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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » Help with Engine coolant temp

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Author Topic: Help with Engine coolant temp
Posts: 2
Post Help with Engine coolant temp
on: August 4, 2013 (GMT)

I have a 2001 ford f350 powerstroke and I am having an issue with the Engine Coolant Temp pid. The original formula in the app always read -40. The current formula I am using ( found it on a forum) is the one where you have to subtract the 127 until the temp reaches 127. It is:
It is giving me a reading of 179.5 after 16 hour cold soak. When you subtract the 127 it leaves me with only 52.5 while EOT is at 79.2 and Trans fluid is at 84.4.
Is there any way to get this straightened out? New formula or tweak the existing formula? Any help would be great. Also, I really love the app. It’s amazing!

Posts: 2926
Post Re: Help with Engine coolant temp
on: August 5, 2013 (GMT)

Would you post some raw values of variable A
at known temps like cold, midway below
and above 127°F and at hot temps?

Is there a linear response to coolant temp

Would you also post a test response for
221139? (It may be a two byte response)


Posts: 2
Post Re: Help with Engine coolant temp
on: August 5, 2013 (GMT)

Capp777, thanks for responding but I am going to need a little help here with what exactly you need me to do. I am new to all this. I’m trying to get the stuff I need working on the app to monitor my truck so I can keep an eye on things. Sorry for the “ignorance” but I am trying to learn. I can get some ECT readings (after warm up) from the app for you tomorrow morning if that will help.

Posts: 2926
Post Re: Help with Engine coolant temp
on: August 5, 2013 (GMT)

Not a problem… If there is something
you don’t understand I will try to explain
if I can.

Since you are new at this I would like to
warn you about…

Some 7.3’s have been known to experience
problems with their ecus with certain OBD
diagnostic commands causing engines to shutdown
while driving! So please test your PIDs with
engine off key on until you know its safe.
(forgive if you are aware of these facts already
or if your engine size is different).

That said… 221139 doesnt respond on some
7.3’s. I am curious if variable A is being used
in some non-standard way or does it provide
an increasing linear response from cold to
hot which can be modeled with a slope intercept

There is another PID (22114D) which may
also work for you. It is the coolant temp sensor
input in Volts. If it works for you – maybe able to
model this if the other PID doesnt work.

When you create an extended PID there is a button
on the bottom of the editor screen which will test
the PID for a successful response. This is the test
response data I mentioned above.

Looking at the raw data at known temps will
hopefully answer these questions.


Please read… (page 1 maybe useful as well)

Posts: 6332
Post Re: Help with Engine coolant temp
on: August 6, 2013 (GMT)

There is a ‘SIGNED(xxxxxx)’ function that may be of use in this instance

Posts: 6
Post Re: Help with Engine coolant temp
on: September 17, 2013 (GMT)

Do you have a manual or an automatic transmission? The manual has the trans temp, the auto doesn’t. Basically ford only used a set number of inputs for the 7.3. On the auto they used the Engine Coolant Temp connection for Transmission Temp.

Auto Hobbyist. Currently working on a 7.3 Power Stroke Diesel. I have been working on cars off and on for about 30 years. I am on active duty and I move around a lot so the truck is handy.

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