Engine alarm/Smartcraft issue

[Basketcase]

Hello all. I recently got all the parts needed to connect a SC1000 smartcraft tach to my 175 Optimax (Ser#1B119293). I wanted the gauge for a few reasons. To have an accurate tach, to get alarm info, and the extra data such as temp and water pressure. I'm using a 1 resistor cable, a Jbox with resistor, and the system tach harness from the J box to the gauge.

I've been having what I assume is water pressure alarm occasionally at higher rpms. I've done all the basic steps to rectify water pressure issues that I could justify as maintenance. Water pump, thermostats, poppet valve, clean strainer.

I just got my gauge hooked up so I should be able to get more info on the alarm now. Except...It gives me "error,water pressure sensor". It also gives me this error for the fuel level sensor, oil level sensor, and trim sensor. I never hooked up the fuel, so that's obvious. I noticed that there is not a trim sensor installed, so that is too. The two errors I'd like to figure out are the water pressure and the oil level. Is the oil level it talks about the one in the tank on the motor, or on the boat? There is not a sender on the tank on the boat. This one is not a huge priority.

As for the water pressure sensor, that I want to figure out. Could it be that my sensor is bad and that is why I am getting the alarm and error? The pic below is my water pressure sensor, which I do believe should be the correct one, but maybe it's junk? How can I test this?

[JOE54]

see if hose is stopped up / no sensor in boat tank = no data / may need w/p replacement and yes senor could be faulty or gunked up inside

[Basketcase]

see if hose is stopped up / no sensor in boat tank = no data / may need w/p replacement and yes senor could be faulty or gunked up inside

Ok so the sensor it's looking for is the in boat tank? The one on the motor is just a switch to set an alarm if it gets below a certain point? This makes sense.

As for the water pressure sensor, if the hose was clogged (I checked it, its good) or the sensor was gunked up, would it just give a bad reading? In my case it says "error" and gives no reading at all.

The whole cooling system at this point has been replaced with new OEM parts. Aside from an internal leak, I cant imagine that I actually have low water pressure. I may throw an analog gauge on just for testing purposes.

[JOE54]

good idea

[Basketcase]

I'd still like to get the psi gauge to work on smartcraft. I'm assuming bad sensor at this point, due to "fault" as opposed to a bad reading. Can anyone confirm?

[EuropeanAM]

Double check the EXACT message for that water pressure sensor. Likely a bit different than what you typed... and need to be certain before sending you on a wild-goose chase.

The other faults are "ghost" faults (oil is for a remote tank sensor that doesn't exist in your system, fuel is also not connected, trim is analog currently).

A known-good BLOCK Pressure Sensor would let you determine if the problem is the sensor (quite quickly). Virtually any Optimax V-6 will have one (gray tubing) if built after July 1, 2000.

[Basketcase]

So I turned off the sensors I'm not using. The video below shows what happens. After a few seconds of being on it says "FAULT. Water pressure sensor" Then "FAULT SENSOR" then "CHECK ENGINE".

If the sensor is bad, could this be the cause of my intermittent alarm? The alarm is a solid tone while accelerating at higher rpms. It shuts off as soon as I reduce throttle.

Thanks for the help!

[Basketcase]

I've googled the heck out of this and it really seems like its a bad block pressure sensor. Love to have someone smarter than me confirm my findings :)

[JOE54]

try this for a test remove speed sensor and plug it into wpsi sensor, just try it

[Basketcase]

try this for a test remove speed sensor and plug it into wpsi sensor, just try it

I thought about that because they "look" the same! Just didn't want to do damage if it isn't. I'll give it a shot. Thanks!

[EuropeanAM]

They are different in that the Block Pressure sensor is a 50 Psi sensor (whereas the Pitot is a 100 psi), but for a SHORT test to confirm it's the sensor that's causing the problem, you should not have any difficulty.

If the fault is gone- replace the sensor.

[Basketcase]

They are different in that the Block Pressure sensor is a 50 Psi sensor (whereas the Pitot is a 100 psi), but for a SHORT test to confirm it's the sensor that's causing the problem, you should not have any difficulty.

If the fault is gone- replace the sensor.

No faults with the sensor swapped. Just shows a zero for pressure which I guess would make sense since it's the wrong range and looking for different signals. Thanks guys. Time for a new sensor.

[JOE54]

[Basketcase]

Used a spare boost gauge from my TDI as a water pressure gauge. Shows about 2 psi at idle and jumps up to 5ish if I raise it even a little. This is just on muffs at low rpm. Wont be able to really test it until I get it on the water again, but at least I know I have water pressure.

[Basketcase]

New sensor installed. Problem 100% solved. Water pressure reads around 17 on the smartcraft at WOT and the boat moves nicely. Thanks to all for the help!