My dually is my only vehicle and it would charge on and off and now its not charging at all any one have advice on Wat to do because the alternator is still good. Thanks, Dominic

 

Is anything else coming and going, like OD, cruise control, tachometer?

Quick alternator test. Go at it with a test light, engine idling. Bright on the heavy battery terminal. Bright on one of the field terminals, dimmer/blinking on the other field terminal.

If one of the brights is missing, it's wiring. If all are there except the blinking field terminal is dark, the alternator is bad. If the blinking terminal is bright, control (PCM or it's input) is bad.

 

Yes my tachometer,its a 5 speed. Dominic

 

Sounds like a bad crank position sensor.

 

Faith has a procedure in the sticky which tells you how to diagnose and fix the issue.

 

The CPS (Crankshaft position sensor) provides engine rotation pulses to the PCM. The PCM fields the alternator. It will not field the alternator if it doesn't get CPS signal.

Some possible faults:

CPS connetor at top front of engine (3 pins)

Engine harness connector under the intake manifold near rear of engine. (10 pins)

PCM grounding

PCM connector

CPS gap to flywheel (.050")

And once in a blue moon eclipse the CPS actually fails.

< edit....CRS attack. Changed tps to cps>

 

Ok heres what I got the power off the alternator has power and the 2 little pins have nothing. And i didnt know you had to gap the cps but its never been replaced I wasjust saying haha

 

That tells me the alternator isn't getting field power from the ASD relay. That's the front relay (of 3) on the drivers side fender. Try swapping it with the rear one (the AC relay) and see what happens.

It would be good if you got the diagrams and traced it out for yourself.

ASD relay and PCM get power from the same fusable link the other engine control stuff does. If it were bad, it'd shut down.

ASD relay coil gets power from the DB ignition wire
ASD relay coil gets ground from PCM pin 51
ASD relay switched power goes to PCM pin 57 and the alternator field top screw.

Alternator field bottom screw is grounded by PCM pin 20

 

Its still working on and off I switched them and it looks to be the pin by tests, the external conversion is what im gonna do , is the better directions or pics of what to do on it the sticky doesn't show if factory wires stay on the alternator or if they come off, Dominic

 

They would come off and be isolated (taped) of course.

What you're missing is that the fault affects more than just the alternator. Probably if you trouble shot the ASD relay failure, you'd solve all of them at once.

In retrospect, if you have to ask that question, you're in over your head. In other words you might do more damage than good trying to fix it yourself.

 

What do you mean im good at wiring i just wasnt sure if they came off or if they stayed on and they would work together but i tired of this charging system and i hate messing with the wiring on first gens cause there known for flaws. Dominic

 

If there is no signal from the cps the asd won't think the engine is running. Then the truck won't charge so if the tach is also not working when the truck stops charging I would still check the cps signal. Cps could just be dirty also.

 

How do you check the signal for the cps

 

What year animal are we discussing?

It makes a difference.

 

93 5 speed