Lt1son

Well after relocation of my battery my scanmaster and stock gauge on cluster reads around 12.7/8 as low as 12.3/4. battery is new as well as alternator. if I put a meter on back of alternator I get 14.2.. hotwire kit to fuel pump also reads over 14volts... I have a junction block where stock battery use to be and that reads 13.6/8 as well as battery reads the same 13.6/8. Im not over concerned about the battery voltage and dist block. My concern is that the PCM is reading that low. Will that have an impact on say injectors or oxygen sensors? any input would be great thanks. Also 4gauge wire from alt to disc sw and 2gauge from starter to dis sw.

Injuneer

Not unusual for the PCM system voltage reading to be up to 1 V lower than the voltage measured at the battery. Did you notice a difference before you relocated the battery? A ~1.5 V difference seems like it may be excessive.

I would use the factory PCM wiring diagrams to work your way through the connections for the PCM BAT, PCM IGN and PCM grounds, making sure contacts are not corroded, wires are not damaged, etc. This is Shoebox's 95 PCM wiring diagrams... 94 is not a whole lot different, although the PCM BAT fuse was in the end of dash panel in 94.

4th Gen LT1 F-body Tech Articles

I can give you a linke to a 94 factory manual download if you want.

The PCM regulates the 5V reference voltage it supplies for many of the sensors. The tolerance on PCM voltage appears to be fairly wide. For DTC 50 - System Voltage Low to set, the voltage has to drop below 8.0, for DTC 53 - System Voltage High, has to exceed 17.1 V. The code writeups indicate "Normal battery output is between 9.6 - 16.0 Volts." It would appear they have accounted for that range of operation in the design of the PCM circuitry.

Won't affect the injectors in any case.... 12V power comes directly from the under hood fuse block. The PCM supplies the ground to fire the injector. The PCM supplies the O2 sensing elements with a reference signal of 450 milliVolts, so that would be regulated internally. The O2 sensor heaters are powered by 12V directly off the underhood fuse block, and do not interface with the PCM.

Are you sure the wire gages are adequate? This writeup recommends single-ought

Trunk mounted battery

What did you use for a ground?

Lt1son

I could have sworn before the relocate I never noticed the factory gauge below half which in turn made me look at the scan master. I used 4 gauge off alt to kill sw and 2awg from starter to sw. My ground wire is 2/0 ... I don't think the voltage at battery 13.6/8 is an issue seeing I have and electric water pump and my fans were on at the time. This could just be me noticing it now but I will check all the wiring again and go from there. Thanks again for the links!!!!! I suppose I could always run some thicker gauge wire from alt to sw and see if there is less voltage drop through the thicker wire