Misfire on multiple cylinders

[Newcomer]

Checked and cleaned the grounds on engine block.  Checked the coil resistance.  The coil has two connectors, don't know specifically what each input does.  Each input reads about 4 ohms.  And each of these inputs has about 14v to ground when engine is running. The output (coil wire) reads about 8k to each of these input connectors.

[Harderkev]

 Ok. Mine is 8.47k from high voltage coil terminal to each of the 4 pin connectors.

 Since you've replaced the coil, I'm more interested to know what's going into the coil from the ECM. With either key on or key off (engine not running), all but the purple wire (fat wire on lower connector) on mine are neither grounded nor powered. Purple had battery voltage with key on.

Edited August 11, 2020 by Harderkev
Misunderstood measuring method.

[Steve B.]

9 hours ago, Newcomer said:

Checked and cleaned the grounds on engine block.  Checked the coil resistance.  The coil has two connectors, don't know specifically what each input does.  Each input reads about 4 ohms.  And each of these inputs has about 14v to ground when engine is running. The output (coil wire) reads about 8k to each of these input connectors.

Now, I'm going to show my lack of knowledge. But, I think one side of the coil should be ground. Does one side show +12 and the other -12?

Steve B.

[Harderkev]

Steve B.  That's where I was going with my question. I didn't realize these are not the old school coils that just have 2 terminals until I looked at mine!

[Newcomer]

On mine purple has battery voltage, just like yours.  I believe I get voltage on purple and brown to ground while running.  The brown wire is the upper black connector.

[Harderkev]

Have you investigated where these coil signal wires go and what condition the wires, connectors and attached components look like? I did not remove my ECM cover. Maybe check the individual wires for resistance values to rule out damage to the wire under the insulation?

[Steve B.]

40 minutes ago, Harderkev said:

Steve B.  That's where I was going with my question. I didn't realize these are not the old school coils that just have 2 terminals until I looked at mine!

Ya, it would be nice to understand how the ICM, ECM and coil connections and communications work. 

Steve B.

[Newcomer]

Have not dug this deep.  All wiring looks really nice and buttoned up.  I would have to cut the tyraps, remove all tape, and go into the protective sleeving.  I have looked at the ecm and removed the connectors for inspection.  All looks ok no bent pins, no moisture, or corrosion.

[justgary]

But Dorothy!  You can RTFM at any time!

https://cdn.bakesonline.com/media/resourcelibrary/Indmar_MEFI4manual.pdf

Page 5-54.

[Harderkev]

11 hours ago, justgary said:

But Dorothy!  You can RTFM at any time!

https://cdn.bakesonline.com/media/resourcelibrary/Indmar_MEFI4manual.pdf

Page 5-54.

Great resource. Thank you!

[justgary]

2 minutes ago, Harderkev said:

Great resource. Thank you!

You are welcome.  The next pages feature a complete spark troubleshooting guide, so perhaps this thread can move along for both of you.

@Newcomer, I'm suspecting your pickup coil.  You have covered everything else, but go through the steps to verify.

[Newcomer]

I can't wait to get into this.  Thanks for the support.  I have already replaced the pickup coil also, when I did the ICM, cap, rotor, wires.  What next, LOL.

[Newcomer]

Where can I find a wiring diagram for this 2001 Indmar?

[justgary]

57 minutes ago, Newcomer said:

Where can I find a wiring diagram for this 2001 Indmar?

The diagrams starting on page 8-26 aren't enough?

[Newcomer]

Oh yeah, cool. I hadn't made it that far earlier.  You da man!

[Harderkev]

Well, after completely charging both of my batteries and replacing the cap/rotor along with mundane cleaning and checking of the distributor connections, my cold misfire was gone during yesterday's outing. Fingers crossed it stays that way but I don't know what may have solved it. Highest likelihood in my mind is the battery condition followed by a cap or rotor fault.

[Newcomer]

I'm still at it and have not resolved this misfire issue yet.  I have checked and swapped everything I can think of.  I may have it down to the ECM.  I found a grounded pin from the distributor harness that grounds to the ECM.  Per the MEFI manual this pin (REF LO) should only be grounded in the ignition module and not the ECM.  Anyone know if the ECM can be bought and replaced or if it must be installed and programmed by a service center?  I don't know what else to try.  Not completely sure of the reliability of the MEFI manual since it has conflicts within.

[Steve B.]

There is a place that repairs them if they can be. I' ll post a link when I'm at the computer.

Here ya go: ECM folks

Steve B.

Edited August 29, 2020 by Steve B.

[justgary]

3 hours ago, Newcomer said:

Not completely sure of the reliability of the MEFI manual since it has conflicts within.

What conflicts?