I just got thru changing the brushes in my Denso alternator. I posted a thread yesterday in the HELP forum asking if the brushes solder in. Well, they do. BUT if I had it to do again I would spend a few dollars more and get the brush holder with the brushes in them. I just found about that from sites that Nitrousn and Mike D told me about. (thanks). Anyway I got them changed and its charging fine. Cost 6.71 for the brushes.
When I first cranked it up it I let it idle for about 10 min and it was charging the whole time,no flucuation. I killed it and cranked it right back up and the voltage was flucuating up and down because the grid heaters were cycling. Why didn't they do that when I first cranked it up? Just exactly what do the grid heaters do? I live in South Texas where it very seldom gets colder than the 40's. Would it hurt anything to disconnect them?

 

I guess you havn't been outside lately. I live not far from you and it's 44 degrees. My truck hasnt' started since the cold front came in, it might be in your best interest to leave the grid heaters connected.

Mine fluctuates when it's running and the grid heaters come on and off.

 

Yes, I just came in the house from changing the brushes. Its 39 now but it rarely gets this cold and it won't last long!

 

I never wait for the grids unless the temp gets below 32 F. Even then I don't always have the patience to wait. Truck starts up on the first or second compression.
I am considering putting in a switch to turn off the grids so they don't keep cycling.
Jay

 

The grids are really more of an emissions thing than a starting aid. Mine had fried relays last winter, the truck started fine unplugged at 17 degrees. If you want to disable them the truck will start fine without them. And like Jay says, you don't have to wait for the light. The PCM shuts off the grids as soon as you crank the engine. That won't disable the post heat cycle, but that's the grids cycling alternately - not both at once like the pre heat. If I thought the battery was weak, I'd crank right away instead of letting the grids drain the battery worse.

BTW, I bought a pair of relays last week so the truck wouldn't be so smoky - those POD's really white smoke a lot when it's cold. An even $40 at Grainger, my donation to cleaner air.

 

I just made a page going over taking the relays apart and cleaning the contacts. Just did mine on sunday.

The link is Relay Tuneup and pre-heat/post-heat info

Den

 

Good work, Den! Unfortunately mine were melted - the hot terminal had actually pulled out of the case on one of them.

 

Yea, thanks Den.
Figures that it would be a Florida guy who never needs the heaters that would have to teach us cold climate guys how to do this

Just printed it out for a future weekend project.
Jay

 

Actually you guys need to keep that chilly weather up there. Keeps drifting down here. If I move any farther south, i'll have to live on a boat

We get the chilly mornings dipping into the mid 30's. I saw the cold front coming and decided to make sure they were going to work. My truck smokes the cold diesel haze big time with or without them on. Anything below 65 and I look like the skeeter truck

Den