Visit our Twitter feed for more great content
TRExp

TR6 Tech Forum

'76 TR6 Alternator Upgrade

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

smaceng Avatar
smaceng Scott Macdonald
Martinez, CA, USA   USA
Make sure the ignition warning light is hooked up and working and is NOT an LED.
Scott in CA

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Mikerla Avatar
Mikerla Gold Member Mike Ruoppoli
Pineville, LA, USA   USA
In reply to # 1595451 by smaceng Make sure the ignition warning light is hooked up and working and is NOT an LED.
Scott in CA

Why not an led?



Thanks,

Mike

72 TR6 - in the process of frame off resto
Planned:
HDVA conversion with R200 and RG's CVC axles
Miata seats

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Some alternators rely on the current through the dash lamp to "tickle" them at startup. Since LED bulbs draw much less current than incandescent ones do, using an LED bulb makes it harder for such alternators to get started. The red light may not go out until the engine is revved fairly high or not go out at all.

One solution is to add a resistor across the lamp, so the alternator gets the necessary current even with an LED bulb (or a burned out incandescent bulb).

In reply to # 1595508 by Mikerla
In reply to # 1595451 by smaceng Make sure the ignition warning light is hooked up and working and is NOT an LED.
Scott in CA

Why not an led?



Randall
56 TR3 TS13571L Once and future daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
smaceng Avatar
smaceng Scott Macdonald
Martinez, CA, USA   USA
Why not an LED? So this is my experience. I had put in one of the "Fiesta" alternators last year during my restoration. Works fine. Recently I decided to put in LEDs in the dash because I could not see the turn indicator light and the gauges were dim at night. In go the LEDs.
So soon there after, I realize that the ignition light stayed on and the alternator gauge was reading low. Well, because I had not gotten my two brain cells connected, I then took the alternator off and had it tested. And it tested fine. Then the other brain cell started working again, and I realize that the alternator "failure" occurred immediately after I installed the LED for the ignition light. So I replaced the LED ignition light with a standard incandescent bulb, and wonder of wonders, the battery is charging and the ignition light works normally.

So why? So some if not all alternators need battery voltage to excite the field windings to allow the alternator to begin producing current. So the field coils are connected through the brown/yellow wire to the ignition light. When the ignition switch is turned "ON", before the engine starts, the battery provides 12V. to the ignition light. The ignition light turns on, and the field coils in the alternator are energized. When the alternator starts to turn over, it now produces voltage. The ignition light goes out because alternator voltage is present on both sides of the ignition light.

So why doesn't an LED work. Some may, but not mine. An LED light is polarity sensitive, i.e. , it only turns on with battery voltage in one direction. If you reverse the leads, it does not light.


Does all that make sense?
Cheers, Scott in CA

LFMTR4 Avatar
LFMTR4 Lou Mijares
Scottsboro, AL, USA   USA
Drew,

Have you. He led the bulb to make sure its good and has good contacts?

Mikerla Avatar
Mikerla Gold Member Mike Ruoppoli
Pineville, LA, USA   USA
10-4 didn't realize the way the circuit worked. Makes total sense...

In reply to # 1595540 by smaceng Why not an LED? So this is my experience. I had put in one of the "Fiesta" alternators last year during my restoration. Works fine. Recently I decided to put in LEDs in the dash because I could not see the turn indicator light and the gauges were dim at night. In go the LEDs.
So soon there after, I realize that the ignition light stayed on and the alternator gauge was reading low. Well, because I had not gotten my two brain cells connected, I then took the alternator off and had it tested. And it tested fine. Then the other brain cell started working again, and I realize that the alternator "failure" occurred immediately after I installed the LED for the ignition light. So I replaced the LED ignition light with a standard incandescent bulb, and wonder of wonders, the battery is charging and the ignition light works normally.

So why? So some if not all alternators need battery voltage to excite the field windings to allow the alternator to begin producing current. So the field coils are connected through the brown/yellow wire to the ignition light. When the ignition switch is turned "ON", before the engine starts, the battery provides 12V. to the ignition light. The ignition light turns on, and the field coils in the alternator are energized. When the alternator starts to turn over, it now produces voltage. The ignition light goes out because alternator voltage is present on both sides of the ignition light.

