Old 05-28-2024, 05:21 PM
ponchjoe's Avatar
ponchjoe ponchjoe is offline
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Default Can anyone tell me what this is for?

Hi guys,

My brotherís 74 GT has a crank, no start issue and I will be starting to diagnose it for him tonight. Iím going to look at neutral safety and module type issues but what is this fuse holder for that appears to go to the HEI?
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Old 05-28-2024, 06:43 PM
unruhjonny's Avatar
unruhjonny unruhjonny is offline
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unless I am mistaken the fuse links were in the charging system - but I am more familiar with those pesky parts on a 1973 engine.

1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.

1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)
Old 05-28-2024, 09:26 PM
Held for Ransom's Avatar
Held for Ransom Held for Ransom is offline
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That looks like the tach wire.

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Old 05-30-2024, 11:21 AM
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fiedlerh fiedlerh is offline
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Join Date: Feb 2002
Location: Illinois
Posts: 2,258

The brown wire is the signal for the tachometer off of the coil negative. It has an inline fuse to protect the tachometer, I seem to remember it's a pretty low value like 2 amp.

Common failures that cause a no start on an HEI:
A loose or corroded connection.
Coil pickup wires broken. (fairly common)
Bad HEI module. Common with no-name after market modules. Try to use the original GM "990" module.

Link to the HEI manual: http://www.pontiacpower.org/HEI.pdf

BTW, later production 1974's got HEI from the factory.

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