I suspect you have multiple problems. If they all started at the same time, look for things they have in common, such as a wiring harness that fell down onto hot exhaust parts, corrosion between adjacent terminals in a connector, and things like that.
To start with, the Hall Effect pickup assembly has to be working if you have spark and injector pulses. When signal pulses show up at the Engine Computer from that sensor, that tells it the engine is rotating, and that means it is time to turn on the automatic shutdown, (ASD) relay. That relay sends current to the ignition coil, injector(s), fuel pump or pump relay, and the alternator field circuit. It's that circuit you're applying the 12 volts to with your jumper wire. This suggests the 12 volts isn't coming from the ASD relay, so we have to determine if that relay is defective or if the computer is failing to turn it on.
The place to start is by monitoring the voltage in the circuit you're applying 12 volts to. Leave that jumper wire off, then connect a test light there. You might be able to use a digital voltmeter too, but they usually don't respond fast enough. You should see the test light turn on for one second when you turn on the ignition switch, then it will turn off again. You might hear the hum of the fuel pump for that one second too. If you see that, the ASD relay is okay and the computer has control over it. If you do not see that, check for 12 volts on the red wire in that relay's socket. It's not common for that to be missing so we'll address that later if necessary.
Due to the location of the ASD relay, it is susceptible to moisture and corrosion. Check the terminals in the connector for corrosion. If you see any sign of that, a good suspect is a buildup of corrosion between the contacts inside the relay. You might want to pop the cover off the relay and look inside for that damage.
The running problem you described sounds like a failing MAP sensor, but also check for a cracked vacuum hose going to it. Check to see if the recall has been performed that added the bleed valve shown in the fourth drawing.
Check this page for instructions on reading the diagnostic fault codes yourself:
https://www.2carpros.com/articles/retrieve-trouble-codes-for-chrysler-dodge-plymouth-odb1-1995-and-earlier-car-mini-van-and-light-trucks
I can interpret the definitions for you if necessary. Be aware there is likely to not be any codes at this time. If the battery was disconnected or run dead, any fault codes were erased.
The charging system is pretty easy to diagnose. We'll cover that later once the other problems are solved. In the meantime, look for a really fat ground wire or a braided ground strap connected between the engine block and the frame of the alternator. The wire often gets overlooked after it was disconnected. The braided strap commonly corrodes off. The alternator is mounted on rubber mounts to reduce vibration, so that wire or strap is needed for the system to work. To double-check for a good ground, just ground the negative lead of your voltmeter to the battery negative post or the engine block, then check for voltage on the frame of the alternator. If you find voltage there, you'll need to add a ground wire.
Images (Click to make bigger)
SPONSORED LINKS
Tuesday, February 5th, 2019 AT 7:16 PM
