Fan speed question.
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From: Center, Texas
Fan speed question.
I have been monitoring my fan speed some since its been getting hotter outside (mid 90's) and up until a couple of days ago normal highway driving it would be around 400+ and would only go up if the coolant temp hit around 206-207 and id see the speed spike to around 1600. I do have slightly higher than most coolant temps which hover around mid to high 190s up to around 207 or so but sustained is about 196-202. I had noticed at idle at redlights the fan speed would climb to 12-1500 but thats having the a/c on also and I dont know how much that factors in. Well the last couple days with my coolant temps still being low 190s it will spike up to around 1500 or so and come back down to around 450ish and then climb again just at random. Could the A/C play that big a factor in it along with the outside temps or could I have a sensor going out. I do have my egr deleted via the stealth way (plugged ends) but my egr valve is still plugged in as to not mess with the pcm. I have an 05 later year but the egr delete has never thrown a cel. Thanks.
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Higher ambient temps and the A/C creates a lot more heat.
Winter I will see ECT 190-192 all day long no matter what.
ONce the temps start hitting 80 and especially now with 95+ sitting at a really long stoplight my ECT will creep up to 198.
At the stoplight and A/C on I'll notice around 800 fan rpm which will ramp up 1500+ (55%+ duty cycle) once the light turns green and then slow down to the 1100 range while cruising at say 40 mph.
The fan duty cycle goes to 0% at 50 mph.
Not long after the light turns green and the truck is cruising the ECT comes back down to about 194, takesa bit longer for the EOT to come back down and by then there will be another redlight etc.
On the highway it's about 192-194 ECT with ambient 95+.
Josh
Winter I will see ECT 190-192 all day long no matter what.
ONce the temps start hitting 80 and especially now with 95+ sitting at a really long stoplight my ECT will creep up to 198.
At the stoplight and A/C on I'll notice around 800 fan rpm which will ramp up 1500+ (55%+ duty cycle) once the light turns green and then slow down to the 1100 range while cruising at say 40 mph.
The fan duty cycle goes to 0% at 50 mph.
Not long after the light turns green and the truck is cruising the ECT comes back down to about 194, takesa bit longer for the EOT to come back down and by then there will be another redlight etc.
On the highway it's about 192-194 ECT with ambient 95+.
Josh
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From: Center, Texas
Now that you mention it Josh, itll be 8-900 until I take off from a redlight and go up to 1600ish and come back down. I tried putting the duty cycle xguage in the scanguage but I never could get it to work. I guess Im noticing it more because of the a/c being on. Thanks to both of you for putting me at ease. I wasnt too worried since Im cooling ok but being cautious since it had changed pattern recently. Thanks again.
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Now that you mention it Josh, itll be 8-900 until I take off from a redlight and go up to 1600ish and come back down. I tried putting the duty cycle xguage in the scanguage but I never could get it to work. I guess Im noticing it more because of the a/c being on. Thanks to both of you for putting me at ease. I wasnt too worried since Im cooling ok but being cautious since it had changed pattern recently. Thanks again.
I also notice a difference in the fan behavior in a/c-off versus normal a/c and max a/c. The fan ramps up and down speeds a lot more on max than normal and the fan hardly does anything with the a/c off.
I also noticed just having the A/C active adds about 3-4 degrees to ECT with all other variables the same i.e. ambient temps and driving conditions.
That's the side effect of using these digital gauges, it has the potential to turn someone into a hypochondriac.
Josh
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From: Spanaway
The PCM takes into account a lot of things in it's request for the fan to run or not.
The A/C (ON/OFF) is one of the things that it looks at. The rest of the list I have somewhere
and at the moment I can't find it. I think it is also the BARO, Air temp, coolant temp, oil temp.
But I am guessing and.......
Sean
The A/C (ON/OFF) is one of the things that it looks at. The rest of the list I have somewhere
and at the moment I can't find it. I think it is also the BARO, Air temp, coolant temp, oil temp.
But I am guessing and.......
Sean
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Watching live data flow can be scary at first the pcm is constantly adjusting things makeing a minor adjust ment here and there according to the information it receives from its sensors. This happens all the time you just never saw or head or felt it before, when its a normal small adjusyment there is nothing to see hear or feel. But now you are seeing it electronicly as it happens volt by volt, degree by degree. Quiet scary isn't it. LOL
In the case of fan speed when you stop you aren' generateing as much heat but you also decrease the air flow from losss of movement thru the air, fan speed increase slightly to compensate coolant temps drop.
You take off more heat is generaated requireing more air flow to disipated.
Increase in forward motion does not quiet generate enough airflow so fan speed is increased to compensate and the cycle goes on.
In the case of fan speed when you stop you aren' generateing as much heat but you also decrease the air flow from losss of movement thru the air, fan speed increase slightly to compensate coolant temps drop.
You take off more heat is generaated requireing more air flow to disipated.
Increase in forward motion does not quiet generate enough airflow so fan speed is increased to compensate and the cycle goes on.
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Tuned
Joined: Jan 2009
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From: Newnan, GA
All of the above.
Plus I have noticed after engine is warmed up and I make a short stop, engine off, the fan goes to high mode for a minute then back to normal mode of operation.
After extended towing and watching the fan speed changes I found out;
At ECTs of 209 deg......fan goes to mid speed range
At ECTs of 219 deg......fan goes to high speed range
Otherwise at temps below 209 the fan varies in speed 400-650ish depending on engine RPM.
Just my 2 cents worth
Plus I have noticed after engine is warmed up and I make a short stop, engine off, the fan goes to high mode for a minute then back to normal mode of operation.
After extended towing and watching the fan speed changes I found out;
At ECTs of 209 deg......fan goes to mid speed range
At ECTs of 219 deg......fan goes to high speed range
Otherwise at temps below 209 the fan varies in speed 400-650ish depending on engine RPM.
Just my 2 cents worth
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The PCM takes into account a lot of things in it's request for the fan to run or not.
The A/C (ON/OFF) is one of the things that it looks at. The rest of the list I have somewhere
and at the moment I can't find it. I think it is also the BARO, Air temp, coolant temp, oil temp.
But I am guessing and.......
Sean
The A/C (ON/OFF) is one of the things that it looks at. The rest of the list I have somewhere
and at the moment I can't find it. I think it is also the BARO, Air temp, coolant temp, oil temp.
But I am guessing and.......
Sean
Josh
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Joined: Apr 2012
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From: Charlotte, NC
I could've sworn I've read on here that high EOT will trip the fan speed, but I'd have to look to find the source. Regardless, my ECTs will ususally be climbing if EOTs are too, i.e. when towing. Gonna be watching the temps on my July 4 trip to the Boone, NC mountains.
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I could've sworn I've read on here that high EOT will trip the fan speed, but I'd have to look to find the source. Regardless, my ECTs will ususally be climbing if EOTs are too, i.e. when towing. Gonna be watching the temps on my July 4 trip to the Boone, NC mountains.Josh
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Posting Guru
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From: Virginia beach, VA
You might want to check for codes. I have a P0528 fan code which never triggered the CEL. My fan clutch is bad and if I idle for a few minutes with the a/c on on a hot day, when I start driving again the fan is roaring away.
Unfortunately, I couldn't tell you my fan rpm's because the Edge can't monitor half the things that a scangauge can
Unfortunately, I couldn't tell you my fan rpm's because the Edge can't monitor half the things that a scangauge can
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Josh
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