Archived PCM problem?

[San Felipe Bob]

The GEN light is on and the Altinator is not charging.

The Alt. checks out fine at the shop on the test machine.

I've read in the Hayes Manual that he Voltage reg. is in the PCM.

Can this thing be "fixed".

I'm out working on checking all the ground wires.

SFB

 

[2-ND TIME]

Alt not charging ???

Sorry don't know the exact particulars of your truck.

Do you have (probably) a gauge if so gauge should move up scale after starting and or manifold heaters come on.

Do you have a multi meter /volt meter. if so put it on DC (is it digital or analog) scale for 20 volts if analog. Should go up scale when you start.

This of coarse shows charging then if not or when not you will know that.

As for if the PCM has the regulating cct in it I don't know sorry.

Hope this helps if not I will help more.

 

[tp0d]

Does the tach work when the engine is running? If not, your problem could be the crankshaft positioning sensor, not the pcm. No real good way to diag it without a scope, but you can check the gap on it with a . 050 feeler gauge (brass or plastic)



If the tach works, the voltage reg could be bad in the pcm. There is a way around this, adding an external voltage regulator to the circuit. Not sure of any part numbers or wiring diagrams, but I know its been done. try a search on some of the forums. .



good luck



-j

 

[bavrit]

I have a pcm

I have a good PCM out of a 97, it came out of a truck with a manual. I do not know if this makes a difference. Numbers are 500AC, EDEOP74E, P56040, T2896, RNZAA. Call me 503-803-2929 if it might work.

 

[San Felipe Bob]

It's fixed!

The brushes were worn out.

I went for the Auto Zone life time unit. 144. 95

No more problems and the transmission shifts sooo much better.

Thanks for all your input!

SFB