EVERYTHING in my car dims when I have to stop at a red light. Not only that but my radio cuts out. I've tried increasing my idle, but I'm only willing to take it so high, otherwise *CLUNK* into gear right? I know the lights dim a LITTLE, but this is just crazy... and it doesn't do this on my other cars. Where's the source of the problem?

Thanks for all your help guys!

MTV

I have never been too wise in electrical but i will take a shot in the dark and call it the alternator

I would second an alternator, possibly battery. If you have a voltmeter, measure battery voltage with engine off. Should be above 12, 12.6 on a healthy battery. With the car running, at idle, ~13. Rev it up and you should easily get above 13.

If your battery reads less then 12.6 with nothing running, I suggest you first try charging it before doing anything else. You can take your battery/alternator to your local kragen and have it tested for free.

Mine used to do that also I replaced the voltage regulator, that helped quite a bit. I think at idle It just isn't made to handle the lights, wipers, heater on high, the cd player and amplifier. with out the amp mine still dim a little but with it the voltage drops so much the cd player turns off, and mine is a cheepo that dosent remember where you were in the song and starts tha song at the begining AGAIN!

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Is this a new problem that just started?

My truck mysteriously went to heavy discharge at engine idle speed and even reving up the engine barely made it charge.
I took apart the alternator and found some of the diodes fell apart. I put in a new rectifier assembly and all worked well again.

You will simply have to do some trouble shooting to find out which problem(s) you have.

Well, I drove the car to work this morning (that's where I'm sending this reply from) and I packed an extra alternator just in case. It's not the Alternator, it still charges the battery just fine as I can see on my altimeter. I'm thinking it's either the voltage regulator, something to do with my starter (a bad field perhaps), or maybe even a bad battery cable. I'm hoping it's not the battery cable as they are hard to find up here. Remember that it's not an ordinary cable... it's got TWO wires coming off of it. Say, could the problem be with that little box mounted on my fender? That's where the one wire from the battery goes to. HMM

Encountered a similar condition with the original 45 amp alternator and mechanical regulator, learned the expensive way these stock regulators are not up the rigors of additional accessories and upgrading to a 100amp duel field alternator and mopar solid state regulator and 800CCA diehard cured all ills, now charges at a constant 13.5V, even will lights and all accessories running. BTW the paddock list duel battery cables..Dave

Where did you get this alt. and is it a direct bolt on?

Below is a list of what I would check in order...

1) Make sure the battery to chassis or block ground is good & clean your battery terminals.

2) Check alternator output at the positive terminal on the alt. Should be around 13-13.5 volts when running.

3) Clean bulkhead connector--can be years of corrosion in this electrical plug creating mass-resistance in the charging system, and for some reason dodge thought it would be a good idea to run all power from the alt/battery through the firewall to the switches, then back out the firewall to the accessories (lights, blower motor, etc)

4) Have your battery load-tested (usually free at most parts stores & shops) If it fails the load test, time for a new battery.

5) check/replace voltage regulator

6) Upgrade to higher output alternator (78 amp should bolt on)

I highly suspect a bad ground or weak battery. Good Luck.

-S/6

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The "Silver Bullet"
87 Ram D150

Custom built to my specs using a 77 Chrysler 360v8 alternator with new circuitry and a rewind job and did require some minor tweaking of the stock bracket. At the time I converted high output alternators were unheard on a slant application. If I were to do this again would use a GM alternator and manufacture/modify the brackets or just call Powermaster and order a 125 AMP unit (future efi/ac and elect. fan on the drawing board) Any time you upgrade, make sure your wiring is able to withstand the additional current, which is the reason I performed a complete engine bay/charging circuit-dash rewiring job using a custom harness built so circuits can be added/deleted without cutting or splicing using severe duty 10GA wire with all connections silver soldered and no bulkhead connectors....Dave

Gosh, I'd be afraid of putting such a high-output alternator on anything that did not require it. My concern is if something were to go wrong that would cause this thing to go into full output it would fry everything in the car. Lights, radio, battery, and wiring.

FYI - studying the RPM versus Current Output of Delco Remy 10SI alternators I see that the mid-output alternators (55 or 63 amp) put out more current at a low RPM than the "high output" models. The high output models don't catch up until a higher RPM.

Now that 100 amp Chrysler model may be different in that it is designed to also put out at lower RPM? I don't know.
Anyway, I've been happy with the stock alternator on my Valiants and Trucks. Only with heavy electrical load at slow idle in gear will cause discharge on the ammeter. Stepping on the gas pedal slightly brings the charge rate upto break even or more.

Correct craig it was designed with low rpm in mind. Thought about the full output diaster potential and installed circuit breakers where necessary to avoid that (industrial circuit breakers, mind you, not automotive grade).

My fear has always been of melting the regulator, but its been over 7 years and this has never occurred. The best thing about it is I have a expandable system after having spent months designing and parts matching. The actual install took only 3 days and I have spare harnesses should they ever be needed.

Of course I still have all the original parts in working order, so I could always go back.

Craig, it is a general rule of thumb that an alternator in the same case, with a higher output rating, sacrifices current output at lower rpms.

But that is not true of all high output alternators compared collectively. My powermaster alternator is rated at 120a @ idle, while at speed it tested out to be well over 200.

Well, I just got the problem solved about an hour ago. -S/6 was right in his first solution: The damn block ground was loose... just ENOUGH to cause a loss of power. I noticed immediately that the starter was getting more juice and then I put it to the test. I took it down the road and turned EVERYTHING on... even cranked the stereo, it's ALL FINE NOW!!! Thanks everyone for your help!

What would we do without sites like this?!?!?


MTV

Sounds nice. Where/how did you get it?