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BF150 Temperature Sensor Trip Points

P

PaulBF150

Contributing Member
Of the 4 Temp Sensors
Cylinder Head
Cylinder Block
Exhaust
Engine Case

What temps trigger the ECM to alarm? Which one causes the ECM to Alarm and subsequent shutdown motor?

I am monitoring each with A/D converter into a computer.

Paul
 
PaulBF150 said:
Of the 4 Temp Sensors
Cylinder Head
Cylinder Block
Exhaust
Engine Case

What temps trigger the ECM to alarm? Which one causes the ECM to Alarm and subsequent shutdown motor?

I am monitoring each with A/D converter into a computer.

Paul
Click to expand...
Did you ever find out this information paul? I have a 2005 bf150 with some temperature problems and I would certainly like to know this information.
 
whalerpaul said:
Did you ever find out this information paul? I have a 2005 bf150 with some temperature problems and I would certainly like to know this information.
Click to expand...
Nobody has responded that I've seen yet with that information. I'm doing some separate investigation trying to figure out how all this works. Since we probably have the same outboard motors it sounds like a good idea to be in closer communication. How do we go about sending private messages on this site?
 
If it is of any use to anybody, I would be happy to post the pictures of where I have found temperature sensors on the 2005 Honda bf150
 
Just reviewing overheating this thread. I have been going with the exhaust sensor too, but previously I triggered each sensor to over heating point, but forgot the result. I think I had anyone one of then cause the shutdown. The past year I was addressing exhaust overheating, and now since boat is in my shop I can reconfirm. I will be putting in a new post regarding water scoops to grab more water into engine since I amstill overheating.
 
All temp sensors will trigger alarm and guardian if an overheat event is detected. The only way to see which one is with the use of DrH and monitor temps on each sensor underway
 
iang6766,
I found that all sensor expect the Case triggers the alarm and subsqently engine shut down. Much of the is addressed In my BF150 Overheating Continued posting.

In using Dr H application, the tripping point is about 160 degrees F. for cylinder head and exhaust. Dr H does not monitor Cylinder Block. There are 3 sensors that Dr. H monitors (Sensor 1 is the Case, Sensor 2 Head, Sensor 3 Exhaust). I connected a resistor box to each sensor input to the ECM and dialed down the resistance until the alarm while monitoring Dr H.
 
EBT is block temp and that is the temp reading you get on the NMEA network and it is definitely montored by the ecu.and is triggered at 110 deg C
 
As I just posted in the other thread Dr H reports 160F, so I could fake the ECU out with more resistance, rather that replacing the ECM.
I am told IR thermometer are inaccurate so I need to hook up my thermal couple meter and see what temps I can achieve. I been recirculating the water into the engine that gets hotter and hotter (although my submersible pump gave up early, but I fixed that ).

I don't have a NEMA network.
 
Be very careful of "tricking" the ecu. A customer of mine did this by hanging a temp sensor on the outside of the engine, he completely destroyed the powerhead powerhead with a catastrophic overheat. You can buy relatively cheap engine temp monitors with stick on sensors which you can place where ever you want and are very accurate. I would take this route before taking drastic actions to keep the engine running without the guardian
 
Got it!
Puzzled that you said typical alarming temperature is 230F. And my Dr H indicates 160F.

So, I guess the best place to monitor actual water temp is the outlet on top of the engine where the 2 thermostats are located? OR should it be the water coming out of the top of the exhaust manifold? So, you will say why not both!!

Just to make sure recycling the water in a 55 gallon drum back into the engine via a sump pump is okay? Since I am doing that now.
 
The block temp is the highest on the engine, next to the oil pressure sensor.I'm only trying to help. If you had a nmea2000 compatible engine, normal running temp when it's reached it, takes about 20min at WOT. from experience on many 135 and 150 motors, this typically sits in the mid 90s C
 
Now since you mention it, I thought the sensor next to the oil sender was the case temp sensor. When I fooled the ECM for this sensor I could achieve nearly 230F (on Dr H) and no alarm) .Since this engine has 2 sensors on top of the engine associated with the 2 thermostats. The Block Thermostat is the 60C one and below it is the temp sensor. Same goes for the Cylinder Head 50C themo and sensor below it.
 
