Alternator Intermittent

[torqueluvr]

Hi all,

Sometimes when I start my truck my alternator doesn't kick in for seconds, minutes. The voltmeter will be below 1/2 on the dash, and signal lights won't work. After driving for a couple minutes they come back on. This has happened to me twice in 3 weeks, in which I have driven the truck probably 10 times.

Any guesses? Alternator? Relays?

BJ74 13B-T JDM 24V.

 

[torqueluvr]

bump for some potentially serious alternator problems.

 

[Urbancarrot]

bump for some potentially serious alternator problems.

I bet your batteries need replacing. Now that it is around zero outside battery problems start to show up.

I just replaced my two batteries. When I took a volt meter to each battery they had plenty of juice and my alternator was charging fine. However, once the batteries were tested under load they were done.

Replace both batteries.

 

[Radd Cruisers]

Brushes...

Check them for protrusion length.

Also, when the glow screen is running you will see fairly low volts on the gauge - it draws huge amps. The glow screen will turn off in anywhere from about 30 seconds to a couple of minutes, at which time the volts should slowly recover as the batteries take a charge.

You need healthy batteries - as big as you can fit.

~John

 

[torqueluvr]

Thanks guys. I just installed a Wilson Switch for the glowscreen, so maybe that has something to do with it. I will check the batteries and brushes on monday. Hopefully I can do the brushes without removing the alternator...

 

[torqueluvr]

So I got Interstate Batteries to test my Napa batteries and they are good. My alternator, when it charges, puts out 30.1V - seems healthy.

I am now losing battery power over night. When I park my truck for two nights, in the garage, I go to start it after using the glowscreen for about 8 seconds - wilson override switch - my cranking is really low. It seems I am losing power while it is parked. Dan at 4 wheel auto said I have extensive draw on something - would this be my new lights and wilson switch? They're all turned off when the truck is off so I don't think it would pull any extensive draw.

In conclusion, I am experiencing low battery power when starting the truck after being parked for two days AND it takes ~30 seconds for the alternator to charge after start up.

So, still new brushes? Can I do this with the alternator in the truck? Are my new accessories really pulling that much draw?

TP

 

[Ron R]

My advise would be to get the alternator checked.
The voltage is too high in my opinion.
Probably the brushes like Radd Cruisers says, but one of the diodes could be shot as well.

 

[Gun Runner 5]

Deleted.......

 

[torqueluvr]

Thanks fellas. I was trying the cheapest options first as noted many times in this forum before. I'll get the alternator tested to see whats going on - that should cover diodes and voltage regulator. Then I'll check the brushes.

Thanks again. As always I will post the results for future forum searchers.

Stay tuned.

 

[BTC95]

It is normal in my experience for the alternator to take 30 seconds or so before it starts charging. My BJ74 has always been like this.

 

[ducatiman81211]

BJ74 alternator/charge gauge

My 74 did the same thing until I moved to where it is never necessary to pre-heat, so I disconnected the system; now the alternator gauge never moves away from the normal position as it's not using the energy anymore. So as stated before; it's normal. I would replace the batteries.

 

[Radd Cruisers]

It is normal in my experience for the alternator to take 30 seconds or so before it starts charging. My BJ74 has always been like this.

The alternator is working immediately, what you are seeing a low voltage situation due to the glow system being on.

~John

 

[torqueluvr]

Turns out the batteries and alternator were fine. When I installed the wilson switch I drained the batteries when testing the glowscreen system. A 200km roadtrip charged the batteries great, and after sitting for 3 days it starts up great. Thanks for all the help.