[Rich Camozi]

I need help. :help: My pick up is over charging to 16 volts. I put a new altinator in, I put countless regulators in. I cleaned all the terminals and everything I could think of doing, and it still charges to 16. The book says there is an Engine Control Module (emc). I don't know where it is. If there is one, does it control only the voltage and where would it be and how do I fix it?
Thank you.
Rich

 

[tdimark]

91 has both types. 1st 91 non intercolled engines have a voltage regulator on the firewall. 91.5 intercooled motors have the ECM under the drivers side fender aside of the battery. the bad if you have the intercooled motor the ECM might be bad and is not repairable by us. there is a way to put the voltage regulator back on the firewall when this happens,sorry to say i cant remember off hand.

 

[Chump]

Have you pulled any error codes off the computer or do you have a Check Engine Light on? Are the battery/s in good shape?
I believe on the VR that is mounted on the firewall it should have 2 wires...1 Blue and 1 Green. Follow the green wire from the regulator clear back to the alternator and check to see if it it shorted to ground. If it is, it will keep the alternator full fielded at at high output.

Non-Computerized

Control Module Location
The control module is located on the drivers side of the firewall in the engine compartment.

Computerized

Single Board Engine Controller (SBEC II)
The engine controller is located in the engine compartment, on the left inner fender behind the left headlight assembly.

 

[Rammer64]

First off. What guage are you using to say that it's charging at 16volts?
The dash gauges aren't that accurate. I would use a DVOM (digital,volt,ohm meter) and check the actual voltage. You said you already replaced the alternator and voltage regulator, so you must have an early 1st gen prior to ECM controlled voltage. There is no external V/R on the later gens with the SMEC. Voltage is controlled through the ECM. Are the batteries overcharging? Do you get the sulpher smell or are you adding water/electrolyte to the cells?
Normal charging should be btween 13.2 and 14.7 volts. If it IS charging above 15volts as you describe, then I would suggest cleaning all engine and body grounds. Make sure the "green" wire from the alternator to the V/R isn't grounded or chaffed against anthing. I have also seen "NEW" voltage regulators be faulty.