Testing for spark, coils and power pack - Beginner

[rbeaudoin]

OK I understand the concepts, I've read the secret file and about a million posts. I'd like to summarize what I think I need to do and in what order and hope someone can fill in the blanks. I'm a beginner, have only a multimeter and no specialty tools and hope I can accomplish what I want.

Spark Test. I was going to charge the starter battery, warm up the engine with muffs, disconnect the fuel line, remove the sparkplugs, then while connected to the coils (one at a time) crank the engine over for 2 seconds with WOT and see if I have spark. Is this a reasonable way of checking for spark?

Coil test. After my spark test if I find one that doesn't get spark I was going to connect the positive end of my multimeter to where the spark plug wire connects to the coil (the pole?) (removing the wire). Where does my negative end go? And I was going to crank over the engine for 2 seconds to see if I get a reading. What should be an acceptable reading?

Power Pack. If I don't get a reading on the coil I was then going to disconnect the coil from the power pack and do the same test with the power pack wire. Again where does my negative multimeter end go? And what should I expect as a positive reading?

If I get nothing from the power pack I will replace the powepack. If the power pack is successful and the coil fails I will replace all 3 coils and keep the 2 good ones as emergency spares. Does this make sense and will I achieve what I want? To isolate an ignition problem?

 

[tashasdaddy]

Re: Testing for spark, coils and power pack - Beginner

i use an $8.00 spark tester from auto parts store, set the gap at 7/16 inch. ground always goes to a good place on the block of the motor.

if i do not have spark on one or two coils, i take the good coil, and swap places with the bad coil and retest. if the problem follows the coil then the coil is bad. if the problem stays at the cylinder, then we usually investigate why. it is very rare for 2 coils to go bad at the same time, if you have multiples not firing, it is "usually" the power pack.


also buying a clip on remote starter switch, $10.00 make this so much easier, you clip one lead to incoming pos post on the solenoid, and the other to the small post next to it. (that is if it is wire correctly, sometimes you have to connect to the other small post). then you turn the key to "ON" and just mash the remote switch to turn the motor over.

spark tester

 

[rbeaudoin]

Re: Testing for spark, coils and power pack - Beginner

i use an $8.00 spark tester from auto parts store, set the gap at 7/16 inch. ground always goes to a good place on the block of the motor.

if i do not have spark on one or two coils, i take the good coil, and swap places with the bad coil and retest. if the problem follows the coil then the coil is bad. if the problem stays at the cylinder, then we usually investigate why. it is very rare for 2 coils to go bad at the same time, if you have multiples not firing, it is "usually" the power pack.


also buying a clip on remote starter switch, $10.00 make this so much easier, you clip one lead to incoming pos post on the solenoid, and the other to the small post next to it. (that is if it is wire correctly, sometimes you have to connect to the other small post). then you turn the key to "ON" and just mash the remote switch to turn the motor over.

So when I connect the spark plug tester do I disconnect the other sparkplugs? Or leave them all in and simply connect the wire from the coil to the tester?

 

[tashasdaddy]

Re: Testing for spark, coils and power pack - Beginner

you posted while i was editing. you remove all plugs. you were on the correct track, this is just a little easier.

 

[dwco5051]

Re: Testing for spark, coils and power pack - Beginner

Coil test. After my spark test if I find one that doesn't get spark I was going to connect the positive end of my multimeter to where the spark plug wire connects to the coil (the pole?) (removing the wire). Where does my negative end go? And I was going to crank over the engine for 2 seconds to see if I get a reading. What should be an acceptable reading?


Don't try this!!! If every thing is OK up to this point you will not only have any speciality tools but you won't have a meter anymore either. The gap tester will tell you all you need to know. 30,000 or so volts on the secondary side is not good for meters.

 

[rbeaudoin]

Re: Testing for spark, coils and power pack - Beginner

Thanks! I'm putting away the multimeter. I'm going to go get an inline spark tester tomorrow from Napa and go from there. If I find one that isn't working I will switch the coil with one that is and retest.