discharge from pcm fix..

[goodrotty505]

i have a 91 250 ram van and for the last 2 mos has been discharging the battery. so i get a new alternator and this doesnt fix the problem....i scratched my head for 2 mos chasing wires and shorts..no avail...i could not afford a pcm and wont buy a used one.....the fix was to buy an older mopar regulator to bypass the pcm..the regulator has to be grounded tight.the harness at the alternator, the blue and green wires need to be cut so you can make new leads (same color) . the remaining 2 leads are wired to the regulator w a split going to the dark blue ign wire at the steering column....the blue wire gets the split to the ign.....ive got around 14.5 volts charging at idle and all the gauges work..

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[goodrotty505]

Oops i meant ecm...sorry

[landyacht318]

Does doing this light up the check engine light? Is there always a code stored?

Nice improvisation though. I bet the older regulators allow more amps more quickly back into the battery. The ECM controlled regulators drop the voltage down too early in my opinion because they are worried about overcharging.

Might want to check it voltages after a long drive(full battery), and see if it had fallen to the 13.6 range. Or just use a wall charger overnight and test after 10 minutes.

[goodrotty505]

unfortutunately the light stays on..and the code is still there but the volts are 14.5 at idle.....i didnt even get that w the ecm

[landyacht318]

Here in California, a vehicle that has the check engine light lit will not pass a smog test. If the light does not come on at all when starting, it will also not pass, so removing the bulb does no good.

I regularly see 14.7 volts. I have a Solar panel on top, and a battery monitor inside. When The batteries are above 90% the voltage drops to 13.6 or 13.7, and much to my annoyance the amps drop down to real low numbers, so that last 10% takes forever if relying on the alternator. The solar system also goes open circuit when the alternator is charging with the batteries above say 75%, so It does not add to the mix, much to my annoyance.