79 Tachometer erratic voltage regulator output question
Thread Starter
Le Mans Master
Joined: Jun 2019
Posts: 7,658
Likes: 2,470
From: Indiana
I reran voltage drop with positive bat post to alternator big red running accessories on..
i used multimeter not pp
0.24 vdc recorded..
i noted that there is a 4 th black wire on alternator that looks like feeds ground for front lights..
thank you
i used multimeter not pp
0.24 vdc recorded..
i noted that there is a 4 th black wire on alternator that looks like feeds ground for front lights..
thank you
Racer
Joined: Jan 2020
Posts: 470
Likes: 147
From: Va.Beach Va.
Positive drop test would be in order now. Move your lead to the positive side of the battery. The Running test will be same type of test except the other lead will be on the output of the alternator. The cranking test will be on those same two points. Now you can go the gauge fuse with the positive meter lead and see what happens there in the crank test.
Thread Starter
Le Mans Master
Joined: Jun 2019
Posts: 7,658
Likes: 2,470
From: Indiana
Positive drop test would be in order now. Move your lead to the positive side of the battery. The Running test will be same type of test except the other lead will be on the output of the alternator. The cranking test will be on those same two points. Now you can go the gauge fuse with the positive meter lead and see what happens there in the crank test.
Cranking fans on
bat pos to alt..0.48
bat pos to fuse panel ign 0.68
Last edited by interpon; Jun 14, 2020 at 04:19 PM.
Thread Starter
Le Mans Master
Joined: Jun 2019
Posts: 7,658
Likes: 2,470
From: Indiana
0.24 running with accessories on to alternator big red
0.28 bat pos to ign fuse panel..interesting when i increase rpm as i was laying there..it goes to zero then slightly negative0.01..
both accessories on headlights defog
0.28 bat pos to ign fuse panel..interesting when i increase rpm as i was laying there..it goes to zero then slightly negative0.01..
both accessories on headlights defog
Last edited by interpon; Jun 14, 2020 at 06:06 PM.
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Thread Starter
Le Mans Master
Joined: Jun 2019
Posts: 7,658
Likes: 2,470
From: Indiana
x2 willcox replacement he triple checked after voltage spike knocked out first one..he was kind to me
https://willcoxcorvette.com/corvette...78-79-usa-made
check put the board on post 999 and 1004 gm article
https://www.corvetteforum.com/forums...espond-50.html
https://willcoxcorvette.com/corvette...78-79-usa-made
check put the board on post 999 and 1004 gm article
https://www.corvetteforum.com/forums...espond-50.html
Last edited by interpon; Jun 14, 2020 at 07:35 PM.
Thread Starter
Le Mans Master
Joined: Jun 2019
Posts: 7,658
Likes: 2,470
From: Indiana
I think the board already has resistors..here is a video that is interesting...
note mine issmooth when running except once in a while slight wiggle at idle..but motion similiar to this video but worse..
And for whayever reason tach accurate at idle until earmed up then idle reads ~400 rpm low but accurate at speed...weird
https://www.google.com/search?ei=YrT...HwbkP5_-80AU29
note mine issmooth when running except once in a while slight wiggle at idle..but motion similiar to this video but worse..
And for whayever reason tach accurate at idle until earmed up then idle reads ~400 rpm low but accurate at speed...weird
https://www.google.com/search?ei=YrT...HwbkP5_-80AU29
Last edited by interpon; Jun 14, 2020 at 07:43 PM.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
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There is always the nuclear option. Funniest ad ever.
https://www.corvetteforum.com/forums...-7800-obo.html
https://www.corvetteforum.com/forums...-7800-obo.html
Racer
Joined: Jan 2020
Posts: 470
Likes: 147
From: Va.Beach Va.
The next direction would be disconnecting the white wire (tach) at the Hei and start /run the engine and look at the tach. On visuals, is the white wire next to any plug wires? If so reroute it clear of them.