1-wire Alternator troubleshooting

[splitsvillage]

I've been putting a bit of time into this long retired '97 BB Cat 3128 prospect. After I found a link one of you shared for manuals, I managed to find and free up the body power supply solenoid by taking it apart and giving it some attention. Now power is supplied to all that important stuff including wipers and running lights!

But it did not solve the charging issue. I'm looking at a couple things now, having read up on the forum and webs. It wasn't solved by cleaning connections and tapping at it yesterday eve when I was last at the bus. It has battery voltage. It has one, brown, wire on what I believe is the "i" terminal.

First, I guess I'll try checking the alternator bulb if its actually a two-wire set-up and possibly flashing the "R" wire on the alternator if it's indeed a one wire set-up.

The tach is intermittent and I suspect that it is the one other wire attached, not a lamp wire (although it is attached to the I, not R? terminal), and the alternator is simply yet to begin charging under it's own residual magnetism.

if I understand correctly, there is a bar that is severed if it is used as a 2 or three wire system, but I don't know where that is in order to check it. It has the plug overing 1 and 2. Here is a picture

Am I on the right track? Vern

P.S. I was reading about the alternators here

[splitsvillage]

Acquired the bus. Think I fried something since I had some tach but now have none after trying to re-energize the field circuit and probably mistakenly jumpering to the 'I" terminal the first time.

[BlackJohn]

I really have no advice but to take the alt off and either get it rebuilt entirely or replace with new.
Gremlins are one thing but if you made a mistake trying to flash it that gets costly. Take it to a pro and save a lot of aggravation. Or take it apart yourself and buy the parts necessary for the rebuild. At least you can learn something which you can then share down the road.
Parts don't last forever so...
Not knowing really what you did,I doubt any of us can correct it for you.
Good luck.

John

[splitsvillage]

Thanks for the reply, John.

As luck would have it, I lost all power in run and start positions today after having cleaned instrument cluster connections. Initially things were much imporoved and reading voltage and fuel level more accurately. Seemed buzzers chimed up also. Until I went to start it and everything was gone. at first it came back to having power in the run position but then did nothing. In the accessory position I have maintained the solenoid 'clunk' and have limited use of the panel beyond which the solenoid starts 'hammering'.

I investigated battery grounds but will do so more thoroughly tomorrow. Both batteries were at 13+v. I wonder if there is a fuseable link at issue, perhaps. Any thoughts?

Also, one is supposed to jumper to the 'I' terminal on the Delco Remy 19si for that purpose. Pardon my mistake in the previous post.

[Rusty]

Just a thought, but how are your batteries setup? A pair of charged batts in parallel?

You didn't leave-out any pigtail battery connections?

If I suspect a bad ground, I'll throw a jumper cable from neg post on battery to alt bracket, etc to test.

[splitsvillage]

Originally Posted by Rusty

Just a thought, but how are your batteries setup? A pair of charged batts in parallel?

You didn't leave-out any pigtail battery connections?

If I suspect a bad ground, I'll throw a jumper cable from neg post on battery to alt bracket, etc to test.

I have two well-charged batteries in parallel with each other. They have leads for a 24v fuel cut-off solenoid circuit. The configuration was working until I was cleaning up. Another thing I did was to disconnect the intake heater solenoid pigtail to cut down on battery drain while I was working with things 'hot'.

I tried using booster cables from the battery to the frame at the shock mounts after cleaning them up down to bare metal to no avail.

[BlackJohn]

Originally Posted by splitsvillage

I have two well-charged batteries in parallel with each other. They have leads for a 24v fuel cut-off solenoid circuit. The configuration was working until I was cleaning up. Another thing I did was to disconnect the intake heater solenoid pigtail to cut down on battery drain while I was working with things 'hot'.

I tried using booster cables from the battery to the frame at the shock mounts after cleaning them up down to bare metal to no avail.

You lost me somewhere. Is this on the 3116 or the 3208?

[splitsvillage]

Originally Posted by BlackJohn

You lost me somewhere. Is this on the 3116 or the 3208?

3116. at first I thought it was the 26. Is this the same as yours? Do they not all have 24v fuel solenoids?

[BlackJohn]

Originally Posted by splitsvillage

3116. at first I thought it was the 26. Is this the same as yours? Do they not all have 24v fuel solenoids?

Ok thks, now you are making more sense to me.

Yes, mine is a 3116 also.GMC chassis

So my fuel solenoid is 12V and has two wires, one for each coil in it. One opens the fuel gate and the other holds it open after warming up I think.

My alt is a 2 wire though with only one cable back to the battery connection.

You might have a defective ign switch and or cleaning of the cables at the starter solenoid and the starter cable itself. They like shiney, clean metals or they act intermittently.Good connection will start mostly, bad connection, everything seems dead.

Did you drive that from Cape Breton up home? How far and how did that motor work? They are made for that country for sure.

John

[splitsvillage]

I've tried to reply twice now, John, and every time I hit post quick reply it has to log me in again and the whole message is lost. Damn if I'm not P.O.ed with this. I'm lucky not to have damaged my screen. Will try again later.

[Rusty]

clear your cookies on your browser.

Whenever I type a longish reply, I select all the text and copy to clipboard prior to submit. I hate to do stuff 2x.

[splitsvillage]

.It's looking like a huge project right now and although I havn't gone back at it to ensure good grounding, batteries not ghosting, etc., it may just come back on-line when I do. I am having a hard time with considering this bus a parked bus based on that short ride. Is that what you are referring to, John, when you say it's good for cape breton? (I found a label that said 215hp on mine, that also the case with yours?)

Drives really well. May be sway-bars? I drive school bus and enjoyed the short rip to get it home, but it is summer break and I forget what it's like.

Tach wire was on the I not R terminal. Haven't got back at it yet

there are two wires with what looks like a fuseable link on one lug to the bat terminal of the alternator. The 1 and 2 terminals were not cut so that makes it a one-wire.

I guess we have the same rig, John.

[BlackJohn]

Hey splits, thought the crows got ya! But it has been a long weekend here, can't remember if that's the case in NB.
Great pic thx, good lookinn rig.
I was thinking with that engine and tranny that is the cat's ass down in the Cape. All those hills and twisty roads which climb up and down. That's where I hope to take this bus when I get done, if ever.
Home base was on the NS-NB border at Tidnish Bridge so hope to get back soon.
Not sure on the hp rating of mine, but from what I have read I think it's lower than yours. But it likes to romp on the hwys, power to spare.

Keep at it, you'll get it figured out and working good.

My bus also has that code you mentioned in the other thread but dammed if I know what it means. Emission exempt I think.

Good to hear from you,

John

[splitsvillage]

Thanks John. I had presumed you had meant the handling on curves with this set-up (sway bars and such). Others have noted the good handling characteristics of the so equipped GMCs.

I believe I have my electrical woes licked. My body ground braided cable was rusty. The alternator brush wire was severed. I hope that is all behind me now that I am replacing the brush and regulator (as a precaution) and repaired the body cable.

Perhaps if you are coming through NB on your trek to CB you will stop in to Apohaqui. Cheers, Vernon