Engine electronics gurus: Fried Coil?

XJZ · Jan 22, 2004

As far as I can tell I'm not getting spark from the coil.

I pulled the boot off at the dist, stuck a screw driver in the boot and connected it to ground, no spark.

Does this definately mean it's the coil, or could it still be something else such as the crank sensor. What do I do to get the coil tested? I hope it's just as easy as replacing the coil.

And if it is the coil, what's a good price and where?

TIA

5-90 · Jan 22, 2004

The coil can be tested directly with an ohmmeter, but I don't have the value handy (check a service manual.) Before you do that, though, put an old spark plug in the distributor end of the coil wire and use the gap to check for spark - I keep a couple old plugs around just for that.

When you put a rod of some sort into the boot and touch it to ground, you won't get a spark since there is no gap. There has to be a gap for the spark to jump or it just won't happen.

So, I'd do that before I even pulled the coil, just to make sure. If that is okeh, I'd check the rotor for excessive carbon deposits, as that will inhibit sparking all around. Also, checking the inside of the distributor cap and the contact button in the centre is a good idea...

5-90

XJZ · Jan 22, 2004

5-90 said:
The coil can be tested directly with an ohmmeter, but I don't have the value handy (check a service manual.) Before you do that, though, put an old spark plug in the distributor end of the coil wire and use the gap to check for spark - I keep a couple old plugs around just for that.

When you put a rod of some sort into the boot and touch it to ground, you won't get a spark since there is no gap. There has to be a gap for the spark to jump or it just won't happen.

So, I'd do that before I even pulled the coil, just to make sure. If that is okeh, I'd check the rotor for excessive carbon deposits, as that will inhibit sparking all around. Also, checking the inside of the distributor cap and the contact button in the centre is a good idea...

5-90

Thanks man, I'll give it a shot. Glad I didn't already assume the coil was dead, I'll try want you suggested!

89xj · Jan 22, 2004

i would check the CPS and wiring harness first. if the CPS is bad you wont get any power to the coil. try unplugging the wiring harness to the cps clean and apply dialectric grease and reconnect. havent heard of too many coils going bad.

XJZ · Jan 22, 2004

89xj said:
i would check the CPS and wiring harness first. if the CPS is bad you wont get any power to the coil. try unplugging the wiring harness to the cps clean and apply dialectric grease and reconnect. havent heard of too many coils going bad.

I'll check that, too. Thanks.

Without looking at it, is just a snap in plug? It's tight up there!! Also, your reffering to the sensor end, right?

I know, I'm a dunce. :dunce:

RookieJeeper · Jan 22, 2004

he's referring to the plug end. Sometimes you can unplug the sensor and plug it back in a couple of times, and this seems to be a temporary fix to get it running.

Runnin'OnEmpty · Jan 23, 2004

XJZ, the coil resistance readings should be about 1 ohm or less measured from the primary terminals (pos & neg). Also check between the pos/batt coil terminal and the tower/cap terminal - this should be anywhere from 6K to 30K ohms. If the coil is bad, you'll probably read an open at one of these tests.

Another test is to put 5-90's spare plug on the coil output terminal, ground it, and have someone turn the key on and off without engaging the starter. When watching the plug, you should see the plug spark one time. If it sparks, look elsewhere for the problem, CPS, etc. If it dosen't spark, then take a closer look at the coil; and also check the positive coil connector for 12v.

Engine electronics gurus: Fried Coil?

XJZ

NAXJA Forum User

5-90

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XJZ

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89xj

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XJZ

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RookieJeeper

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Runnin'OnEmpty

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