Jeep Commander Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
3,037 Posts
Discussion Starter #1
I've just installed brand new ignition cables in my 2010 3.7L.

Yes, some M/Y Hemi's, 4.7L and 3.7L have a single coil pack to plug with no cables in between. Other M/Y do have ignition cables installed. My 2010 3.7L have coil packs on the driver's side bank with ignition cables running to the passenger side bank, for a wasted spark type arrangement.

Something people don't realize, the super high voltages for spark plugs, traveling through the cables will create all sorts of EMI/RMI that interferes NOT only with the radio, but the sensors and electronic engine management. The is why ignition cables are NOT solid metal wires. To reduce the EMI/RMI they are usually some sort of flexible resistive conductor, like carbon impregnated latex, that makes them one long flexible resistor. Thing is, this conductor breaks down with time and use and you do NOT get a strong a spark from the coil.

So, at 118k miles, I've replaced the ignition cables, yep it was a noticeable difference. Even though I just did the plugs a month ago, with fresh cables the engine is idling smoother, seems to have a little more pep, and just the short drive today is showing a 1.5 mpg increase over more average (I reset the average mileage).

So, you've got a Commander with a year engine that has ignition cables and you've got close to or more than 100k miles, I'd consider replacing them!
 

·
Registered
Joined
·
1,585 Posts
I've just installed brand new ignition cables in my 2010 3.7L.

Yes, some M/Y Hemi's, 4.7L and 3.7L have a single coil pack to plug with no cables in between. Other M/Y do have ignition cables installed. My 2010 3.7L have coil packs on the driver's side bank with ignition cables running to the passenger side bank, for a wasted spark type arrangement.

Something people don't realize, the super high voltages for spark plugs, traveling through the cables will create all sorts of EMI/RMI that interferes NOT only with the radio, but the sensors and electronic engine management. The is why ignition cables are NOT solid metal wires. To reduce the EMI/RMI they are usually some sort of flexible resistive conductor, like carbon impregnated latex, that makes them one long flexible resistor. Thing is, this conductor breaks down with time and use and you do NOT get a strong a spark from the coil.

So, at 118k miles, I've replaced the ignition cables, yep it was a noticeable difference. Even though I just did the plugs a month ago, with fresh cables the engine is idling smoother, seems to have a little more pep, and just the short drive today is showing a 1.5 mpg increase over more average (I reset the average mileage).

So, you've got a Commander with a year engine that has ignition cables and you've got close to or more than 100k miles, I'd consider replacing them!
Thanks for sharing :clap:

I'll have to inspect mine. They are @ 102k miles now i believe.
 

·
Registered
Joined
·
3,037 Posts
Discussion Starter #3 (Edited)
Well the detioration is internal, you won't be able to tell by inspecting the external insulation.

I've seen tests where you can use a multi-meter and test the resistance of the ignition cables. Usually there are specs with tune-up specs or in the FSM stating the resistance range per foot of the ignition cable, if it goes above that in resistance, time to replace it.

The higher quality and more modern cable would last longer, as well they make "Suppressive" cables that do NOT detiorate with age/use. In the past, cable would detiorate to the point they effected engine performance by 60k miles, today I think you wouldn't have a problem less than 100k miles, but again, it all depends.

Personally, I just replace the cables every couple of plug changes, by the 4th plug change usually.
 
1 - 3 of 3 Posts
Top