Apha One V6, Thunderbolt IV

[rodbolt]

Re: Apha One V6, Thunderbolt IV

the HEI was NEVER marinized and NEVER had a full mechanical advance.
ALL used a mechanical AND a vacum advance.
the EST however was marinized AND uses a fully electronic advance.
the EST is a simple and cheap swap if the ICM on the T bolt ign has failed.
however if your getting spark from the coil the ign produceing components are working.
do a forum search on a home made spark tester, then make one.

 

[davebuc]

Re: Apha One V6, Thunderbolt IV

I have a similar issue. It follows a reassembly of a Mercruiser 5.7 with new heads (distributor has to come out to remove intake manifold)

I have used the Troubleshooting Thunderbolt IV ignition Flowchart (thank you, very helpful).
With it, I concluded my Distributor Ignition Sensor was bad. I replaced it, started right up in driveway. I put the boat in the lake and ran it 25 minutes with the new ignition sensor. Later in these 25 minutes I had a popping sound coming out the carburetor. I believed I could track down the cylinder creating the popping by unplugging the spark plug wires from the top of the Distributor Cap one at a time. I got it on my first guess by unplugging #2 cyl plug wire. When I unplugged it, the popping stopped immediately. Within 15 seconds of unplugging the wire, the engine stalled. It would not turn over following the stall.

I notice when I crank the engine by turning the ign key that sparks jump from the top of the coil to the negative post on the ignition coil.

I followed the ignition system troubleshooting flowchart, which indicates I have to replace the ignition sensor in the distributor again.

Did I fry the sensor by unplugging the plug wire from the top of the cap?

If not, it seems like I have a bad plug wire?
or the wire that goes from coil to cap?
Or is the rotor shorting to the shaft in the distributor?
It fits tightly and does not contact the sensor as it rotates.

All of these components are new:
Ignition Coil
Distributor Cap
Rotor
Spark Plugs

 

[ussoldier_1984]

Re: Apha One V6, Thunderbolt IV

I have the same Issue with my boat its a 95 vortec 4.3 thunderbolt IV. I went through all the steps and replaced the entire ignition system. still after about 30 mins give or take it would pop back and hesitate and die on me. Its the ignition module its bad. its heating up and breaking up causing the poping and runing like crap. replace the ignition sensor and you will be golden!!!

Only issue for me is where can I find one for less then 300 bucks haha

 

[grandpaking]

Re: Apha One V6, Thunderbolt IV

I have connected the distributor end of the coil wire to a timing light and when I turn the engine over I get an erratic display of light as though the coil is firing but not sequentially; like it would fire two or three times in a row then skip a beat and fire again! When I put everything back together I still do not get spark coming out of the distributor. I have even put the old rotor back and get the same results. Is there another ignition system I can change to that would be more reliable and less costly?

 

[dubs283]

Re: Apha One V6, Thunderbolt IV

a timing light is not a spark tester, you need an actual spark tester to check for spark coming from the coil

have you connected the ground for the ignition module to the same stud on the engine block as the negative battery cable??

when you say you put everything back together, what does this mean?? i would guess that if you are using a timing light to check for spark on the coil wire, everything should be connected as to run the engine

 

[davebuc]

Re: Apha One V6, Thunderbolt IV

>ignition module and distributor ignition sensor grounded to the same post on the riser.

This may be part of my problem, they are not on the same post.

Is it better for the ring connectors to be installed right up against the riser, (between it and the plastic spacer) OR grounded on the plate to which the ignition control module is mounted (which is separated from the riser by 1/2" spacer)?

 

[dubs283]

Re: Apha One V6, Thunderbolt IV

dave:

i was asking grandpaking about the issue with his set-up - he was the one to start this thread

if you have a question concerning your own rig, you MUST start your own thread

it is considered rude to "hijack" another persons thread with questions about your own issues - not to mention confusing to the OP and others reading the thread

 

[grandpaking]

Re: Apha One V6, Thunderbolt IV

After two months of blood, sweat, and tears the engine is back in service! Let me give you a recap: After running for 45 - 60 minutes the engine would begin to surge. I had this same problem two years before and solved it by replacing the coil. I replaced the coil and then I couldn't even start it! So, I used the diagnostics chart to find the problem. After having replaced the coil, coil wire, distributor cap, rotor, and sendor unit I still could not get spark to the plugs. Friday night I decided to start over. I took out the new coil and replaced it with the old one - WHAM! I am in business. The store that sold me the coil will not replace it. He claims I damaged it. Thanks to everyone for their help.

 

[grandpaking]

Re: Apha One V6, Thunderbolt IV

I attempted to post an update a week ago to close this issue. The trouble was I was sold a bad coil. I kept asking how I could test the output and nobody gave me an answer. In desperation I replaced the new coil with an old coil and the engine is running fine! After a lot of hassle the dealer has replaced the coil and it works! End of story. Thanks to everyone for their help.