STILL cannot get the 454 started.....help

PlayDate said:
I think that is the problem. I checked Sea Ray and they reference Thunderbolt Ignitions for 1983. We just finished another thread on this topic last month. Power to the coil, new sensor, cap and wires equals no start. That was what the other post was all about.

http://clubsearay.com/showthread.ph...lectronics-troubleshooting?highlight=playdate

-JD
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thanks. after reading that I might have miswired the coil. two greys at negative and two purple to positive, I think I split them up, i'll have to check. this issue has gotten even more outrageous and nerve racking buy the day since the boat is in the water and it just touched 29 degrees tonight.
 
I just went back to the beginning to see what alls been done. Start with double checking your wiring at the coil, check all the wires including from the coil to the cap. From what I've looked at (I may be very wrong here) the Thunder Bolt system controls the timing advance. When mine went bad the engine would start but not go above 1300 rpms, but that's just mine. Try not to let the weather rush you, that's how other mistakes are made.

Pull one of your plug wires and ground it with a screwdriver, see if you have a good strong spark. Start with the simple stuff, then head towards the Thunderbolt. Maybe see if someone can help you get her to your trailer and take her home to work on.
 
dwna1a said:
I just went back to the beginning to see what alls been done. Start with double checking your wiring at the coil, check all the wires including from the coil to the cap. From what I've looked at (I may be very wrong here) the Thunder Bolt system controls the timing advance. When mine went bad the engine would start but not go above 1300 rpms, but that's just mine. Try not to let the weather rush you, that's how other mistakes are made.

Pull one of your plug wires and ground it with a screwdriver, see if you have a good strong spark. Start with the simple stuff, then head towards the Thunderbolt. Maybe see if someone can help you get her to your trailer and take her home to work on.
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thanks, I went and changed out the old one with the new was only getting 10.5 volts at the coil on the new one and less than that with the old. after doing that I noticed that the part # on the box was different than the # on the bottom of the coil. thinking that I possibly solved the issue.
 
probie24 said:
thanks, I went and changed out the old one with the new was only getting 10.5 volts at the coil on the new one and less than that with the old. after doing that I noticed that the part # on the box was different than the # on the bottom of the coil. thinking that I possibly solved the issue.
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So you're thinking you have the wrong coil? Or the wrong thunderbolt?
 
Just for giggles, take ONE jumper cable and connect a negative battery terminal to the engine block somewhere. A buddy and I fought a 283 that his brother put in a Mustang for 2 days and it turned out to be a bad ground. It was a brand new engine in a cranks but no start condition.

It seems to me that if you've only got 10.5v at the coil, then you are losing between 1.5v to 3v somewhere. What is your actual battery voltage? If it's the usual 12 -13.5 volts or so, I would check the ignition switch and any solenoids in the starting circuit. If you've only got 11v at the battery, that's probably not your problem.
 
Have you used the trouble tree to check various components? You need 12v at the + coil first, use a jumper from the battery to test for spark.
If no spark follow the checklist, a bad tack (grey wire) will kill spark too.http://www.*******.com/merc/Bullet/83/83_24.pdf. replace the *`s with b,o,a,t,f,i,x no comma`s
 
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dwna1a said:
So you're thinking you have the wrong coil? Or the wrong thunderbolt?
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I'm thinking that I got the wrong part. the serial number on the part should match the number on the box right? the number on the box is the right number for the boat but the number on the part doesn't match
 
skibum said:
Just for giggles, take ONE jumper cable and connect a negative battery terminal to the engine block somewhere. A buddy and I fought a 283 that his brother put in a Mustang for 2 days and it turned out to be a bad ground. It was a brand new engine in a cranks but no start condition.

