F225txrd high temp/low oi pressure alarm question

[fairdeal]

OK, hope Boscoe & Rodbolt see this

I notice there's another thread going about alarm testing;

coincidentally, I have my own questions!


1. I want to see my "oil pressure alarm" activate.

I have a 220 ohm resistor prepared - but I want to explicitly confirm:

on the harness connector:

I connect the 220 ohms between the orange (5V ECM reference voltage) and the pink/white?



2. Re "overtemp" - I successfully tested the "thermosensor" by replacing it with 2k ohms -

idled for just about 2 minutes before it alarmed.

But with just the "thermoswitch" connectors shorted,

my attention span ran out after seven minutes with no alarm.

Any insights there?



Hoping for, and appreciating, your expertise !

[rodbolt17]

to test the temp requires shorting the thermosensor with the resistor AND shorting a temp switch.

the oil sensor is a bit trickier as you have to set up a series/parallel resistive circuit OR simply place a known good sensor in the circuit and start the motor.

3 wire sensors use a pick off voltage.
means from orange to black there is a resistor,the pink carries a pick off voltage.
the ECU monitors both the orange wire voltage and the pink wire voltage.

[fairdeal]

to test the temp requires shorting the thermosensor with the resistor AND shorting a temp switch.

So I lucked into it!
I tried shorting the temp switch first, no result - then moved on to the resistor on the sensor
While "forgetting" to go back and reconnect the switches

the oil sensor is a bit trickier as you have to set up a series/parallel resistive circuit OR simply place a known good sensor in the circuit and start the motor.

OK I'm totally lost - with both of those

3 wire sensors use a pick off voltage.
means from orange to black there is a resistor,the pink carries a pick off voltage.
the ECU monitors both the orange wire voltage and the pink wire voltage.

So how do I set up this series/parallel circuit?

[boscoe99]

[fairdeal]

"Crystal" !

Thank you, sir.

(now I need to grab that before it goes away)

[rodbolt17]

bet you did not READ TEST harness part number.

its nessasary, you CANNOT simply unplug the connector and short the two wires.
the ECU will see its unplugged or open circuit.

the oil sensor is a potentiometer.

it has a resistor orange to black.

the pink wire is a picked off voltage dependant on where the wiper is.

[fairdeal]

By the way, while playing with the alarms, I was able to "see" the values on my Garmin via N2K.

With the 2 k ohm on the thermosensor, the gauge read just under 250 F


Not being certain about where to put the resistor for the oil pressure sensor,

all I tried was unplugging it at idle -

the ECM reported ~900 psi - and had no problem with that!

[rodbolt17]

had you tried to run it normally you most likely would have had an alarm.
the oil pressure is set up on a map and the ECU looks at oil pressure vs RPM.

it can and will set the audible for either loss of oil pressure for that RPM or to much oil pressure for that RPM.

[fairdeal]

bet you did not READ TEST harness part number.

its nessasary, you CANNOT simply unplug the connector and short the two wires.
the ECU will see its unplugged or open circuit.

the oil sensor is a potentiometer.

it has a resistor orange to black.

the pink wire is a picked off voltage dependant on where the wiper is.

I did see the "harness" box on Boscoe's chart - "magical thinking" let me completely ignore it...

So - "series / parallel" - just like you said earlier - got it, now





Well I'm certainly not going to buy that "special tool"

Now I have to decide if I want to cut those leads and permanently crimp in female bullet connectors...a bit more of a project than the temperature sensor.

[rodbolt17]

freaking WHY.
simply pull the lanyard sometimes, crank the motor and listen.
yes Virginia that's all ya gotta do.

[fairdeal]

freaking WHY.
simply pull the lanyard sometimes, crank the motor and listen.
yes Virginia that's all ya gotta do.

haha

Rodbolt - you're a good man. I hope you get to retire -

and when you do,

you, too, will need something to occupy your time!!!

[rodbolt17]

occupy time.
I collect and shoot antique military weapons,8mm,7mm,8x50,8x56RS,8x56 lebel,7.5x54,.41swiss,30-06,.303,7.62x39.
plus I shoot cowboy action.
I also shoot combat pistol action when time permits.
I hand load most my ammunition.
I also like to partake in a cool refreshing beverage that shuts down the loading bench.

so between side work on crab boats,shooting and loading and real work I stay a bit busy.

back to your alarm testing.

simply find a used oil pressure sensor.
plug it in and let it dangle.
start the motor.
you can use any v6 4 stroke sensor.

[fairdeal]

simply find a used oil pressure sensor.
plug it in and let it dangle.
start the motor.
you can use any v6 4 stroke sensor.

brilliant - thanks, again!