i think i have a bad coil?

patsdsm · Nov 9, 2005

my car around 3000 rpms starts to stutter, and has no power what so ever, its runs like a car with a stutter box around 3000 and wont power out of it at all

92redman · Nov 9, 2005

So what is the question?

DSMcrazy3 · Nov 9, 2005

I think he was inadvertantly asking if it's his coil.

First you need to change plugs, and plug wires to see if that solves your problem. You can also test your coil for voltage to see if it is putting out the right amount.

You're on the right track though, usually studdering is cause by misfire, which is cause by some faulty ignition source.

92redman · Nov 9, 2005

If you wanted to test the coil unplug the coil pack connector and just take your ohm meter and measure resistance from where cyl 2 and cyl 3 ignition cables plug into the coil pack and then between 1 and 4. 2 and 3 are the two closest to the front of the car and 2 and 4 are closest to the firewall. This is secondary resistance and should be between 11.3 and 15.3 kohms.

To measure primary resistance of the coil you are going to measure where the plug connects to the coil pack. You measure between pins 1 and 3 and between 2 and 3. Pin 3 should be the one by itself at the opposite end of the locking tab. .7-.86 ohms is standard.

If your coil pack is bad, you will have misfire on two cylinders, so if it is only missing on one cylinder you should replace plugs and wires first.

talontsiboy24 · May 26, 2009

92redman said:
If you wanted to test the coil unplug the coil pack connector and just take your ohm meter and measure resistance from where cyl 2 and cyl 3 ignition cables plug into the coil pack and then between 1 and 4. 2 and 3 are the two closest to the front of the car and 2 and 4 are closest to the firewall. This is secondary resistance and should be between 11.3 and 15.3 kohms.

To measure primary resistance of the coil you are going to measure where the plug connects to the coil pack. You measure between pins 1 and 3 and between 2 and 3. Pin 3 should be the one by itself at the opposite end of the locking tab. .7-.86 ohms is standard.

If your coil pack is bad, you will have misfire on two cylinders, so if it is only missing on one cylinder you should replace plugs and wires first.

i replaced plugs and wires and i still get codes P0300 Random/Multiple Cylinder Misfire Detected and P0304 Cylinder #4 Misfire so do u think i should replace my coil pack?

92redman · May 27, 2009

Are you actually having misfiring or is it just setting faults? If it is running bad, see if somebody on here lives near you and has a good coil pack to swap. They aren't that cheap. You could have coil pack transistor problem, bad ECM or even a mechanical problem. Have you checked compression?

talontsiboy24 · Jun 2, 2009

92redman said:
Are you actually having misfiring or is it just setting faults? If it is running bad, see if somebody on here lives near you and has a good coil pack to swap. They aren't that cheap. You could have coil pack transistor problem, bad ECM or even a mechanical problem. Have you checked compression?

no i cant hear it misfiring honestly it just brings these codes up all the time so maybe my timing is off a bit?

bigf4 · Jun 5, 2009

I had that problem and bought a cop for the car. no more problem.

DeviantBoost · Dec 9, 2009

92redman said:
If you wanted to test the coil unplug the coil pack connector and just take your ohm meter and measure resistance from where cyl 2 and cyl 3 ignition cables plug into the coil pack and then between 1 and 4. 2 and 3 are the two closest to the front of the car and 2 and 4 are closest to the firewall. This is secondary resistance and should be between 11.3 and 15.3 kohms.

To measure primary resistance of the coil you are going to measure where the plug connects to the coil pack. You measure between pins 1 and 3 and between 2 and 3. Pin 3 should be the one by itself at the opposite end of the locking tab. .7-.86 ohms is standard.

If your coil pack is bad, you will have misfire on two cylinders, so if it is only missing on one cylinder you should replace plugs and wires first.

I was wondering how sensitive the primary ignition coil resistance is, I am measuring 1.3 and 1.2 ohms where it should be .7 - .8, my secondary coil is sitting nicely at 13.5 kohms. Should i replace my coil?

brownfinger · Dec 9, 2009

I had a coil that measured within all specs, but still ran like crap. I put a different, used, coil on, which did NOT measure in spec., and the car ran much better! Needless to say, I bought a new one.

patsdsm said:
my car around 3000 rpms starts to stutter, and has no power what so ever, its runs like a car with a stutter box around 3000 and wont power out of it at all

That could be an O2 sensor issue. Try a different one if you have access to one.

2GeNTSi · Jul 1, 2015

92redman said:
If you wanted to test the coil unplug the coil pack connector and just take your ohm meter and measure resistance from where cyl 2 and cyl 3 ignition cables plug into the coil pack and then between 1 and 4. 2 and 3 are the two closest to the front of the car and 2 and 4 are closest to the firewall. This is secondary resistance and should be between 11.3 and 15.3 kohms.

To measure primary resistance of the coil you are going to measure where the plug connects to the coil pack. You measure between pins 1 and 3 and between 2 and 3. Pin 3 should be the one by itself at the opposite end of the locking tab. .7-.86 ohms is standard.

If your coil pack is bad, you will have misfire on two cylinders, so if it is only missing on one cylinder you should replace plugs and wires first.

Just did this test and secondary is within spec. Primary resistance was about 2.5-3.0 for both pairs. I'm considering replacing it or finding a refurb.

I also noticed that the metal contact inside coil #3 has this kind of dirty buildup on it. All the other coils looks fine and I can see the contact easily.

442powerstroke · Jul 1, 2015

is it just one cyl or two? did you pull plug when idle

2GeNTSi · Jul 1, 2015

442powerstroke said:
is it just one cyl or two? did you pull plug when idle

It's just the #3 coil that is dirty. I did the test with the coil off the car.

luv2rallye · Jul 2, 2015

2GeNTSi said:
Primary resistance was about 2.5-3.0 for both pairs.

That sounds really bad and WAY out of spec. If you want a sure fire test to visually see how weak the spark is do this: http://www.dsmtuners.com/threads/is-this-a-ground-no-spark-issues.415723/#post-152745735. This link is for a 2g. For a 1g coil, use the yellow-black for plugs 2 & 3 and yellow-green for plugs 1 & 4.

2GeNTSi · Jul 3, 2015

luv2rallye said:
That sounds really bad and WAY out of spec. If you want a sure fire test to visually see how weak the spark is do this: http://www.dsmtuners.com/threads/is-this-a-ground-no-spark-issues.415723/#post-152745735. This link is for a 2g. For a 1g coil, use the yellow-black for plugs 2 & 3 and yellow-green for plugs 1 & 4.

Would I be able to replace just the wiring back to the coilpack connector in order to fix this or would this mean I should start looking to replace the coilpack altogether (assuming the reading is correct)?

luv2rallye · Jul 3, 2015

Sounds like you need a new coil pack.

2GeNTSi · Jul 3, 2015

luv2rallye said:
Sounds like you need a new coil pack.

Reached out to a local mitsubishi salvage yard and they have them used for $45. I'll make sure to bring my voltmeter when I go though.

Also did a test on my PTU. Without a battery hooked up pins #3 + 8 had no continuity but #1 + 3 did. I have no alligator leads right now to try it out with the battery per the Haynes manual, but I'll get one soon before I go out any buy another PTU.

luv2rallye · Jul 7, 2015

Proper PTU test: http://www.dsmtuners.com/threads/how-to-test-the-power-transistors.229419/

DSM1G90 · Jul 9, 2015

I had misfire and it was a bad power transistor. One side shorted across. Did the coil and transistor replacement and was back on the road again.

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