coil resistance - Toyota Nation Forum : Toyota Car and Truck Forums

speedyts49 · 04-02-2005, 10:56 AM

My coil shold read from .4 to .5 ohms but It fluxuates from 0 to .8. Is this normal or could this be a sign of a shorting/going bad coil?

fredk · 04-02-2005, 01:38 PM

0?

marcuslogsdon · 04-02-2005, 02:36 PM

did you test the leads to see how much resistance is in the leads themselves? usualy there is 1-2 ohms.

make sure you disconnect the high-tension wire when checking the primary side of the coil. (test the positive and negitive terminals) and yes it should be .4 - .5 ohms

check the secondary side too (check the positive terminal and the high-tension terminal) it should read 10,000 - 14,000 ohms.

speedyts49 · 04-02-2005, 06:31 PM

Quote:

Originally Posted by marcuslogsdon

did you test the leads to see how much resistance is in the leads themselves? usualy there is 1-2 ohms.

make sure you disconnect the high-tension wire when checking the primary side of the coil. (test the positive and negitive terminals) and yes it should be .4 - .5 ohms

check the secondary side too (check the positive terminal and the high-tension terminal) it should read 10,000 - 14,000 ohms.

I did not test the leads. Doesn't that factor in when using a digital multimeter?

i did disconect the high-tension wire and got a 0 to .8 ohms. IT just kept going up and down on my meter. This is what has me thinking something is wrong with the coil.

The secondary was good at 13k.

Thanks for the reply. I am going to get an aftermarket coil and at worst I'll have a spare.

marcuslogsdon · 04-03-2005, 01:21 PM

you might want to use a digital multimeter from now on. much more reliable for testing resistance

speedyts49 · 04-03-2005, 01:43 PM

Quote:

Originally Posted by marcuslogsdon

you might want to use a digital multimeter from now on. much more reliable for testing resistance

Yes thats what I have. Pretty handy tool. It was about $80 at Sears.

Pineapple · 04-04-2005, 09:54 AM

Go to junk yard and get one long spark plug cable. You'll need one to rewire the aftermarket coil.

speedyts49 · 04-04-2005, 04:18 PM

You say i'll have to rewire the aftermarket coil? We're talking about the ignition coil right?
I aslo found a water temperature sensor to not be working or at least it does not show resistance on the multimeter.

jpdiehl · 04-05-2005, 01:29 PM

Have you tested power going to the coil? Both with the + and - leads attached and without? Coil resisstance is low on these. Primary around .6 ohms, and secondary arount 9,000 to 11,000 ohms.

speedyts49 · 04-05-2005, 01:35 PM

I disconnected the cable from the distributor and pulled the plug connected to the coil then I did the two tests the factory manual suggested. The secondary was good but the Primary was going up and down from 0 to .8 which was weird.
I'm not sure how else to test it.

marcuslogsdon · 04-05-2005, 10:01 PM

well you can do a couple things. test a buddies coil and see if you get the same results. take it to the auto part store and see if they will let you test a brand new one. i wouldn't buy an aftermarket coil unless you are positive it is the coil.

speedyts49 · 04-05-2005, 10:21 PM

Yeah I hoping the (one part two names-thread) is the answer once I get the part.