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98 454 mag mpi starting issue

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Old 10-28-2021 | 09:53 PM
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Default 98 454 mag mpi starting issue

I’ve been chasing this gremlin around all year long and finally need some advice….

I have narrowed it down to the circuit breaker box on top of he motor has a click when you hit the key. It feels like the Mercathode box is clicking. It would work great a few times out then you’d have to hit the key a few times with the click. I have replaced batteries, the solenoid in the box that looks like the trim one, checked connections, and tested all connections with a light. I’m stumped and hope someone can help out here!
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Old 10-28-2021 | 11:24 PM
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Starting issue is no crank ?
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Old 10-29-2021 | 05:22 AM
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Originally Posted by SB
Starting issue is no crank ?
it would click time to time but always fire up. Sounds like a starter but it’s not clicking on the starter or solenoid it’s in the box where the main circuit breaker is. Now just a click and nothing after
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Old 10-29-2021 | 07:27 AM
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Look in the box to see if you see the slave relay (can be one of 2 types). That is used to apply power to the starter solenoid


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Old 10-29-2021 | 07:39 AM
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[QUOTE=AllDodge;4810701]Look in the box to see if you see the slave relay (can be one of 2 types). That is used to apply power to the starter solenoid

I have replaced that twice, seems to me like it’s clicking from the mercathode box. I’m unfamiliar with that system and maybe it’s another box relay in there. Didn’t know if anyone had this issue before or what I should look for/at.
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Old 10-29-2021 | 08:02 AM
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Originally Posted by Rde787

I have replaced that twice, seems to me like it’s clicking from the mercathode box. I’m unfamiliar with that system and maybe it’s another box relay in there. Didn’t know if anyone had this issue before or what I should look for/at.
Could be you need to clean connections. Corrosion on a connection will not pass full voltage. Use a voltmeter and see what the voltages are prior to starting and while trying to. If voltage drops much at all then its corrosion or need a larger battery.
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Old 10-29-2021 | 08:10 AM
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Start circuit
Corrosion anywhere along the line can cause the issue



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Old 10-29-2021 | 08:52 AM
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Originally Posted by AllDodge
Could be you need to clean connections. Corrosion on a connection will not pass full voltage. Use a voltmeter and see what the voltages are prior to starting and while trying to. If voltage drops much at all then its corrosion or need a larger battery.
ok, thanks! That’s where I was headed next with it. Has 2 new 1000 cca batteries in it. I’d think that’s plenty for a single 454 but who knows electric isn’t my forte and that’s why I’m here asking lol
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Old 10-29-2021 | 09:27 AM
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$10 the click from mercathode is actually from remote solenoid which is right next to it.

When it clicks (not starting) connect big posts of relay with screw driver or ? and see if cranks. If it does, it’s typically the starter relay or it’s ground or wire connections. If it doesn’t it’s typically the starter or it’s wire connections.
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Old 10-29-2021 | 11:17 AM
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Get a test light which any big box auto parts store should have which would make it easier to check your issue?
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