Alternator not igniting question

[Cahoon520]

The alternator in my truck wont ignite till I rev the piss out of the engine. This only happens when it is cold. What could be causing this?

[Rob W.]

do you mean it's not charging when cold? It's probably the battery at least that's my guess it's the only part of the charging system affected by cold. I could be wrong but have it load tested check the electrolyte if possible.

[datzenmike]

Tighten the fan belt.

[Cahoon520]

Yes i have to rev the hell out of the engine to get the alternator light to shut off. It is a brand new battery.

[wayno]

Maybe it is the cold, you live in a freaking icebox this time of year, I wouldn't even function properly up there, when it gets below 0 degrees, the only thing I do is keep throwing wood in the woodstove. :lol:

I have no idea what is wrong, when you rev it, the light goes out, does it come back on when it returns to an idle, or does the light stay off? Do you have another alternator? As I remember now, you are running another alt. from something, is it a gas 720 alt? If it is, it shouldn't make a differance at all, so you have another one as backup?

[Rob W.]

I like the fan belt idea didn't think of that. Also anything can be defective it costs nothing to have it checked (the battery I mean) Like he said though check that belt

[Cahoon520]

Hey Wayno its realy not that cold right now its about 50 degrees. After the light goes out it charges at 14.4 or around there no problem. The belt is tight and not slipping. Iam so confused by this. Maybe it the glow plugs drawing the voltage down to much....

[DanielC]

Is this a stock Nissan/Datsun alternator?

If so, check the brushes in the alternator. they may be worn out.

[Cahoon520]

The alternator is from a gasser 720.

[wayno]

Hey Wayno its realy not that cold right now its about 50 degrees. After the light goes out it charges at 14.4 or around there no problem. The belt is tight and not slipping. Iam so confused by this. Maybe it the glow plugs drawing the voltage down to much....

 

 

I seriously doubt the glow plugs have anything to do with this, you put reset breakers in where the fusable links are supposed to be, I would check them first, make sure they are working properly, funny things happen when them wires don't work properly, things won't work when the engine is not running, but if you get it started, things get power strait from the alternator somehow, I think the DPC/glow plug timer are playing a part in this, when the engine is not running, there is no power, get that alt' turning and things start getting power from somewhere. I had an issue recently where the starter wouldn't work except if I jumped it with a screwdriver right on the starter, not even with a remote trigger, but once the engine was running, all of a sudden the starter worked, till the engine was shut down, then it wouldn't work again, lots of stuff wouldn't work unless the engine was running, turned out to be that set of fuseable links. How does the DCP module know the engine is running, unless the alt. tells it by turning/creating power, as that engine controller doesn't move till the engine starts to turn, the key seems to have nothing to do with it.

[Laecaon]

My wagon does this. But You only need to hit like 2k rpm to turn the light off. And then the light stays off. Sticky voltage regulator? Like it needs a certain voltage until it starts doing its job and then it is warm?

[albyneau]

The alternator in my truck wont ignite till I rev the piss out of the engine.

 

Try a liquid accellerant ( I prefer Kingsford) and fireplace matches~ so you don't melt knuckle hair....

[ggzilla]

Ignite is the wrong term. Excite is the term used with generators.

 

Probably sticky brushes. You can take the rear case off and clean them up.

 

I've had this happen in my Datsun.

[Cahoon520]

Oops i ment excite not ignite.