Mercruiser 3.0 No Spark issues

[alldodge]

The EST system is pretty simple. Having power to the coil when ON and while cranking, and shift interruptor disconnected. With no spark it's either the dizzy coil (was replaced), the module or ignition coil.

 

[nola mike]

Is there a flow chart for troubleshooting like for the TB systems (or points)? Any reason that you can't simulate a pulse from the dizzy pickup to the module to test?

 

[alldodge]

Is there a flow chart for troubleshooting like for the TB systems (or points)? Any reason that you can't simulate a pulse from the dizzy pickup to the module to test?

Never found one
Can make it spark by rotating the dizzy back n forth

 

[Scott06]

Is there a flow chart for troubleshooting like for the TB systems (or points)? Any reason that you can't simulate a pulse from the dizzy pickup to the module to test?

I think this is out of a VP manual but outlines how to narrow it down https://f01.justanswer.com/oldnewenglandmarine/deacd8eb-a4ca-4db4-9bec-6e9bb71197e7_Delco_EST.pdf

 

[aidanmurphy]

Thanks guys. I will test the coil today with my meter. I have reconnected the shift interrupt switch asI could not find out how to properly disconnect it. My tach is also entirely disconnected at the dash. Here is a pic of my shift switch. The right side wire goes to the terminal post that has another wire going directly to the distributor. The left side wire goes into the harness directly, I can't disconnect it. Would I simply disconnect the shift interrupt wire from the terminal post?

 

[nola mike]

My tach is also entirely disconnected at the dash.

I'd disconnect it at the coil, just to eliminate a wiring issue between the coil and dash

Would I simply disconnect the shift interrupt wire from the terminal post?

Yes

 

[aidanmurphy]

I'd disconnect it at the coil, just to eliminate a wiring issue between the coil and dash

Yes

Thank you, on my coil there is a plug with the purple power wire and the grey which I understand to be the tach/shift interrupt wire. I am not sure how I would disconnect the tach at the coil without also disconnecting the purple power wire

 

[alldodge]

Would I simply disconnect the shift interrupt wire from the terminal post?

With looking at both connectors on the dizzy, remove the one on the right. This is used for base timing and also for shift interrupt

 

[aidanmurphy]

I just tested my ignition coil and did not get any resistance readings at all on steps 3, 4, 5. Does this sound likely? I am almost positive my meter is fine, as I was getting readings when testing the pickup coil. If so, I will order a new ignition coil

 

[Scott06]

I just tested my ignition coil and did not get any resistance readings at all on steps 3, 4, 5. Does this sound likely? I am almost positive my meter is fine, as I was getting readings when testing the pickup coil. If so, I will order a new ignition coil

As long as you got a good connection when sticking in terminals b,c,f meter probes may be too fat to get a good connection to the blade terminal inside of there.

 

[aidanmurphy]

As long as you got a good connection when sticking in terminals b,c,f meter probes may be too fat to get a good connection to the blade terminal inside of there.

This is what I was concerned about. Don't want to go jamming the probes in, but can't tell if I am getting a good connection or not

 

[Scott06]

This is what I was concerned about. Don't want to go jamming the probes in, but can't tell if I am getting a good connection or not

I would verify that since you have 3 tests not getting any ohms , also I assume coil isn't shorted to ground? You didn't mention that

 

[alldodge]

I just tested my ignition coil and did not get any resistance readings at all on steps 3, 4, 5. Does this sound likely? I am almost positive my meter is fine, as I was getting readings when testing the pickup coil. If so, I will order a new ignition coil

Maybe your meter is not good. Previous test on dizzy coil showed it was bad
Use some small pieces of wire to put inside points

 

[aidanmurphy]

I would verify that since you have 3 tests not getting any ohms , also I assume coil isn't shorted to ground? You didn't mention that

I have not added a direct ground to the coil if that is what you mean, no.

 

[aidanmurphy]

Maybe your meter is not good. Previous test on dizzy coil showed it was bad
Use some small pieces of wire to put inside points

I did get a lower resistance reading on the new coil. It was hovering around 60Ohm vs the 200Ohm of the previous coil doing the same test. I will try the small pieces of wire and see if I can get any reading that way.

 

[aidanmurphy]

I just retested the ign coil with some wires sticking in and that definitely worked better. I fear my multimeter although is working may not be good enough to give me the accuracy I need. Here is a photo of it. On steps 3 and 4 on setting 10x, the needle shot all the way to the right. I don't have a 1x setting. When testing step 2, on either x1000 or x10, I cannot notice the needle moving at all, which seems to be on or close to the infinity mark. When testing step 5 using x10, the needle was hovering around the 4-5 mark on the green Ohms scale. I know I can't rely on these as I don't have the proper x1 and x100 scale on my meter. I may bite the bullet and replace the ignition coil regardless. Thoughts?

 

[alldodge]

The x1 setting is your 1K setting. While a digital is more accurate, with 3,4 you need a almost dead short (0.4 ohms) which the meter is deflecting to zero so I would say its good

Step 2 looks good

Step 5 is showing 4 to 5K ohms
Are your re-zeroing the meter for each scale prior to measuring?

Don't think the coil is the issue. I guessing its the module

 

[Scott06]

I have not added a direct ground to the coil if that is what you mean, no.

I'm not sure if you are using what alldodge posted in post # 21 or the link I sent .

In test #2 in what alldodge posted tests coil for short to ground

same test is in #1 under ignition coil test in what I posted. If coil has short to ground I would expect no spark.

Also as mentioned stick short piece of wire in there if you don't think the probes fit.

 

[Scott06]

I just retested the ign coil with some wires sticking in and that definitely worked better. I fear my multimeter although is working may not be good enough to give me the accuracy I need. Here is a photo of it. On steps 3 and 4 on setting 10x, the needle shot all the way to the right. I don't have a 1x setting. When testing step 2, on either x1000 or x10, I cannot notice the needle moving at all, which seems to be on or close to the infinity mark. When testing step 5 using x10, the needle was hovering around the 4-5 mark on the green Ohms scale. I know I can't rely on these as I don't have the proper x1 and x100 scale on my meter. I may bite the bullet and replace the ignition coil regardless. Thoughts?

Id spend $30 on a digital mutli meter vs a coil

 

[aidanmurphy]

Thanks a lot guys. I am not familiar with using a multi-meter, but after reading up on it and figuring how to zero mine I retested. Results from following the steps alldodge posted

Step 2: Needle doesn't move / infinity
Step 3: 0 Ohms
Step 4: 0 Ohms
Step 5: 8000 Ohms

The trick for step 5 was making sure it was zero out correctly. So seems like if 0 is fine for the 0.4 steps the coil is good. We have ruled out the ign coil and the pickup coil (replaced), and we have 12V at the ign coil. It appears that the manual does not have a way to test the ignition module and simply says to replace it if the other components check out. Looks like I will be sourcing one of these