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Discussion Starter #1
I have never trusted factory gauges and this just confirms it. For all of you that have been worried about strange readings from your oil pressure/temp gauges I can tell you it is a "GAUGE PROBLEM" because there are NO SENSORS anywhere in the car that measure oil pressure or oil temp. The readings on these "GAUGES" are controled by the ECU based on engine speed, water temp, and how hard it "thinks" you are driving and for how long.


I have installed water temp, Oil temp, and oil pressure gauges. The temp gauges are digital and accurate to +/- 3 Deg F at 300 deg, with the sensor for water temp installed in the cylinder head by the thermostat housing, and the oil temp sensor mounted in the oil pan below oil level. The Oil pressure gauge is mechanical and picks up at the oil galley in the side of the block near the oil filter.

When the car is started cold in the morning (water and oil temp below 60degF) at 1000 rpm the car is making 78psi of oil pressure. The factory gauge is showing 1 needle width below the center mark on the gauge.

After I have been out on the track for 20-30 minutes on a 95degF day and the oil temp is at 250degF and the water temp is at 203degF at 1000 rpm the factory gauge reads 1 needle width below the center mark but the real oil pressure is 40psi.


When the engine is above 4000rpm the factory oil pressure gauge reads 1 needle width above the 3/4 mark cold or hot, the real pressure is 80 with cold oil and 60 with hot oil.

The factory Oil temp gauge comes up to just below mid scale within the first 3 miles of driving every morning. At that point the water temp is usually between 160-170degF but the oil temp is only 115-125degF. At 250degF oil temp at the track the gauge is reading 1 needle width above mid scale.

The factory water temp gauge reads mid scale with the real temp between 160-200degF. I have seen as much as 213degF after shutting the car off and stoping the water flow and the factory gauge does not move a full needle width above center.


I was hoping the factory oil cooler would do a better job of controling the oil temp at the track (thank goodness for synthitic oil!!!) so I am thinking about adding a cooler with a thermostat for track use. On the street the oil and water temps are usually within 10deg of each other both in traffic and out on the freeway.

So just to sum it up, The oil pressure and temp gauges are just a fancy way of filing up the coin holder that the non SVT's have and the water temp gauge is not a lot better!!


The one thing I was really worried about was oil surge while at the track (durring hard cornering and braking does the oil slosh away from the pick up for the pump?) And there is NO loss of pressure at any point on the track so Ford did do something right with the windage tray and pickup location
 

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"...The readings on these "GAUGES" are controled by the ECU based on engine speed, water temp, and how hard it "thinks" you are driving and for how long."

So is it over-riding the thermostat, PCV valve sensor etc...?

"I have installed water temp, Oil temp, and oil pressure gauges... installed in the cylinder head by the thermostat housing, and the oil temp sensor mounted in the oil pan below oil level. The Oil pressure gauge is mechanical and picks up at the oil galley in the side of the block near the oil filter."

Where are the stock ones going, they are there and reading something? If there is a thermostat why isn't the stock instument reading off that? If there are oil sensors why isn't the stock guages reading off those, did you just replace or install new aftermarket ones? What brand, model, etc...

I see that you have a very scientific approach to measuring your new instruments to the stock ones. Measuring accurate PSI and Temp is one thing you want, but relating it to needle widths is very hard when is't being measued in unknown variables or incriments.

Can the stock instruments be calibrated? Can they be replaced with ones having numbers and scale to accurately read the values?

I am not sold on your opinion that Ford spends big dollars on engineering and deisgn for somthing that is ultimately fake and only a replacement for a coin tray.
 

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Discussion Starter #3
There are NO oil temp or pressure sensors anywhere on the engine. There is a low oil pressure SWITCH that turns on the idiot light (at 10psi) and no other sensor for pressure ro temp (not only have I looked all over the engine I have also looked at the wiring diagrams and parts lists, they do not show any sensors.

