Why wont my 1st Gen charge? Please help guys!

WILD_PHIL

WILD_PHIL

New member
I have a intercooled 91 D250. Put a yellow top optima on it and started driving it. It killed the battery. The lights were going dim also. Put another battery on it, cleaned the gounds, thought it was good. Drove it a few days, dead battery. Cranked it up with the battery charged again, disconnected pos cable, truck died. Replaced the alternator, disconnected pos, truck died again. It keeps killing batterys.

This is my first 1st Gen, first Cummins, so im flying blind. On a positive note I took it to the track and ran 17.5s after a few runs(getting use to racing the truck). Not very good but for a 300k mile truck, with a getrag WITH a PTO built in, and just the pump turned up, with bald tires, I would say thats not bad. Right?

Please guys any help is greatly appreciated.
 
I wish I could help you out better. but i can say i read a thread on cumminsforum with the exact same problem. And it ended up being very loooong. Might switch over there a bit and do some searching....
 
make sure you don't have any broken wires by the alternator, the last charging problem I worked on this year had a broken connector on the alternator.
 
Well I have been checking wires and havent seen any thing wrong yet. I believe this is going to have to be diagnosed by the Cummins Mechs. The truck spent its life as a tire truck and for some reason it have a pto that looks like your average 80s model chevy. 1000.00 worth of wire running through it. To me it sounds like the Alt, but I dont know. Its putting off like 12.5 at the alt, and at the batterys. Before I cleaned the grounds it was putting off like 6.8 volts at the battery.
 
The computer that turns the alternator on and off on my 95 12v went out. You could start the truck and shut if off and it wouldn't start back.
 
Dude, is it a 91 like you say or a 92 thats in your sig?

2 different charging systems.

If a 91, check the volt regulator.

If a 92, ECM or CPS is your problem.
 
I need to change my sig. I bought this truck last year of craigslist while I was deployed for 1000.00. Im the second owner. But it is a 91. The speedo was disconnected when I bought it but does work now, and its a base model truck. Doesnt have cruise control from what I have seen. So how do I check the voltage reg, and where is it? Guys I appreciate the help.
 
Charging problems

I had the exact same problem with my 1991 D250 non-intercooled truck, I replaced the battery and still the problems occured.. After running a few electrical tests which said the alternator was bad, but actually turned out that the VOLTAGE REGULATOR was shot(located above the turbo on the firewall..

Hope it helps... Good luck
 
Well just ordered one from Auto Zone. We will see. I pray that fixes the problem. Any idea why the intercooler would have anything to do with ordering a no a/c belt? Trying to get rid of the condenser and they guy said the belt for a i.c. truck was more. Doesnt make any sense to me.
 
IC belts are 7-rib, non-IC belts are 8-rib.

The voltage regulator is on the firewall of non-IC trucks, above the engine; it needs to have a good ground between it's case and the body, an ignition-on +12 volts on the blue wire and it should output a ~5-7 volt signal through the green wire to the back of the alternator.

Yes, on intercoolered trucks the alternator won't charge without a CPS signal.
 
Regulator. They are cheap and alot of places carry them in stock. Mine was over charging fixed alternator and then lost all voltage. Turned out regulator. GL
 
Dang thanks alot guys. Idk why I didnt go cheapest first. These motors are so mechanical I didnt even think about the regulator. Anyhow picked one up today before work and put it on during my lunch break. Problem solved. Once again thanks to every one of yall. Now I can start my build.

Since I have yalls attention, what do yall think about doing twins with a hx55? And how does 470.00 shipped sound? Another guy on here has one that he claims a friend tried to use as a single and it didnt work. They tried to spool it a few times in a drive way and thats all it has on it.Had a buddy say the hx55 has a thin shaft in it and isnt that great. Im aiming to build a streetable drag track.
 
Oh and if yall dont want to ruin the guys sale I understand, just looking for good info. Also I am trying to twin this with a hx35 stock turbo.
 
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