Gauges....To Trust or Not To Trust

[Goose428]

Hello Everyone,

I took my 08' Bullitt to Big Willow last month, and had an enjoyable experience.

One question I had, and nobody seems to know exactly, is how accurate the gauges are.

Specifically, the coolant temperature gauge. How accurate is it? If my car is at operating temp, the gauge is ALWAYS at the 12'o clock position, no matter if i'm slowly cruising on the freeway on a 50 degree day, or on my 5th lap of Willow Springs on an 85 Degree day.

If I see it move past the 12 o'clock position, does that mean it's too late? Same goes for the oil pressure gauge. It never moves with the RPM of the engine, so I can't imagine it is that accurate.

Also, if the coolant temperature gauge or oil pressure gauge move to a "non-normal" amount, will the car give me an audible alarm? Given how small and unresponsive the gauges are, it seems like it could be pretty easy to continue to drive the car even if one of the gauges are in the "danger" zone.....

Sorry if this has been asked before, I did a search and didn't find anything concrete.

Thank You

 

[skwerl]

Ford hasn't put a working oil pressure gauge in any vehicle for the last 40 years. It's simply a dial and needle hooked up to an on/off sensor. Either you have pressure or you don't.

Plenty of aftermarket gauges available, many can simply plug into your OBDII port and display all sorts of info. The data is already there in the computer but Ford doesn't trust operators with real gauges.

 

[Wes06]

True. Get an aftermarket oil pressure sensor. And either add a coolant sensor, or use one that reads obd2 data that can get coolant.
Side note oem coolant temp is inferred off head temps.

 

[Juice]

IMO, the temp guage works and can be relied on. The 12 'oclock position is about 195*F, and I verified this with OBD data.

I can't comment on the oil pressure, as I have a 4 guage cluster, so I'm running aftermarket oil press&temp guages.

Don't know about audible warnings. But I can tell from experience that you NEED to train yourself to check the guages regularly at track days.

 

[Pentalab]

The aeroforce gauges that plug into the OBD port can also be programmed to emit either an audible or visual, (or both) alarm if a given parameter threshold is exceeded. You can alarm anything you want, like cyl head temp, coolant, oil temp, oil pressure etc, etc.
The coolant temp is derived from the cyl head temps.

When cruising, my temp gauge is just below the halfway mark on my 2010. 2 weeks ago, I lost both my low + high speed eng fan. Didn't notice as I was in rush hour traffic, barely
crawling along. What got my attention asap, was the entire ford temp coolant gauge lit up RED ! I then saw the coolant gauge 3/4 scale. Switched the aeroforce gauges to read both cyl head temps and also coolant temps.

Aeroforce gauges indicated the cyl head temps were 253 F..and the coolant was 238 F.
Temp 'fix' was to crank up the heat to max inside the car, heater blower on max, and both windows down. That brought it down a bit, and the ford temp gauge was no longer in the red after a while. Then babied it home. Since fixed the eng fan issue.

The overheating took place after dark. If that was during the day, I doubt I would have noticed the ford temp gauge pod lighting up RED. And no, I didn't have the aeroforce gauges set up for alarm mode for eng coolant thresholds. Live + learn.

 

[Jay.GT]

Just thought I'd add in a little bit, the obd2 readings won't display oil pressure or temp. At least that's how my sct x4 is for my 06. I know they made some changes to the 07+ models, that could be one of them. Not in the 06 though.

Just didn't want you getting one of these expensive ass readers with unfufilled expectations.

 

[Pentalab]

Just thought I'd add in a little bit, the obd2 readings won't display oil pressure or temp. At least that's how my sct x4 is for my 06. I know they made some changes to the 07+ models, that could be one of them. Not in the 06 though.

Just didn't want you getting one of these expensive ass readers with unfufilled expectations.

Correct. With any of the aeroforce gauges, or anything else, like my SCT X3, or X4 etc, to read aux stuff like oil pressure or oil temp, requires the use of outboard oil pressure and oil temp sensors, that are then fed to the aeroforce aux 1 and aux 2 inputs. Still, with those outboard sensors included in the mix, they too can be alarmed if you want.

The aeroforce gauges only have 2 aux inputs per gauge. I have 3 x aeroforce gauges mounted to the A pillar, so a total of 6 x aux inputs can be used, if required. 1-2 aeroforce gauges is ample for most applications. Other uses for the aux inputs are stuff like AFR sensors. Some folks will install one on drivers side, or pass side, or both sides. The 11+ cars have wideband front O2 sensors that already read afr.

 

[stevbd]

If the "coolant temp" is actually derived from the cylinder head temp, and seems to work, can we safely assume oil temp also is related to the coolant temp gauge? Should I care what the oil temp is, if the cylinder head is not overheated? Or put differently, has anyone with separate gauges seen dangerously high oil temps without the factory coolant (cylinder head) temp gauge moving?

 

[Juice]

If the "coolant temp" is actually derived from the cylinder head temp, and seems to work, can we safely assume oil temp also is related to the coolant temp gauge? Should I care what the oil temp is, if the cylinder head is not overheated? Or put differently, has anyone with separate gauges seen dangerously high oil temps without the factory coolant (cylinder head) temp gauge moving?

What would you consider "dangerously high oil temp"? And yes, I've seen "higher than usual" oil temps on track. Normally, on the street, I see 185*F oil temp in the summer. Now, in the cold, oil temp stays below 140*. On an open track, 85*F ambient temp, I've seen 250*F with water temp guage at 12 'oclock/normal.

So that is over 100*F oil temp difference all with the water temp at 12 'oclock.

