2000 Regal 2100 LSR 5.0 No start after rebuild.

THester00

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Aug 24, 2023
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Hey all, I have a 2000 Regal 2100 LSR 5.0. the boat ran great, but the block was cracked from the previous owner forgot to winterize it, so I got it for a steal. So long story short I removed the engine completely tore it down rebuild it new block, cam, crank, pistons etc. re installed it set timing on it. TDC on one on compression stroke. Yes, cam and crank are timed. Overhead adjusted but.... I can't get this dang thing to start. My timing light will randomly light up every now and then. and when it does flash like 3 times maybe the timing light is right at the TDC mark with my light pickup wire 1. I have removed tach wires checked power at ignition coil with key on, kill switch off and on it goes from a ground to power with kill switch and key. So, I am getting signal to my coil 9.6v. I have cleaned the rotor cap contacts just to be double sure. I have checked all my grounds 10 times. Something is killing the spark in this system, and I can't for the life of me figure it out. I am 10 hours deep trying to get my rebuilt engine to start and it is frustrating is an understatement. If anyone has a pic or wire diagram of the engine and or back of the instrument cluster so I can confirm this thing is wired right that would be awesome! The thing is it ran perfect before I pulled the engine, it just leaked water out the block because it was cracked. Something has happened to it while it sat for 3 months for me to finish the rebuild any way any help would be awesome. I am a diesel mech by trade for 10 years, and pretty good with electrical, but this boat has been humbling me quick. Thanks in advance!! Another note the blower and bilge pump aren't working now so don't know if that would have to do with any of it....
 

alldodge

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Welcome
Lets start with the original motor serial number?
If you don't know the SN tell us more about the 5.0, is it fuel injected or carb? Which ignition?

kill switch off and on it goes from a ground to power with kill switch and key. So, I am getting signal to my coil 9.6v.
Kill switch should not go to ground, it should be placed inline with the purple wire coming from the key. Should pass power to the coil when closed and remove power when open.

Should also have more then 9.6V
 

THester00

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Aug 24, 2023
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Sorry that’s what I meant, when I have my meter on the coil pos and toggle the switch it goes from O.l to power. I am going to check the gray wire on the tach I believe it is supposed to be grounded and I read somewhere that you have to ground a purple and white white when you time these systems don’t know if that is accurate.
 

alldodge

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If the gray Tach wire should not be grounded. Ifthe Tach shorts out or the gray wire is grounded it will kill the spark. Disconnect the wire to take it out of the equation

If you have a purple/white wire this would mean you have a TBV ignition.
TBV Troubleshooting.jpg
 

THester00

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Aug 24, 2023
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If the gray Tach wire should not be grounded. Ifthe Tach shorts out or the gray wire is grounded it will kill the spark. Disconnect the wire to take it out of the equation

If you have a purple/white wire this would mean you have a TBV ignition.
View attachment 388112
I’m not getting spark when grounding green and white wire going to buy another coil then will update
 

alldodge

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It's usually never the coil, but the White/Green wire needs to be tapped on a good ground really fast to verify
 

THester00

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Aug 24, 2023
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It's usually never the coil, but the White/Green wire needs to be tapped on a good ground really fast to verify
Yea I used my power probe to ground really fast the coil was super hot too, my cj7 did that and was the coil worth a shot I guess
 

dubs283

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Jul 27, 2005
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Power probe to affix ground is iffy

Use a jumper wire to repeatedly strike ground on the wht/grn wire from the module

This is electricity ignition, forget your diesel complacency
 

THester00

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Aug 24, 2023
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Low and behold I figure it out 20 hours later I unplugged the nuetral switch and the motor fired right up. I guess that kills the fire all together I guess it’s shorted inside of it
 

THester00

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Aug 24, 2023
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Does anyone know the part number on a 98,99 mercruiser 5.0 belt I am having hard time finding it on-line.
 
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