Ford's FAKE Oil Pressure Guage
#46
12-23-2014, 11:51 AM
Just to add to what Steve wrote, I monitored the oil temperature for a short time after I first installed my Gryphon programmer. I was astonished at the wild swings it would go through depending on engine load. I finally decided it was somewhat pointless to monitor it and stopped doing so.
You may know this, but the Coolant Temperature gauge is pretty much the same as the oil pressure thing. First of all, coolant temperature isn't really monitored at all, but is inferred from the Cylinder Head temperature (which is a better thing to monitor since it's not fooled by steam). However, that temperature "gauge" just goes to a set point and stays there as long as the cylinder head temperature is within a rather wide operating range. Since I can monitor the actual temperature on my Gryphon, I do, and see it vary between 195-226, again depending on engine load and outside temperature. The dash gauge doesn't move at all during these swings.
- Jack
You may know this, but the Coolant Temperature gauge is pretty much the same as the oil pressure thing. First of all, coolant temperature isn't really monitored at all, but is inferred from the Cylinder Head temperature (which is a better thing to monitor since it's not fooled by steam). However, that temperature "gauge" just goes to a set point and stays there as long as the cylinder head temperature is within a rather wide operating range. Since I can monitor the actual temperature on my Gryphon, I do, and see it vary between 195-226, again depending on engine load and outside temperature. The dash gauge doesn't move at all during these swings.
- Jack
Steve
#47
12-23-2014, 12:07 PM
Unless I'm mistaken the CHT sensor does actually measure coolant temp but it does it via a water passage in the head which provides a better and more accurate reading rather than the old way which would have put it in the intake manifold or thermostat housing.
Steve
Steve
I just know the gauge on the dash is not really a "gauge".
While we're on the subject, the voltmeter gauge doesn't appear too useful either. It seems to stay in the same position as long as the voltage is above battery voltage.
So, the only real gauge is the fuel quantity gauge. We would probably be better off with idiot lights.
- Jack
#49
12-31-2014, 11:24 AM
No, really only the tach and speedometer are real and even at this rate I'd be wary of the real story behind those, too. Even the fuel gauge moves in spaced increments. Why else would you have a half-tank left at the obvious midway point (supposedly) and then still have about 4-5 gallons at the empty mark and low fuel light? I get the idea behind early warning, but still...fake.
Last edited by AlfredB18; 12-31-2014 at 11:27 AM.
#50
12-31-2014, 12:25 PM
Yeah, I'm starting to wonder about all the "gauges" too, even the speedo 
I was already suspecting the voltage gauge before I found this thread, it seemed to be always just in the middle when running with no fluctuation.
On the coolant temp however, it was pretty cold the other day ( -35 or so ) and I noticed the CHT did seem to be moving linear fashion as the engine warmed up from way too cold to still not very warm and stayed below where it usually sits when the engine is warmed up in warmer weather. So maybe it is a bit more than just an idiot light. Maybe
I was already suspecting the voltage gauge before I found this thread, it seemed to be always just in the middle when running with no fluctuation.
On the coolant temp however, it was pretty cold the other day ( -35 or so ) and I noticed the CHT did seem to be moving linear fashion as the engine warmed up from way too cold to still not very warm and stayed below where it usually sits when the engine is warmed up in warmer weather. So maybe it is a bit more than just an idiot light. Maybe
#51
12-31-2014, 02:39 PM
Yeah, I'm starting to wonder about all the "gauges" too, even the speedo
I was already suspecting the voltage gauge before I found this thread, it seemed to be always just in the middle when running with no fluctuation.
On the coolant temp however, it was pretty cold the other day ( -35 or so ) and I noticed the CHT did seem to be moving linear fashion as the engine warmed up from way too cold to still not very warm and stayed below where it usually sits when the engine is warmed up in warmer weather. So maybe it is a bit more than just an idiot light. Maybe
I was already suspecting the voltage gauge before I found this thread, it seemed to be always just in the middle when running with no fluctuation.
On the coolant temp however, it was pretty cold the other day ( -35 or so ) and I noticed the CHT did seem to be moving linear fashion as the engine warmed up from way too cold to still not very warm and stayed below where it usually sits when the engine is warmed up in warmer weather. So maybe it is a bit more than just an idiot light. Maybe
As for the temp gauge, it is more than an idiot gauge, not much more but it is.
-Steve
#52
12-31-2014, 05:11 PM
Interesting what you say about the speedometer. My speedometer appears to accurately reflect any speed I'm driving when I compare it with the readout that my GPS gives me. Of course it reads about 2% higher than the GPS, but that seems to be just an anomaly of converting digital data from the PCM to an analog readout. The Tach seems pretty close too.
My fuel gauge is like what I've seen in most vehicles. No movement at all from full for the first 50+ miles, then it drops fairly smoothly over the rest of the range. I think it goes down at a faster rate though in the last half tank range. And, the low fuel warning seems to come on with about 3 gals remaining (and the needle is still slightly above the "empty" mark).
And I know the temperature gauge will suddenly "peg" if the engine overheats, but I don't really think that's the way a true gauge should behave.
- Jack
My fuel gauge is like what I've seen in most vehicles. No movement at all from full for the first 50+ miles, then it drops fairly smoothly over the rest of the range. I think it goes down at a faster rate though in the last half tank range. And, the low fuel warning seems to come on with about 3 gals remaining (and the needle is still slightly above the "empty" mark).
And I know the temperature gauge will suddenly "peg" if the engine overheats, but I don't really think that's the way a true gauge should behave.
- Jack
#53
01-02-2015, 09:19 AM
Some speedometers are more accurate then others but very few are dead on accurate, the average seems to be about 3-5% fast. A magazine compiled a bunch of test data a few years back and that's what they found.
I know the speedo in my car reads about 5% over actual at around 70 mph. So at a true 70 my speedo is showing 73-74 mph.
-Steve
I know the speedo in my car reads about 5% over actual at around 70 mph. So at a true 70 my speedo is showing 73-74 mph.
-Steve