Alternator output amps

[gtwitch]

I am trying to rebuild the alternator (Denso) on my 99- 2500 and need a Diode holder plate and cannot find a replacement number, What is the output amps?? 136 amps I think! Having trouble with starting and have had the batteries deep cycle checked independent of each other and tech tell me batteries check out fine, I have cleaned and checked all primary wiring and grounds. I put my spare alternator on after having it checked OK as the alternator on the truck checked out "bad diode". Now I am still looking for the hard starting gremlin. Have not checked the starting current, but the engine is turning over slow. I am leaning towards a starter, as it has 130 K on since I repaired and put the Lary B solenoid kit on at 110 K miles. Observation on my part here , I park on small (not steep) hill with cold engine (40* F) in morning, short coast to bump start in 3rd gear and engine fires instantly, Drive around block and park, five min later, starter cranks slowly and engine starts after 20 or more seconds of cranking. Plenum heaters working fine, also. Any conversation here will be appreciated!
gtwitch in wyoming

 

[fest3er]

IIRC, I had the original starter in my '98 for nigh on 300k miles; I replaced the contacts with Larry B's once. It's possible your starter is geriatric or the contacts need replacing again. Yes, my starter was finally turning somewhat slowly, slow enough to allow the block to absorb most of the heat of compression even in the mild temps here in SW VA, causing delayed starting. The new/rebuilt starter I installed cranked the engine over right smartly and it would start instantly.

Ensure the batteries are fully charged first. Test results will be skewed if they are fully up.

When you drive around the block do you exceed about 18 MPH (which turns off the grid heaters)? Each heater draws 100A. You might unplug one control lead to each heater relay and check again. There's a small chance you don't give the system a chance to recharge the batteries (that is, the batteries might not be fully charged in the first place).

Check all of the electrical connections and wires. A connection with just a few ohms of resistance can turn into a large voltage drop when lots of current is drawn across it.

Measure the battery voltage (explicitly post to post) before and while cranking. If there's little drop, I'd suspect bad connections or a failing starter. If the voltage (between starter + and battery neg. post) at the starter drops a lot, you'll have a stronger clue. Add a jumper cable clamp between the engine and the battery neg. post; this could yield a clue. Same between battery + and starter +.

In short, verify you have good connections from B+ to the starter and from the starter frame to engine, and engine to B-. If the connections are all good and the batteries are fully charged, rebuild/replace the starter.

 

[gtwitch]

Thanks fest, I'll do a little more testing with jumpers where you suggest, another clue after I replaced the alternator with my spare (tested) alternator and I return after a 120 mile trip on the highway , so batteries are at 14.2+ running and approx 12.8 to 13 after sitting, the cranking speed is slightly faster than cold 40*to 50 * start and the start will happen but still starting is hampered/delayed. My battery voltage tests are always post to post. Yes , I do get to the 18mph around block and I have checked the voltages at the plenum heaters from each solenoid. I cannot remember that far back (15 years or so ago) and I will have to look, but I think I put a #0 wire from the starter bolt to the frame where the one battery - is attached to the frame! Thanks and if you have any more info to add, please do. BTW it was - 11* F this morning in Laramie and I did not need to go anywhere so I did not even try to start and my 2017 2500 was plugged in and still is!
gtwitch in wyoming

 

[Timd32]

Few links that could help.

Check your battery cables, could be getting high resistances in the cables and ends.

https://www.fluke.com/en-us/learn/blog/automotive/electrical-automotive-troubleshooting

I used this place a few years ago for my Denso Alternator parts. They have quite a few things that others did not have.

https://alternatorstarterrebuildkits.com/

Did you put 20k miles on the new contacts or 130k?

I think I have a spare set of starter contacts if you don't have a set and if they fit yours let me know. I'm never going to use them.

The Genos battery cables are the real deal, highly reccomend them if yours are older. Little bit of an investment for sure.

https://www.genosgarage.com/category/battery-cable-and-components

Good luck with your repairs.

 

[DavidC]

See what alt. you have as mine is a Bosch before ordering parts.

 

[gtwitch]

Mine is a denso and I still need a diode plate (need part #), I can find the light duty one for the gassers but not the one for the diesel and I think it is 136 amp but don't know for sure. The alternator starter rebuild site does not list it.
gtwitch in wyoming

 

[Timd32]

I can PM the email address I received my receipt from if you want to see if they are able to assist.

From what I recall I searched out their address and its an old school rebuild shop so they probably can get almost anything you need or maybe have a cheap core possibly.

Let me know.

 

[gtwitch]

thanks Timd32, My email is gtwitch@uwyo.edu

 

[Timd32]

Sent the info.

 

[JeepBuilder]

I have used this company for a lot of different repairs. From boats to bulldozers. They may have it. Not sure but still a good bookmark.
https://www.aspwholesale.com/alternator-parts.html

 

[Timd32]

I have used this company for a lot of different repairs. From boats to bulldozers. They may have it. Not sure but still a good bookmark.
https://www.aspwholesale.com/alternator-parts.html

That's a pretty cool site.

When I rebuilt mine (front bearing was shot) there was a small rubber insulator piece that just crumbled it was all dried out.

Looks like that carry that small part.

Nice breakout of parts and pieces.

Doubt I will tear it back down to replace could always just pick up the part just in case.

Thanks for the link.

 

[GAmes]

This thread is what I call good timing. My Denso died over the weekend. I've determined that all I need are brushes, $6.60. However, minimum order is $10.00 I watched a u-tube video where the replacement of the terminal block is recommended. What exactly does the terminal block do?

 

[JeepBuilder]

No sweat.. I was able to put a cheap GM alternator on a 450C bulldozer by using their hard to find conversion pulley. JD's have a super wide belt and they had what I needed. Great site.. Hope it helps the original poster too.

 

[HPSimpson]

I have used this company for a lot of different repairs. From boats to bulldozers. They may have it. Not sure but still a good bookmark.
https://www.aspwholesale.com/alternator-parts.html

Perfect timing thanks for information, I also use Larry B for my older '96 Ram.

 

[Timd32]

This thread is what I call good timing. My Denso died over the weekend. I've determined that all I need are brushes, $6.60. However, minimum order is $10.00 I watched a u-tube video where the replacement of the terminal block is recommended. What exactly does the terminal block do?

Been a while but I think it just transitions the winding and diodes over to the back case.

I broke mine only because my case was frozen and I went to use a impact driver on it and did not realize I was on the wrong nut and smashed it up.

Its a pretty simple plastic piece. I don't know of they really wear out per say. But easy to swap out to hit your $10

 

[GAmes]

Sounds like a plan.

 

[GCroyle]

GAmes,

Check the condition of the slip rings prior to doing the happy dance.

Early this year mine crapped out, ordered brush kit etc but slip ring no goody no more got a reman. They can be R&R I found out but it's a interesting task.

Gary

 

[GAmes]

OK, thanks for the heads up. I've ordered the parts already so I might end up with spares.

Edit. I didn't know what they were called but I did inspect the slip rings prior to posting. They hardly show any wear.

 

[gtwitch]

Thanks to TDR for this resource!!! I ordered from their site ASP Wholesale.com. Parts arrived in 4 days and alternator is on and tested out fine. Thanks to all who chimed in here.
gtwitch in wyoming

 

[JeepBuilder]

Great news!!