So why doesn't an LED work. Some may, but not mine. An LED light is polarity sensitive, i.e. , it only turns on with battery voltage in one direction. If you reverse the leads, it does not light.


Does all that make sense?
Cheers, Scott in CA



Thanks,

Mike

72 TR6 - in the process of frame off resto
Planned:
HDVA conversion with R200 and RG's CVC axles
Miata seats

drewstr6 Avatar
drewstr6 Silver Member Drew Baker
Greensboro, NC, USA   USA
1976 Triumph TR6 "Drewstr6"
I did confirm that the bulb is good and I cleaned the contact really well to make sure the connection was good. I was hoping someone with a '75 or '76 could confirm how they wired their upgraded alternator. I tried to follow Dan Masters diagram, but it seems that some people leave the smaller brown wire tied off and don't hook it up at all - and the warning light still works. I've tried both ways without success.

smaceng Avatar
smaceng Scott Macdonald
Martinez, CA, USA   USA
I have a 1975 wiring loom and the smaller brown wire is not used.
Scott in CA

drewstr6 Avatar
drewstr6 Silver Member Drew Baker
Greensboro, NC, USA   USA
1976 Triumph TR6 "Drewstr6"
Thanks Scott. I guess I may have another problem if that is the case. I did some slight wiring modifications when I installed the Patton TBI system. Hopefully, I didn't mess something up that is causing the issue with the ignition warning light

drewstr6 Avatar
drewstr6 Silver Member Drew Baker
Greensboro, NC, USA   USA
1976 Triumph TR6 "Drewstr6"
I just had a thought - went out to the garage and hooked the old alternator back up to see if the light would come on with the ignition turned on. It did. So, I know the light works and since it isn't an LED, it should work with the new alternator. I was trying to do the alternator upgrade because I was trying to do a datalogging session with my car so that I could dial in everything with the new TBI install. The data showed that it was running basically on battery power only. I replaced the alternator and it is still showing the same thing.


Attachments:
old alternator.jpg    56.5 KB
old alternator.jpg

ign light to old alternator.jpg    34.3 KB
Sign In or Register to view this photo
LFMTR4 Avatar
LFMTR4 Lou Mijares
Scottsboro, AL, USA   USA
It’s the brown yellow that’s used for the light. You might want to check continuity from one side of the lamp to the brown yellow at the alternator and the other side to the green fuse

drewstr6 Avatar
drewstr6 Silver Member Drew Baker
Greensboro, NC, USA   USA
1976 Triumph TR6 "Drewstr6"
Eureka - just figured it out. I tied off the smaller brown as Scott indicated and wired it as below. Ignition Light comes on perfectly and hopefully this will solve the charging issue. Thank you all for your help. Drew


Attachments:
new alt correctly wired.jpg    38.9 KB
new alt correctly wired.jpg

ripvwsss Dennis B
Forest, VA, USA   USA
Drew,

I posted a complete writeup with pictures on August 22nd that you might want to take a look at (it is actually two separate postes due to file size limitations). This was after I successfully installed the alternator that I got from Rock Auto and it all works great now. I didn't have to use the small brown wire at all. That is because the alternator that I bought has a built in voltage sensor and that is what the small brown wire does. I tried it separately with each one connected and both worked but I decided to stick with the one that came on the alternator.


In any case, there is only two wires that go to the master plug on the alternator - the large brown one and the smaller striped one. The solid brown one is either not used or it is plugged into the connector where your black wire is now connected.


Hope this helps.

Dennis

drewstr6 Avatar
drewstr6 Silver Member Drew Baker
Greensboro, NC, USA   USA
1976 Triumph TR6 "Drewstr6"
Thanks Dennis. I looked up your post and it helped me to fix the wiring issue. I appreciate you letting me know. The ignition light is now working correctly and it appears to be charging correctly now.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster