Does an ignition coil ground?
08-11-2019, 05:00 AM
#16
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Year: 1997
Model: Cherokee (XJ)
Engine: Straight 6 4.0L
I just checked the FSM to try and be as accurate as possible. There are 2 grounds involved at the ignition coil. One that is driven by the PCM that is the driver for the ignition coil, and it would be coming in via the ignition coil connector. Then the other ground shown is a case ground, meaning the engine block. In the diagram it does not show the coil + voltage continuing on to the distributor and the plugs. But if it went directly from the coil to the engine block it would effectively be a short circuit, and no voltage would ever reach the distributor or the plugs.
So I'm going with my original answer. The ignition coil does not depend on its mounting bolts to provide ground for its functionality.
But the bolts it mounts to do serve as important connection points for grounding the engine block (which many things depend on). So if they were not connected back to battery negative, you could have a no-spark situation (because the block is not grounded).
So I'm going with my original answer. The ignition coil does not depend on its mounting bolts to provide ground for its functionality.
But the bolts it mounts to do serve as important connection points for grounding the engine block (which many things depend on). So if they were not connected back to battery negative, you could have a no-spark situation (because the block is not grounded).
Hey bud I know Im super late to this conversation but I'm currently having a no spark condition very similar to what you was just describing... Mine coil mount bolts have two looped ends per bracket stud... So I have 4 all together! Feel as if maybe I got them mixed up and have caused the no spark headache I'm battling. You said you just finished double checking the FSM ?? Any way you could share that with me so maybe I could see if I have mine connected wrong and maybe straitn my mess out! I would be very grateful. Thank you for your time
08-11-2019, 05:21 AM
#17
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Year: 1995 RHD
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Engine: 4.0l
Hey bud I know Im super late to this conversation but I'm currently having a no spark condition very similar to what you was just describing... Mine coil mount bolts have two looped ends per bracket stud... So I have 4 all together! Feel as if maybe I got them mixed up and have caused the no spark headache I'm battling. You said you just finished double checking the FSM ?? Any way you could share that with me so maybe I could see if I have mine connected wrong and maybe straitn my mess out! I would be very grateful. Thank you for your time
11-10-2022, 04:58 PM
#18
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Worth a try
Hey guys, I just got a real quick question. So I got a mechanic to come give me a diagnostic on why I got no spark and my ignition coil was just hanging and wasn't bolted to the engine block as it should be and he said he's 100% that's the problem. So does the ignition coil need too be bolted to the engine block or was he just blowing smoke up my a** to get my money and run. Thanks
11-10-2022, 08:20 PM
#19
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Year: 1988
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Engine: 4.0
Electricity flows in circles that we call circuits. If the circuit is open, electricity won't flow. Your coil is a positive ground electical circuit which is backwards of the other circuits in the car. This helps the spark start at the center electrode of the spark plug and jump to the outer instead of the other way round which would give a less uniform and stable spark. So your coil will need an even number of wires to work if it hangs in the air: one in, two out, on the primary side, and three in and four out on the secondary side. The spark side circuit goes from the coil through the distributor to the correct plug wire and then center electrode, across the gap to the outer electrode which is part of the plug body, through the cylinder head and has to get back to the coil. That's usually done by the mounting of the coil to the block or head in a way that provides a solid electrical connection. You could hang it from a wire similar to a plug wire and get the job done.
This all looks a little different for coil on plug systems since you don't have one coil feeding all the plugs, and on wasted spark systems since you still have more than one coil each feeding a pair of plugs. But the circuit must still be completed.
This all looks a little different for coil on plug systems since you don't have one coil feeding all the plugs, and on wasted spark systems since you still have more than one coil each feeding a pair of plugs. But the circuit must still be completed.
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