I'm trying to use a multimeter to check my coils and i can't get a good reading.. the numbers just bounce all over the damn place.. what am i doing wrong??
Checking Coils
whtpny
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What are you measuring, resistance?
If so then the primary side should be 0.3Ω to 0.8Ω, the secondary (between the + terminal at the harness connector and the HV pin at the bottom) should be 4kΩ to 10kΩ.
Make sure you are not touching the probe tips, as your body's conductivity can cause erratic readings.
If so then the primary side should be 0.3Ω to 0.8Ω, the secondary (between the + terminal at the harness connector and the HV pin at the bottom) should be 4kΩ to 10kΩ.
Make sure you are not touching the probe tips, as your body's conductivity can cause erratic readings.
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All transformers (which is what a coil is) have primary and secondary windings. The primary winding is always the input side, the secondary always the output.
In the case of the COPs on our engines the two terminals at the top, where the harness connects, are connected to the primary winding. The secondary winding has one connection in common with the positive primary terminal, the other is the high voltage terminal that connect through the suppression spring to the spark plug.
The positive primary terminal may not be marked, it is the one that the red harness wire connects to.
When measuring very low resistances (like the primary windings) you need to first touch the meter probes together solidly and make note of the meter reading. The value you see will typically be 0.1Ω to 0.3Ω, and is the base resistance of your test leads, the meter connections, and the connection between the probes.
When you measure the DUT (Device Under Test) you need to subtract the base resistance from the DUT reading. Also make sure you get solid connections between the probes and the DUT, as any resistance in the those connections will be added to the overall reading--this is the jumping about you observed.
Clamp the COP in a padded vise (gently), or have someone hold it so that you can sort of scrape the probes on the primary terminals until you get solid contacts--when you do the reading will stabilise. Remember to subtract the base resistance to get the true resistance of the DUT.
In the case of the COPs on our engines the two terminals at the top, where the harness connects, are connected to the primary winding. The secondary winding has one connection in common with the positive primary terminal, the other is the high voltage terminal that connect through the suppression spring to the spark plug.
The positive primary terminal may not be marked, it is the one that the red harness wire connects to.
When measuring very low resistances (like the primary windings) you need to first touch the meter probes together solidly and make note of the meter reading. The value you see will typically be 0.1Ω to 0.3Ω, and is the base resistance of your test leads, the meter connections, and the connection between the probes.
When you measure the DUT (Device Under Test) you need to subtract the base resistance from the DUT reading. Also make sure you get solid connections between the probes and the DUT, as any resistance in the those connections will be added to the overall reading--this is the jumping about you observed.
Clamp the COP in a padded vise (gently), or have someone hold it so that you can sort of scrape the probes on the primary terminals until you get solid contacts--when you do the reading will stabilise. Remember to subtract the base resistance to get the true resistance of the DUT.
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whats with those buttons on the side of your shifter bezel?
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Why do you need to check the coils? Are you having symptoms? I normally pull it off the plug and stick the end on my tongue to make sure its sparking when the motor is on. You'll know real quick if its working!! J/K. A quick way to give them a quick check it to unplug them one by one while watching the fuel trims on a datalogger. You will see the trim shift when you unplug it, so if the trim does not shift, that is the bad COP.
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Are you sure its a misfire? Is it at part throttle or WOT? Have you been recently tuned or checked your plugs?
it happens at idle consistently and usually when i feel it while accelerating it's during normal acceleration.. but lately i havent felt it during acceleration.. haven't been tuned yet :'( and the plugs were changed not too long ago, haven't checked them again though
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I would look for a vacuum leak, and clean the maf.
i checked for vacuum leaks back a month or two ago when i first noticed.. sprayed the stuff all over and never got a single rpm jump.. i also cleaned the maf at that time.. i was going to clean it again yesterday but found out that somehow, the 1/2 can i have of electrical contact cleaner is no longer pressurized.. so it won't spray out :mad
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alright.. i finished reading your page.. so are you thinking this could have something to do with my misfire? also.. occasionally it has trouble finding it's idle nothing too drastic.. sometimes itll bounce around 8-900 ish sometimes go as low as 6 (not in one fatal swoop, i might add.. only gradual changes when it's trying to find it) and when i observed a "consistent" idle using that HEC deal it showed that it teetered between 730-750 or so
i asked my mechanic if he thought he could find anything out but he said the only thing he could find out would be codes that are being thrown when a CEL is present.. if there is no CEL then he has to be just like us and play detective
Get another mechanic ....there is a mis-fire counter in the PCM ...the motor has to mis -fire a # of times before the code even shows . Just because it does not throw a code does not mean its ok . Put the car under a load and hold the brake you will feel it . A Sun scan machine can show you the firing voltage on a graph . Bad plug, bad coil , bad PCM, low compression ,bad fuel injector,crank shaft position sensor, can all cause this .Take to some one like a dealer before you waste money on parts.
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