Coolant Temp sensor issues?

[MtnOilRIG]

Anyone know the symptoms for a bad coolant temp sensor? I do not get a reading from my Scan Gauge II, should I be getting one? I get an ambient air temp reading but it is blank where there is normally a coolant temp reading.

Temperature gauge reads fine, I get a low coolant light occasionally under heavy load, but the the coolant level is fine when I check it. I run ELC, have a coolant filter, 203 therm, new water pump and billet housing and burn VO thru a separate heated system/tank.

Truck is a 2002 F350 7.3l cclb w/ 227k

Reason I'm asking is that I have a fuel temp gauge (both diesel/VO) that rose to 244deg on a long pull up a pass and I am wondering why my Ford coolant temp gauge never moved from its normal operating place during the whole run. My fuel temp should not be higher than my coolant temp the way I understand it. This was the second run up the pass with my winter bra on, but was thinking I could watch the Ford temp gauge to ensure I wasn't overheating. Do the Ford gauges work?

I posted over in the Biodiesel forum but have had no interest or help. here -->How hot is too Hot?

Thanks in advance,
oZ

[duck fan]

The PCM does not monitor coolant temp on an automatic tranny truck. Similarly, it does not monitor oil temp on a manual tranny truck. So your scnaguage won't return a value or it won't return an accurate value for coolant temp.

That being said, if you are overheating there should be some movement in the dash gauge, also you should have boil-over of some sort.

[MtnOilRIG]

That is reassuring as I had neither gauge movement or boil over, and the truck kept pulling like a train all the way to the top. Drove an hour that night and 4 hours the next day with no issues.

Does the gauge start moving from normal operating at a certain temp or gradually? Anyway to test the gauge and make sure its working on the high end? It seems to work as the truck is warming up.

I have no idea how I could get 244deg at my fuel manifold when the engine's coolant temp is the only thing that builds heat in my VO system (heater core, FPHE, hot fox and back). If the coolant was 244deg, I would think the Ford gauge would be pinned.

I'll be trying the pass next time without the bra, but it still makes me think it could be overheating at the beginning of the VO loop (first place coolant exchanges with the oil and where fuel temp sensor is), exchanging heat into the VO through the whole loop and returns normal-ish temp coolant into the water pump where the temp sensor is??? Showing the truck is running at a normal temp, when the engine is much higher in temp.

I'm confused. and I know this is more an alternative fuel discussion, thanks for your help with the PCM and temp sensor info. I will be trying to figure this one out as I don't want to be ghost overheating my rig.

oZ

[jesilvas]

Originally Posted by duck fan

The PCM does not monitor coolant temp on an automatic tranny truck. Similarly, it does not monitor oil temp on a manual tranny truck. So your scnaguage won't return a value or it won't return an accurate value for coolant temp.

That being said, if you are overheating there should be some movement in the dash gauge, also you should have boil-over of some sort.

What how why?
I was reading that earlier today, and I understood it as the PCM "decides" what the ECT is based off EOT?

[duck fan]

When I was having overheating issues with my truck 2 summers ago, the gauge would gradually move up.

[MtnOilRIG]

Wondering what ECT and EOT are? Sorry for my ignorance.

Then I should be getting a reading from my coolant temp sensor?

[duck fan]

Originally Posted by jesilvas

What how why?
I was reading that earlier today, and I understood it as the PCM "decides" what the ECT is based off EOT?

A better way to say it is that it infers it based on the data it monitors. Why did Ford do it that way? The world may never know. Why does it monitor EOT on autos and ECT on manuals? Again, the world may never know.

Originally Posted by MtnOilRIG

Wondering what ECT and EOT are? Sorry for my ignorance.

Then I should be getting a reading from my coolant temp sensor?

ECT - Engine Coolant Temp

EOT - Engine Oil Temp

You should be getting a reading on your scanner from your EOT if you have an automatic or your ECT if you have a manual.

[late_99_PSD]

I have a manual and I can read EOT and ECT with a scanner. Well at least I could the last time I had a scanner hooked to it

[TDIer4life]

Thanks to 505live on TheDieselstop for the info;

I found the codes to get coolant temp for my 7.3L out my Scangauge II xgauge:

TXD: C410F1221139
RXF: 046205110639
RXD: 3008
MTH: 00010002007F
Name: ECT

Here's the catch, and why I don't think scanguage advertises the code: The signal changes resolution part way through the warm-up and the math can't be triggered to change with it. It's really simple tho, below 127F it reads 2x the temperature, so as the vehicle warms up the reading is double until it reaches 127F. I.e., during w/u the gauge will read up to 254, then when crosses 254 it will switch to actual temp and drop to reading to the "actual" 127F, after which it remains accurate.
I punched this one in this morning, and verified it works on my xgauge.

[late_99_PSD]

Oh, its one of THOSE types of ECT senors

Good info