Perko to DECC is good enough?

[toyotafreak]

Finally ran fused 8 gauge wire (red & black) from the Perko switch to the dash. Is it sufficient to cable it into the DECC terminals? Early TMS documentation suggested bringing thicker wire all the way to the dash computer (MMDC?). Thought I saw from some forum members that DECC was sufficient.

Thanks!

[wakejunky]

Are you trying this to get more accurate guages?

[toyotafreak]

Fewer low voltage alarms, etc. Gauge performance, basically.

[wakejunky]

the ground wire wont hurt, but the power wire is only going to make the problem worse. Its basically an electrical interference problem. Ive been working on this all winter and Ive managed to make some real progress with this. its not perfect but its a lot better. believe it or not several boats including ours were Guinea pigs for the automotive industries new standards that were being pushed by big brother. its called CAN "controller area network". they started putting the system into cars as early as 2005 and my 2008 its required. it caused real havoc at first when it first came to cars. we have a dinosaur version in our boats. basically all gauge information "electrical" is going down a single wire and it runs up to 5 volts. everytime we add another power wire along the main harness down the drivers side we just get more and more electrical interference. add it all up and a 1 volt signal can turn into 3 volts and that can push a temp reading of 170 degrees to 205 degrees really quick. see how bad all your gauges work when you turn on all your accessories at the same time. could never figure out why my boat overheated at the end of the day? it was 5 rule 1100 gph pumps + stereo + dash lights + docking light+ etc. it adds up quick. Even if you dont have a lot of add ons on the boat Toyota made no effort to isolate the signal wire from high voltage wires right next  to it. its exactly like laying RCA cables right next to 2 gauge amp power wires.

this is what Ive done so far. removed all unnecessary high voltage wires. moved the gauge computer from behind the back seat next to the motor and reinstalled it under the dash, its all plug and play wiring, you just have to move the computer. i was able to remove almost 12 feet of unnecessary factory wiring and i saw and immediate difference the first time i took the boat out. with all the same accessories on as i use to have when it would run 205 degrees it now runs at 185 degrees. i havent had much time to work on it lately so that's where I'm at.

[toyotafreak]

Thanks for the info. I had no idea. On the other hand, it's hard for me to imagine that 14VDC direct from a battery could cause interference. I can imagine crosstalk between signal wires, but vanilla 12VDC? I can imagine there's a difference between how your cimputer was so far removed fromt he gauges as compared to the V-drives which are already under the dash.

On the fake a lake today, I ran the boat without and then with the fuse installed on the new second line. Only really watched the reported voltage and didn't see a big different at idle. Guess I wouldn't expect to with no real draw from the gauges, etc. like we see at higher throttle settings (that's when the alarms usually happen).

Will be out on the lake this weekend (yeah!!!!!) so may try with and without to se a difference. Will report back.

[lesman01]

Running the 8gauge ground wire fixed my hi temp problem, but i still get low voltage and oil pressure alarms constantly. have for many years now.

[toyotafreak]

Nice weekend, but being a bachelorette chaeffeur did not allow me to spend a bunch of time tooling around. Never got the alarm and hit WOT by myself one afternoon (43 mph and 5500 rpm, a bitoverpropped, huh?) without alarms, but just don't recall if the low voltage alarms were occasional or frequent 2.5 years ago... Not sure if my 8 gauge helped or not.

Boat ran real nice. It turned ten this march and has picked up some war wounds, but for the most part looks just supersweet. Long live the Epic!!!

[brad]

Replacing the oil sender unit has eliminated the low oil pressure alarm on my boat.  Just replaced it for a second time in last 8 years.

[svlkid]

Did you replace it with one you bought here or is it an automotive part? I need one for this weekend or I would just order from Rick.

[svlkid]

We get a chirping sound at idle. Is that low voltage or low oil pressure? I thought temp and oil pressure were the only alarms. I have a '99 direct drive.

[sailtl]

Change the oil pressure sender. I am about to order my 3rd one in 10 years.

[brad]

I replaced mine with one from the Parts section here as well as an aftermarket one.

[svlkid]

Was there any difference? What aftermarket one did you use?

[brad]

I ordered it from iBoats.com

Oil Pressure Sender - Sierra 18-5899 - $22.49 plus Tax, S&H

Been out several times since I've replaced it and no low pressure alarms.

[toyotafreak]

Update from the front... the 8 gauge power and ground cables from Perko to DECC did NOT solve the low voltage alarms. To clarify, these alarms pop up on the message center when voltage frops below some really low level. It happens at high throttle/speed settings ehich I though was related to the amount of juice the Medallion gauges draw. What I noticed this trip is that as soon as I turn on the Nav/Anchor and transom lights, the alarm sets at MUCH lower settings, like steady 32 mph cruise. It gets annoying because it makes my depth finder readout go away, and dusk through the shallows is when you need the depth finder most.