Overcharging then no spark or fuel


Old 06-17-03, 07:31 PM
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Overcharging then no spark or fuel

Hi, I have an 89 Dodge B150 (going by date on door jamb) passenger van. 3.9L V6 engine.

I recently noticed a foul egg smell and discovered my battery was bone dry. I also inspected the date and it was seven years old (was in it when I got the vehicle). Well, I figured the battery was too old and bought a new one. Then two days after that I checked under the hood and noticed that this battery was spewing acid from loose caps. I checked the charge at the battery while it was running with a digital multimeter and it was at 18volts.
That was just the beginning of my problems.
I went to the local parts store and asked for a voltage regulator, $12 bucks. Hmm, I thought, this is gonna be cheap. But then I discovered that there is no voltage regulator like the one they supplied me with on the firewall anywhere. I brought it back and they said to have a mechanic look at it because it had a newer style alternator. Called a mechanic, told me to bring it over for an inspection by starting the vehicle and then removing the battery cables so I don't blow up the battery on the way over. Well, I removed the ground only and made it about a block and it went dead. Towed it back to my place and checked it over for what I could. I have no spark at the plugs or the coil (but the engine turns over) and cannot hear the fuel pump run when I turn the key.

What did I likely blow when I foolishly ran it with only the ground off and the charging system sending too much juice?
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Old 06-17-03, 07:50 PM
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well there is a good chance you may have damaged the pcm which also controls the voltage output of the alternater, but i would suggest towing it to shop to make sure that is the problem and not something else, it will also need the wiring checked for shorts to ground to determine if the pcm was causing it to overcharge or if your field wire is shorted to ground, or if alternater is shorted to ground internally.
Old 06-17-03, 09:06 PM
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BeJay is correct.

Never, ever, ever, ever run a vehicle with the battery cables disconnected like that. Good chance you've also wasted the alternator too .

On a Chrysler like this, the PCM controls the voltage regulation. The 12 dollar regulator you were sold is likely the on internal to the alternator. Not DIY replaceable for most folks (you have to be adept at rebuilding these alternators---Chrysler doesn't offer breakdowns/parts on most starting with about 1989).
Old 06-19-03, 03:29 PM
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It won't take long but any time you think it's electricial check the fuse box. Good luck
Old 06-21-03, 03:55 PM
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well it's been four days, have you found anything yet, if not, here are some comments

the next time ANYBODY has this problem, unplug the field wire from the back of the alternator(usually green) when you have to drive it, you will only be able to drive it as far as you can get on the battery alone, i don't have to tell you what can happen by driving with the battery unhooked, who knows where all that extra voltage went that the battery was absorbing,
unless this 'mechanic' is a personal friend, it might be time to look to someone else,
some things to check...if the check engine light comes on with the key on and engine off, the computer might have survived, but it might also be bad as it controls the charging system, but it usually fails the other way(no charging) most times an overcharge is caused by that same green wire being shorted to ground somewhere between the alt and the computer. if the computer is good on both conditions, you might have burn't up one or more fusible links from the original overcharging problem(you have two problems now), they should be so conveniently located in/on the harness to the left of the brake booster looking under the hood, fixing them isn't so easy, they look like a 4-6 inch piece of wire taped or zip-tied outside the main harness, give them a small tug, if the insulation isn't completely melted off, pulling on them will reveal the bad one, as the wire inside melted away, tugging gently will break the insulation, a good one will feel tight(like pulling on any wire) if it is bad(melted/broken) you MUST replace it with the same EXACT color wire as the link was, not the wire color it's protecting, not replace it with straight copper wire, with fusible link wire(this is important to preventing future FIRES). reread that last sentance! you must also solder the fusible link wire to good clean wire, which is where the hard part starts, first the wire runs right behind the brake booster, second, it's usually a thicker wire than some soldering irons can completely melt to(i usually loosen the brake booster enough to get the harness out enough to repair) there should also be "i think" two links coming right off the positive battery terminal.

if all the links are good, you will need a wiring diagram to see why your 'asd' and fuel pump relays are dead. i can't see it not being a fuse link and/or computer though(along with your original overcharging problem), they are the first things i'd look at

hope that helps

if you have any more questions write back here, or are unsure about this, get someone who isn't(the dealer might not be too much more expensive on this one, they would be very familiar with this van, know right where to go and shouldn't charge too much 'diagnostic time')

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