Voltage to pcm

[1ranger487vs]

How can check the voltage is good to pcm. I have 12.8 at the starter but I’ve been getting a low voltage alarm on my garmin units. Engine ran bad last time out. Just started looking at it. Had surgery recently so have to take it easy for awhile. Looking at that before I unhook anything. Wondering if I have a bad connection or corrosion somewhere. Next on my list is air fuel pressure. I did smell some gas fumes idling at launch but no obvious leaks. Air rail didn’t have gas in it when I pressed the valve. When engine is running I see 13.4 on vessel view. Thx
250. 2b112238

[lpugh]

smartcraft or vesselview link or mobilee is the quick easy way

[1ranger487vs]

Not sure what you mean Leon

[FeFanatic]

Garmin is on a completely different circuit. If you have 12.8 volts at the starter then you should have 12.8 volts at the pcm. Leon means that you can get Smartcraft gauges to monitor your motor functions and voltage. I had Garmin on my boat before switching to a different brand and the Garmin units did not match the voltage of my Smartcraft gauge.

[chad202]

If your motor started running bad at the same time you were getting low voltage on your Garmin, and your electronics come off your cranking battery, you either the battery going bad or you have a connection issue at one of the battery post. OR, you could possibly have a short somewhere but I'd lean toward the battery or battery connections.

[SilverFox579]

When engine is running I see 13.4 on vessel view.

VesselView is accurate, and that's low, you should be seeing 13.8v minimum at idle.

[EuropeanAM]

VesselView is accurate, and that's low, you should be seeing 13.8v minimum at idle.

Not necessarily. 13.4 is fine... and Smartcraft reports the LOWER of MPR voltage or PCM Wake voltage.

I do agree that if you have evidence of a voltage problem with ANYTHING that's on the same battery, START THERE. Proper capacity, amperage and voltage are one of the "Cardinal Rules" for the Optimax.

[1ranger487vs]

I’m using one of the recommended batteries from Napa. It’s about 1 year old. When I can I’ll dig into this further. Thx for the help so far.