Bottom-line

Tested both engines with Dr H and Thermocouples in exhaust water output and water output from combined Cylinder Head/Block. In around 155F reading from thermocouple and Dr H reports 158F

Engine alarms and subsequently shuts down. So, both engines computers are responding the same just that Starboard engine gets to 160F faster than the Port Engine.

So, I guess I could try faking engine say 10F such that it may extend shutdown point but increases overall head temp.
 
iang6766 said:
EBT is block temp and that is the temp reading you get on the NMEA network and it is definitely montored by the ecu.and is triggered at 110 deg C
Click to expand...
PaulBF150 said:
Bottom-line

Tested both engines with Dr H and Thermocouples in exhaust water output and water output from combined Cylinder Head/Block. In around 155F reading from thermocouple and Dr H reports 158F

Engine alarms and subsequently shuts down. So, both engines computers are responding the same just that Starboard engine gets to 160F faster than the Port Engine.

So, I guess I could try faking engine say 10F such that it may extend shutdown point but increases overall head temp.
Click to expand...

iang6766 said:
That's correct, I just haven't worked out how they achieve 90 plus in the block with a 60 deg thermostat, but they do
Click to expand...
Here's my take on that: the thermostats for the head and block remain closed or partially closed from below 140° F to about 160°f ...this ensures that the engine will not be running cold and lets it heat up quickly. Above 160°. The thermostats then have basically no further impact on the temperature regulation.. they can't open up anymore than they are. I can imagine that the engine will tend to generate more heat at higher RPMs, but this is kept in check by the impeller pushing much more water into the engine as the RPMs increase.
Above some high RPM, I'm guessing above 4000 or 5000 RPMs, it is possibly too much water coming through and there is apparently a need to limit the amount of cooling water sent through the engine and this is where the relief valve opens up and dumps some water into the exhaust system. It must have been an interesting engineering problem to get the force of that relief valve spring just right:)
 
I'm still trying to understand the valuable information that is being shared here and would appreciate Paul's and Ian's comments as to whether the following statements are true or not for the Honda bf150.

1. There are four temperature sensors any of which can trigger Guardian mode. Two are located by the two thermostats on top of the engine, one on the exhaust manifold, and one on the case/block near the oil filter.

2. The first three of these temp sensors trigger Guardian mode around 160° f. The fourth sensor by the oil filter triggers near 230 degrees Fahrenheit.

3. The normal operating temperature near this 4th sensor is about 205°, (96° C) . Plus or minus a few degrees.

4. Paul, when using Dr h, is only able to see the temperature of the first three sensors, not the one by the oil filter. Ian , with his Nema capability can ONLY see the sensor by the oil filter, apparently called Block temperature.

5. There appears to be some confusion because the temperature sensor by the 60° C block thermostat on top of the engine is called a block temperature sensor and the sensor by the oil filter is termed the case temperature sensor or the EBT (Engine Block Temperature?). I think the explanation here is that both of those sensors measure temperature in the block but at different locations.

6. The hottest temperature that will be measured in the engine by the current sensors will be at the sensor near the oil filter. Note the guardian triggering temperature in item number two above.

7. Once the triggering temperature at the sensor is reached the engine will go into Guardian / limp mode with RPMs dropping to 2000 or below and the engine imitating a heavy coughing mode.

8. In some unspecified amount of time the engine will quit. If you turn the key off and then back on again to start the engine when you were in Guardian mode, the engine will start normally and for a short period of time will run normally until it enters Guardian mode again, especially if you try to achieve high RPMs.

Any comments on these items or my recent attempted explanation of how the relief valve works would be greatly appreciated.
 
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