Electrical problem

PRO DEMO

MEMBER
1999 DODGE DAKOTA
6 CYL
4WD
325,000 MILES

99 dakota 3.9; 4x4, heater core blew and "steamed " inside cab. Did emergency bypass in engine (before firewall). Started fine. Immediately and while driving since (got heater core replaced professionally), car starts fine, but stalls 1 min later. Will not hold idle. Chrysler replaced all distributor, cap, rotor, all new wires, sp plugs, AIS sensor. Still stalls. While driving must run minimum 1500 rpm as it wants to drop by 500. Also now every 3 days (1 month old Eliminator) battery dead and needs boost. Sounds like a short but cannot find. Also computer gets no reading on some codes ( told by mechanic ). Any thoughts on this.? Where to look? Cant afford another vehicle.
Tnx much.
Raymond

1 Reply

CARADIODOC

MECHANIC
33,879 POSTS

Hi Raymond. First of all, all the parts you listed will not cause a stalling problem. They would cause a misfire. If the engine will always stay running if you hold the gas pedal down a quarter inch, the Engine Computer just needs to relearn "minimum throttle" after the battery was disconnected or run dead. To meet the conditions for that to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.

If the engine stalls and won't restart until it cools down, suspect the crankshaft position sensor. It is mounted in the transmission bell housing right in front of the heater core hose connections. It's air gap is critical too. One common problem is people removing it and reinstalling it without using the special thick paper spacer to set the gap.

As for the dead battery, measure battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. If it is, suspect a drain, but if it takes three days to run down, and you drive it every day, it should be recharging as you drive. If the battery goes dead in spite of driving it every day, it is more likely the alternator isn't working. If that is the case, you will find closer to 12.6 volts or less at the battery while the engine is running. If that's what you find, measure the two voltages on the two small wires on the back of the alternator. They could be plugged in or there could be two small nuts holding the two tabs coming out of a small black plastic block. One of those wires must have full battery voltage but it will only be there while the engine is running. The secret is the voltage on the other wire. It must be less than the first one but not 0 volts.

Caradiodoc