It seems to me that if you've only got 10.5v at the coil, then you are losing between 1.5v to 3v somewhere. What is your actual battery voltage? If it's the usual 12 -13.5 volts or so, I would check the ignition switch and any solenoids in the starting circuit. If you've only got 11v at the battery, that's probably not your problem.
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I got 12v at the battery. I'm thinking I got a bad ground as well but this part number thing is bugging me as well now. funny though when I search for the serial number that's on the bottom of the coil it says part not found everywhere I look
 
probie24 said:
I'm thinking that I got the wrong part. the serial number on the part should match the number on the box right? the number on the box is the right number for the boat but the number on the part doesn't match
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I think you're right! It's a good place to start. What's the number on the coil and the number on the box....morning coffee investigation time on my hands here, plus it's only 27 outside. It's hard to clean windows when the cleaner freezes
 
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number on the box is 8m0079202 and the number on the coil is 8m0065923
 
The 5923....is it marked mercruiser? The correct coil is the 9202 for your boat motor
I just ran a search on all Mercury, Mercruiser, and Mariner parts that part number doesn't show in any of them
 
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dwna1a said:
The 5923....is it marked mercruiser? The correct coil is the 9202 for your boat motor
I just ran a search on all Mercury, Mercruiser, and Mariner parts that part number doesn't show in any of them
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thanks its 9202 I took it to the shop and the guy said that the number on the coil is the manufacturers number he said he has no idea why mercruiser does it but apparently its legit. anyways with that on i'm only showing 10.5 to 11 volts on the coil. I did notice that there is a purple hot wire going from the alternator to the coil on the thunderbolt 4 diagram and that I got the puple wire attached to the alternator and from the alternator it follows a gray wire to the coil but the purple wire is cut a couple inches shy of the coil. thinking this could be the prob but I can't figure out how it would've been cut since the boat was running since sept until a few weeks ago when this fiasco started?
 
You sure it's off the alt? Not off the thunder bolt box? There should be a gray, purple, and a black ground. The purple and gray wires run between the coil and dist pickups. I will be going to my boat in the morning and I will double check things out then.
 
dwna1a said:
You sure it's off the alt? Not off the thunder bolt box? There should be a gray, purple, and a black ground. The purple and gray wires run between the coil and dist pickups. I will be going to my boat in the morning and I will double check things out then.
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ya there is a purple and gray from the box but it shows a purple and grey from the alternator as well. oh almost forgot, do you know if the water temp gauge is supposed to work when you turn the ignition on, not crank the engine but just with the key in the on position?
 
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I just read this post, do you have a Thunderbolt manual?
You should have a purple wire from the alternator to the + side of the coil with a purple wire from coil to the ignition module, it should have a gray wire from ignition module to - side of coil with a gray wire from coil going to pin #2 of the wiring harness for the tachometer signal. Manual doesn't show any gray wire on the alternator side.
Water temp should read zero with key on.
PM me your email address if you need a manual.
 
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Bob & Sue said:
I just read this post, do you have a Thunderbolt manual?
You should have a purple wire from the alternator to the + side of the coil with a purple wire from coil to the ignition module, it should have a gray wire from ignition module to - side of coil with a gray wire from coil going to pin #2 of the wiring harness for the tachometer signal. Manual doesn't show any gray wire on the alternator side.
Water temp should read zero with key on.
PM me your email address if you need a manual.
Click to expand...
I pulled up the wiring diagram for the thunderbolt 4 online and it shows a purple wire and a gray wire going from the alternator to the coil with purple on + and gray on the - it also shows a purple and gray wire going from ignition module to the coil as well. the purple wire from the alternator is severed up by the coil on mine. I do have a wire from the coil to the tach. and water temp is good then thanks. do you know if the neutral safety switch will allow you crank the engine if it needs to be replaced? most people say no but the guy at the marine shop says that is not necessarily true- he said it can just not allow a spark. mind boggling right now
 
The neutral safety switch depends upon the transmission design and whether or not the engine manufacturer sold the engine/transmission as a unit and did the electrical design or if the neutral safety switch was part of the controls installed by the boat builder. Either way, you are going to have to find it and trace the circuit. Here is a start......if it is on the transmission, it looks like a brake light switch on a car and is on the shift housing on a BW if you have a BW gear coupled to the TRS drive.
 
Ok, on mine. If the switch is tripped (in gear) the engine will not turn over. I wiggle the shifter and she will start (turn over)

Might be time to call in a pro.....it's gonna be something silly
 
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