How much of an affect will the air temperature have on the measured resistance values when ohming out the stator?I was testing my converted 98 with the 2000 ignition this afternoon and found the pickup coil in spec but the charging coil is almost twice the spec from the service manual.It's supposed to be .36 - .44 ohms but my meter is reading .7 to .8 ohms.I 'm doing the testing in my shed and although I have a heater on and it's warmer than the outside,it may not exactly be room temperature but it's pretty close.
Vmax540
VIP Member
If your meter has a zero function put the leads together and zero. This eliminates the resistance of the leads which can be a factor with such low readings. Otherwise with the meter leads together note the reading and subtract from the coil readings.
roudyroy1
Active member
Well I was tracking an misfire last year(ended up being a rusty flywheel) and I tested the stator in my garage on a -5 day and it was very close to being out of spec, took it to the shop and it tested dead centre of where it should be. So it does have some effect, how much is hard to say.
Time for some theory:
Now, as a metal conductor cools, the more conductive it becomes(less resistance). So in theory, you should have a lower reading now in your cooler work place compared to a room temp garage, not higher as you have seen. practice doesn't always represent theory so I would test it in room temp anyways before doing anything.
Hope that helped!
Just out if curiosity, are you using s decent brand of multi meter?
Time for some theory:
Now, as a metal conductor cools, the more conductive it becomes(less resistance). So in theory, you should have a lower reading now in your cooler work place compared to a room temp garage, not higher as you have seen. practice doesn't always represent theory so I would test it in room temp anyways before doing anything.
Hope that helped!
Just out if curiosity, are you using s decent brand of multi meter?
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Well it's not a Fluke but yeah it's a good quality one. I thought about poping the stator off and taking inside for the night then testing it. I wonder if I just took a heat gun and set it on low and let it run for a few minutes on the flywheel to warm the area up if it would help.
roudyroy1
Active member
considering how its double the spec and the theory says it will get worse once you bring it into a warm environment, i'm going to go out on a limb here and say its going to need to be replaced. might as well take it off and try it inside because by the sounds of it its going to need to come off and be replaced anyways.
or
you could try that, maybe get an ir thermometer on it so you can try and get it close to the proper temp.
or
you could try that, maybe get an ir thermometer on it so you can try and get it close to the proper temp.
Well I tested it again today after work and with the heat on in my shed the air temp was just about or maybe even slightly above room temperature,plus I took my heat gun and aimed it at the hole in the top of the case,timing hole?,and then at the side of the recoil housing so I'm guessing some heat made it to the mag.With that done I retested the charge coil and it was closer to 1 ohm which would mean that it's getting worse with heat,and this would fall into what I'm thinking is causing the misfire I'm experiencing at higher throttle openings.The coils and the plug caps are all in spec too.