1994 blazer not charging correctly
 

i have a 1994 fullsize blazer. Installed new 200 amp alternator new battery still only shows 10 volts on gauge. Checked with multimeter actually putting out 13.6 which still isnt enough. Did the jumper cable thing with no change in readings so that kinda rulls out the wires. This all started when i installed a rebuilt starter from autozone. When i hooked the battery back up i heard a pop inside the truck and the check engine light immedianyly came on. Checked codes showing iac valve low voltage at pin 1 which would be a knock sensor and a code for fuel mixture. Thats also when the charging thing came into play. Checked all fuses and relays they are all good. Any thoughts guys? Could it have blown something in the onboard computer(ecu)?
also installed new iac valve cleared computer and its still showing iac code.
please any suggestions or thoughts would be appreciated.

what have you done with the starter since?

When you measure the battery voltage with the negative or positive pole removed what is the voltage?

Charging at 13.6 volts may be normal in one of several conditions. An empty battery which draws lot's of amps can also pull the voltage down.
RPM being too low for this alternator to go to full voltage at idle. The battery is fully charged and no load on the alternator.

Something popped inside...

The IAC (i guess - idle air control) low voltage at pin 1 may be indicative of something happened to the ECU or to the wiring leading to the ECU.

As it happened with the new starter in, I think I would start with the starter to make sure there is no wrong polarity or a short in the starters shunt which throws current where it should not be. To be on the safe side I would not attempt it with the starter in the vehicle but remove it for bench testing.

Starter ecu
 

I have rechecked all starter wiring i have recently installed new ecu. All same conditions still exsist. Of course i had to use my old prom in the new ecu. Hooked up or not alternator only puts out 13.6 volts but my guage shows 12. Could there be a fusinle Cb link burnt somewheres?

If it all started with the reman starter install i would be starting with warranty on the starter and see where it leads you. That is when it happened so that would be the place to start. An internal problem with the starter pulling to much voltage could be it.