alternator/starter issues with D5

[KMB83]

the other day i bought a new alternator for my D5 96J series. took off the old 19amp, and replaced it with what the manual said was used for the upgraded light package... 25SI delco 50amp 24v.

well i put that in. it was positive pole, with a negative frame ground. i tied the frame ground into the same bolt as the starter frame grounds (it was clean/free of paint)

after i fired it up and was seeing if it was working two not so good of things happened.

1st. the volt gauge only read 12v on the machine rather than if it was getting a charge 14v. the alternator generates plenty of power when i had the volt meter on its poles by itself....

2nd. turned it off and then tried to restart it and nothing out of the starter.

did i fry something? i never smelled anything cooking. by theory hooking the two on the same frame bolt shouldnt make any difference.

the volt gauge on the machine still reads 12v when i try to start and get nothing or when i try the glow plugs (it should dip under 12v).

i'm not much of a wrench bender but this should have been something pretty cut and dried and now is getting out of hand....

thoughts?

 

[Iron Horse]

I'm a little confused , you took off a 12 volt alt and fitted a 24 volt one ? If you did you have fried the battery and that will be why it wont crank .

 

[KMB83]

sorry for the confusion. the whole system is a 24v old and new. the gauge was a replacement and reads 12v stopped. 14v running. and 10v when you heat the glow plugs.

 

[willie59]

I'm way beyond confused! Let me see if I got this; we have a 24V system. We have a gauge that reads 12V stopped, 14V running, and 10V when you heat the glow plugs.
What's wrong with this picture?
Let's try; removing the gauge, throw it away, and install a new voltmeter for a 24V system.

 

[sandy]

Ok so you have spent $$ on a new upgraded alternator.
Then try to see if it works with a suspect 12v guage
Spend a little bit more and get the right guage !
Then check your wiring and conections , and hope you havn't blown the diodes in your new alternator. Then check your wires and cables to your starter.
If your having a real bad day it might be dead as well for no good reason.

 

[KMB83]

don't get hung up on the machine gauge. used to be the county's machine and that is what they replaced it with.... go figure. the starter is getting power to both poles. i checked this with my 24v HAND HELD meter, not the dash gauge. the alternator still works the last time i had the machine running, i'm just befuddled as to why the starter isnt functional

 

[willie59]

We're not getting hung up on the gauge, you have to look at it from our perspective on the outside looking in; the 24v, 12v, 14v, 10v you describe is, for us, what the heck???
As for your starter; again, we're not there to share in this little mechanical adventure with you, we're not seeing with our eyes what's there. So, we have to start from the beginning with the very basics. 1) Is the positive battery cable connected to the post on the starter solenoid? If so, connect the positive lead of a handheld votmeter there. 2) Is the negative cable of the battery connected to the ground post of the stater motor? If so, connect the negative lead of handheld voltmeter there. If it now reads 24V, good. Engage start switch. Does meter hold 24v, or does voltage drop? If it drops, bad batteries or connections. If it holds, move your meter positive lead to the "switch wire" post of the starter solenoid. Engage start switch, your meter should read 24v when start switch engaged. If it doesn't, you've got wiring or switch issues. This would be the time to make a jumper wire connection from the battery cable post on the solenoid to the switch wire post of the solenoid and see if starter reacts. You should have your voltmeter connected to the pos & neg battery posts of the starter when doing this so you can monitor any voltage drop. Try all this and let us know what happens.

 

[bobcatmechanic]

try bench testing the starter also pull it off and put twenty four volts to the positive side and touch the negative cable to the signal post on the starter it should engage and spin that will tell you if the starter is good

 

[KMB83]

to all, I appreciate the help. here is the ending of the story.

took off the dash cover. lo and behold somebody wired in a fuse. the fuse was a 20amp. the new alternator zapped the fuse. alternator/starter both very functional. someone at the county musta thought that was a good idea. who knows. also stated earlier i aint much of a wrench bender.....

there are times i feel guilty not paying something for this place. and the free wisdom floating around in here.

thanks again