Spark Plug wire resistance specs

silver_power

Petty Officer 1st Class
Joined
Jul 8, 2009
Messages
321
Hello, does anybody know what is the resistance of the spark plug wires?
I have a 350 Mag MPI 2009 (sn:1A348183) with the flat distributor cap and i measured the resistance of the wires. The readings are 16,3-15,3 , 12,22-14,02 , 11,00-10,63 , 10,9-11,76 KΩhm for the No1,2(longer wires) , 3,4 , 5,6 , 7,8(shorter wires) Cylinders and 8,45KΩhm for the coil wire.
I ordered a new marine wire kit for my engine but they sent me by mistake the half kit, i mean for the cylinders 1,3,5,7 and the coil wire- so the lenght are equal to original . I measured the resistance of the wires and the readings are 3,7kΩhm for the longer wire and 1,98kΩhm for the shorter. There is a huge difference.
The new kit is for the newer style mercruiser with the dizzy cap like mine, mag wire , silicone, for marine use.
Has anybody ever checked the resistance of the wires and what were the readings?
As i have some surging issues (another post) and already changed cap, rotor, plugs, fuel pressure checked ok 43psi, and no fault code to scan tool and still the surging exists, is it maybe that my wires with this resistance are the problem?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,548
Hello, does anybody know what is the resistance of the spark plug wires?
I have a 350 Mag MPI 2009 (sn:1A348183) with the flat distributor cap and i measured the resistance of the wires. The readings are 16,3-15,3 , 12,22-14,02 , 11,00-10,63 , 10,9-11,76 KΩhm for the No1,2(longer wires) , 3,4 , 5,6 , 7,8(shorter wires) Cylinders and 8,45KΩhm for the coil wire.
I ordered a new marine wire kit for my engine but they sent me by mistake the half kit, i mean for the cylinders 1,3,5,7 and the coil wire- so the lenght are equal to original . I measured the resistance of the wires and the readings are 3,7kΩhm for the longer wire and 1,98kΩhm for the shorter. There is a huge difference.
The new kit is for the newer style mercruiser with the dizzy cap like mine, mag wire , silicone, for marine use.
Has anybody ever checked the resistance of the wires and what were the readings?
As i have some surging issues (another post) and already changed cap, rotor, plugs, fuel pressure checked ok 43psi, and no fault code to scan tool and still the surging exists, is it maybe that my wires with this resistance are the problem?

surging is fuel system related 99.999999% of the time

the crab-cap should be changed every few years. its a bad design, and has a tendancy to short out internally. you did change the cap and rotor, correct.
 

silver_power

Petty Officer 1st Class
Joined
Jul 8, 2009
Messages
321
I agree with you but i checked the fuel injectors (all was good) and the fuel pressure is normal (42-43psi) when cruise and surging. So i think that something happens with the ignition components, but this has been discused to another topic of mine. That is why i opened new topic concerning the spark plug wires.
 
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