Originally Posted by BUP

Do you have the proper service manuals to help with diagnostics ? so was power still on when you were changing out sensor(s) and the PCM. hopefully you did not put a known good pcm on the bad engine ??? HUGE MISTAKE to do that. You test the other way around - bad engine PCM on good motor - there is a reason for that keeping known good PCM's alive.

Also code 133 is NOT a fault code anyone thinks it is. Code 133 is the 5 V power low- Meaning this is the 5 V power that supplies all the sensors its 5V reference so that code actually means Excessive current draw on the 5 V circuit in return means sensor(s) and or the circuit shorted to ground. So whats unplug or shorted ?

Just asking is your app DTS ? I do not think it is but still a ?

Originally Posted by BUP

you will need to post both of engine serial numbers. many things change thru out the years with the 496 including the wiring harness. 10 pin went to a 14 pin harness. Also possible on your app one engine might be older than the other. --- I Have no idea unless I was looking at them and or run the engine serial numbers.

Also are the engines totally stock apps ??? If not what is the set up - in detailed info.

from the start of the 496 birth the that last production day end of the 496 Marine side - I prob can list over 100 different things how the 496 changed thru out the years. -- actually easily way over a 100 things changed for the 496 marine application thru out the years.

Originally Posted by AllDodge

The spark with nothing on concerns me, maybe the battery charger

So far as the beeps, I would connect a meter to the 5V circuit, then start unplugging some of the sensors, water pressure, water temp, IAC, TPS and just turn ignition to ON. When the shorted sensor is unhooked, the voltage will go up to 5V

Originally Posted by ShouldBFarmin

So in my 5v system I have 3 volts on the 5 volt line and 2 volts on the ground line . Is it s sensor? Is it a bad ground?
If it was a short in a sensor wouldn't I have continuity on the 5v line to ground?

Originally Posted by AllDodge

The "short" term is meant to indicate something is drawing enough current to drop the reference voltage below the standard or 5V in this case. Same goes with a starter motor and the battery. If the starter pulls more current when cranking the motor, voltage will drop further down. So there is something in the 5V circuit which is pulling more current then normal which is dropping the voltage to 3V, but is not a dea short which would pull down to 0V if not blow a fuse when doing so.

If it was a bad ground the voltage would show full 5V and there would be a code for the bad sensor for not providing the correct range voltage back to the ECM

Originally Posted by ShouldBFarmin

So why is the 2 of my 5v in the ground line and 3v in the 5v grey line?

Originally Posted by AllDodge

The "short" term is meant to indicate something is drawing enough current to drop the reference voltage below the standard or 5V in this case. Same goes with a starter motor and the battery. If the starter pulls more current when cranking the motor, voltage will drop further down. So there is something in the 5V circuit which is pulling more current then normal which is dropping the voltage to 3V, but is not a dea short which would pull down to 0V if not blow a fuse when doing so.

If it was a bad ground the voltage would show full 5V and there would be a code for the bad sensor for not providing the correct range voltage back to the ECM

Originally Posted by ShouldBFarmin

So in my 5v system I have 3 volts on the 5 volt line and 2 volts on the ground line . Is it s sensor? Is it a bad ground?

Originally Posted by NightHawk

If you're measuring that correctly only one thing can cause 2 volts on a ground line and that's a bad ground. Ground should be ground. I'd focus on that..