire on a Hemi since the wires go no where need the exhaust manifols/headers.

 

[AR67GTX]

How do you ground the wire?
I did the visual last night before i posted, nothing to see

Well, it’s not to hard on most engines where an insulated probe clipped to a ground can be slipped in between the plug boot and plug wire to short the plug circuit. “If” you have points ignition and your plug wires pull off pretty easily (I say “if” as mine are very difficult to pull off the plug on my Hemi) just pull them one at a time with insulated plug pliers to see if there is any change in rpm or missing.

If you have electronic ignition it might not be a good idea to simply pull the wire off the plug as some can be damaged that way. In that case it’s probably easiest to get an old plug wire, hook a ground clip on one end and secure to a ground and replace each wire with it, one at a time at the distributor cap. If you get to a cylinder and the rpm’s are unchanged from when all 8 cylinders were hooked up, that is the one missing. You should get a noticeable rpm drop on the other cylinders as it’s running on 6 cylinders. Of course you have to stop/start the engine for each cylinder’s test.

I would try the check at night first with the spritzer bottle.

 

[RJRENTON]

I would try RN12YC plugs over the 14's. 10's if you can find them. I doubt it is the wires causing the misfire on a Hemi since the wires go no where need the exhaust manifols/headers.

Consider trying Champion RC-12YC......Same as RN-12YC ......same 3/4" reach, but have a 3/4" hex rather than 13"/16 hex....same projected core, same heat range....or AC R43XLS........just a thought.....
BOB RENTON

 

[Geoff 2]

Keep your NGK plugs. They are the correct heat range & not the cause of your problem unless you have one that is faulty [ unlikely ]. Measure the resistance of the plugs, terminal on top to centre electrode, should be 3000-7000 ohms. Check for carbon tracking inside the dist cap.
For best performance & reliability, you should use spiral wound [ also called helical ] plug leads. These have a metal conductor, usually copper or s/steel. They all have low resistance [ compared to carbon leads ] & the actual resistance [ ohms per foot ] doesn't matter as this test showed.