1990 454 mag lost power
10-22-2022, 04:25 PM
#41
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10-22-2022, 04:54 PM
#42
Just for quick test to make sure ignition switch is bad, hook purple to the battery terminal (b or batt) keeping the wire hooked to it, still hooked to it and start motor. If it runs, you have bad ignition switch, which it seems like due to your checking switch positions with multimeter.
Note: engine won’t shut off with purple wire hooked to battery power. You’ll have to unhook purple from it to kill the engine.
i have a 12-14 gauge wire with alligator clips to jump terminals for such things. Makes it fadter to diagnose, especially in cramped quarters.
Note: engine won’t shut off with purple wire hooked to battery power. You’ll have to unhook purple from it to kill the engine.
i have a 12-14 gauge wire with alligator clips to jump terminals for such things. Makes it fadter to diagnose, especially in cramped quarters.
Last edited by Prestigeworldwideee; 10-22-2022 at 05:07 PM.
10-22-2022, 05:12 PM
#43
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Okay.
Throw 1st multimeter in trash.
Throw 1st multimeter in trash.
The following 2 users liked this post by SB:
Prestigeworldwideee (10-22-2022), Shotgunn (10-23-2022)
10-22-2022, 05:16 PM
#44
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Key in run position.
check for voltage on white wire w/red stripe wire going into back of distributor. What do you get for voltage reading ?
check for voltage on white wire w/red stripe wire going into back of distributor. What do you get for voltage reading ?
10-22-2022, 06:00 PM
#45
10-22-2022, 06:22 PM
#46
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Hmmm.
I know flowchart says 1-12volts, but i think it should be at 12 volts.
can you take white/red off back off dist an check that wire lead again without it touching dist term or anything but your multimeter ? Be careful with the nut - they are small and easy to drop.
I know flowchart says 1-12volts, but i think it should be at 12 volts.
can you take white/red off back off dist an check that wire lead again without it touching dist term or anything but your multimeter ? Be careful with the nut - they are small and easy to drop.
10-22-2022, 06:34 PM
#47
10-22-2022, 06:39 PM
#48
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Quick question - you have a 1990 boat. In 88 and 89 many boats had a magnum 454 with alpha drive. Any chance your boat the same ?
10-23-2022, 10:22 AM
#49
Good call on disconnecting the wire, it has 12v at the wire. When the wire is connected now, I’m barely getting a volt reading.
Last edited by Prestigeworldwideee; 10-23-2022 at 10:50 AM.
10-24-2022, 07:40 AM
#50
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So, this is typical comments with suggested diagnostics:
“if there is No voltage present at white/red wire, disconnect the white/red wire and check it again for 12 volts. If 12 volts is present, replace the ignition sensor inside the dist. cap. If no 12 volts present w/it disconnected--ignition amplifier is faulty and must be replaced.”
I have not run into a low volt issue with distributor sensors, just zero volts. Fyi: i’ve only run into three bad dist sensors, so i don’t have much good data on readings with failed units.
“if there is No voltage present at white/red wire, disconnect the white/red wire and check it again for 12 volts. If 12 volts is present, replace the ignition sensor inside the dist. cap. If no 12 volts present w/it disconnected--ignition amplifier is faulty and must be replaced.”
I have not run into a low volt issue with distributor sensors, just zero volts. Fyi: i’ve only run into three bad dist sensors, so i don’t have much good data on readings with failed units.
Last edited by SB; 10-24-2022 at 07:48 AM.