The gauges are there for the GEE WIZ factor and I am sure Ford put them there to sell cars not actually give usefull information.

As far as calibrating them I guess if you could crack the code in the ECU that is sending the signal to the "GAUGES" and teach it to actually look at the sensors (that you would have to add to the engine and wire into the ECU) then you might get some usefull information.

And as far as using "Needle width" to indicate the "READINGS" on the factory gauges, other than the 1/4 scale markings on them all they have no indication as to what their scale is. My only reason for using them is to show that at slightly less than 1/2 scale reading on the oil pressure gauge can mean anything from 40-78psi and that slightly more than 3/4 scale reading can mean 60-80psi. If you turn the engine off and immediatly turn the ign back on without starting the engine, the factory pressure gauge reads ZERO while the mechanical gauge is still showing 30+psi and falling (the low oil pressure light has not come on yet either), and when you start it the factory gauge is up to "normal pressure" before the mechanical gauge up to 30psi.
 

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Where are the stock ones going, they are there and reading something? If there is a thermostat why isn't the stock instument reading off that? ...
It is a mechanical valve controlled by temperature to adjust the flow of water to the radiator. There is nothing to read.
 

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It is a mechanical valve controlled by temperature to adjust the flow of water to the radiator. There is nothing to read.

Temperature is a measure of heat and what mechanical device is interpereting that incrimental change of heat to make a valve open or close. Something has to tell a valve to open or close. Is the ECU telling the valve to open? Where is the ECU getting its information to tell the vavle to open?
 

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So just to sum it up, The oil pressure and temp gauges are just a fancy way of filing up the coin holder that the non SVT's have and the water temp gauge is not a lot better!!
I thought it was pretty well known that the factory guages in the booger bin were just fancy idiot lights.
 

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The one thing I was really worried about was oil surge while at the track (during hard cornering and braking does the oil slosh away from the pick up for the pump?) And there is NO loss of pressure at any point on the track so Ford did do something right with the windage tray and pickup location
At least that's somewhat reassuring.
 

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If the fancy idiot lights work improperly then how do I know if the engine is going to overheat? Do the engine temp sensors go bad or need calibration? Mine will read pegged out max before the fans kick on. I freaked out thinking it was going to overheat and cause damage.

The boy that cried wolf. If the guages read wrong how do you know when they are right and the temps really are in dangerous levels? Doesn't that seem like a problem to be recalled?
 

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We got confirmation from ford 2 years ago that the oil temp and pressure gauges were for show only.

I monitor the water temp and will short shift if it starts to right of middle.

I guess I could get real sensors, but then again replacement motors are cheap and it's still running strong after 68k miles. I'd say a good 4k of those were above 6k rpm.

You should be more concerned about power steering failure or an axle nut coming loose.
 

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It is a mechanical valve controlled by temperature to adjust the flow of water to the radiator. There is nothing to read.

Temperature is a measure of heat and what mechanical device is interpereting that incrimental change of heat to make a valve open or close. Something has to tell a valve to open or close. Is the ECU telling the valve to open? Where is the ECU getting its information to tell the vavle to open?
This is not an insult, but you know just enough to be dangerous. Yes temp is a measure of heat, per say. Wait let me ask you this what makes a thermometer in your mouth move from the low number to the high numbers? Heat. Heat is what opens the valve to the radiator. Nothing else.
 

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If the fancy idiot lights work improperly then how do I know if the engine is going to overheat?
You do not. Just like a car without the gauges.

Do the engine temp sensors go bad or need calibration? Mine will read pegged out max before the fans kick on. I freaked out thinking it was going to overheat and cause damage.
They can go bad, they cannot be calibrated. Again they are just fancy idiot lights.

The boy that cried wolf. If the guages read wrong how do you know when they are right and the temps really are in dangerous levels? Doesn't that seem like a problem to be recalled?
Again you don't. If you have low oil pressure an idiot light will light up. I think there is a light for over heating too, but I can't remember off the top of my head.
 
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