 

[Pentalab]

Some of the track folks on corner carvers, without oil coolers, have seen a bit > 300 deg F. Dino oil is basically done at 250 F. Synthetic is pretty much maxed out by 300 F.

 

[RED09GT]

Ford hasn't put a working oil pressure gauge in any vehicle for the last 40 years. It's simply a dial and needle hooked up to an on/off sensor. Either you have pressure or you don't.

The only exception that I have seen is the SVT focus. Mine does react to RPM and also changes range depending on what the oil temperature gauge is doing.

 

[702GT]

The only reason you'd really have to worry about oil temp is if you were a road course racing or auto x, and just about all of the professional racing genre. Street car, doesn't need oil temp (unless you tow with your street baby.... maybe). Some would argue turbo applications may need them, personally I think turbo guys should be more worried about EGT's than oil temp, as EGT will tell you a lot more about what's going on with your turbo and engine than oil temp will. But if you're big on the cockpit view, it's just another port and sensor.

I'm a fan of the big 3. Oil Pressure, Coolant Temp, and Wideband. These 3 will give you the most heads up for oncoming problems than virtually any other data sensor. They are also the most diagnostically valuable.

The OEM temp gauges is dogshit/trash/waste of viewing time. Don't even look at it, it's wrong. What is "normal." And don't tell me 194 degrees. That's the temperature at which the gauge "reads normal." I have datalogs of a friends '07 Roush 427R from when he used to auto x with it. His coolant temps would be as high as 138 degrees and the OEM temp gauges reads "normal." So piss off with "normal." You need to know when your motors coolant temp is on the move. If it's steadily climbing from 195 to 200 to 210 to 220, you need to be ready to cool it down or prepare to shut down the motor and pray. A motor should only operate in extreme conditions for short durations, and only when necessary. I've seen some high coolant temps from trucks pulling loads through the hills/mountains, but the majority of truck cooling systems are *designed* to handle extreme conditions, and there's maintenance procedures for those conditions. So again, piss off with "normal." If it's "normal," then you don't really know what your engines coolant temp is other than it's within the range of 195-240+ degrees.

Oil pressure is also vital. 99% of the time, the gauge is just a neat decorative feature. But, should you ever have engines issues (funky idle, surging, ticking, clicking, clacking, knocking, thunking, and any other sound/vibration/abnormality) the oil pressure gauge suddenly becomes a vital diagnostic tool to help eliminate, prove/disprove issues. It's also a great early warning indication of wear/tear on bearings/seals/tolerances. If you start out at 30k/mi and a hot idle of 25psi and at 100k/mi you have a hot idle of 20psi, it may be time to move up to a 5w30 oil or prepare for a rebuild. These aren't specific figures, just saying for example the benefits of a real oil pressure gauge.

And the wideband should need no explanation of its benefits. Everything above and beyond the big 3 is, well, above and beyond. I didn't mention a fuel pressure gauge, the OE fuel system is returnless and is usually fairly static. A wideband will tell you more than a fuel pressure gauge will with most fueling issues. A small gauge under the hood at the fuel rail would be my choice if I were to ever use a fuel pressure gauge in a returnless setup. If going return, I would certainly want a fuel pressure gauge in the cabin, however.

Just my $0.02

 

[Pentalab]

The fuel rail pressure ( typ 40 psi) and also fuel temp, can already be read off the OBD port.
The oem oil pressure gauge on the dash is useless, it doens't budge. The 'coolant' temp as read off the obd port (or the oem dash gauge) is derived from an algorithm based on cyl head temps, which is an actual bona fide sensor.

However, the low and high speed fan threshold setting are indeed based on the ..'coolant' temps as indicated on the obd port. IF you have the beginnings of a clogged cat, you will see that cat's temp rise, which is why I don't like the idea of shutting off the rear o2 sensors in the tune.

Oil pressure gauge is a huge bonus. If AutoX racer had a oil pressure gauge on his 08 roush, he would have seen that his eng was going south on him, way before it started to bite the dust. dealer looks at it, sez the oil pressure is way too low, they take eng apart, it's trashed. After his rebuild, in went the oil pressure and temp gauges, and also a wideband afr...in both banks. These are all data points, and when you start having any type of various issues, you now have data at your finger tips.

If you really want to go crazy, you can also install a coolant gauge sensor for the IC-HE- pump loop. Lose the IC pump, and IC coolant temps skyrocket...ditto with IAT's.

Any of the above can easily be alarmed on the aeroforce gauges..for whatever threshold you desire. You can also use em to do stuff like turn on aux fans for a HE if required.. via a spare 40A SPST relay. You can also do combo alarms with the aeroforce gauges.... like IF the rpm > 5000 rpm, AND the oil pressure is below XXX psi, bring in an alarm.

I would have never known I had an automatic tranny fluid overheating problem (with blower on for just 4-6 secs) with out seeing it on the obd port / aeroforce gauges. So in went the 2nd auto tranny cooler, in series with the oem unit...problem solved.

Usual deal is when somebody loses an eng, in goes every aux sensor you can think of. They want to see problems, potential issues, trends etc, before things get out of hand. With all the sensors in place, then you can note it all down, as to what is normal. Then when items start to deviate from normal, you can be on top of it asap.

A few folks have lost engs due to clogged cats. Roush had lousy tunes back in early 2012, way too rich, some had a cat clog, then take out the eng. IF you could have seen both cat temps and also the afr on both banks, you would know what the issue was asap.

 

[AndrewNagle]

Oil pressure gauge is a huge bonus. If AutoX racer had a oil pressure gauge on his 08 roush, he would have seen that his eng was going south on him, way before it started to bite the dust. dealer looks at it, sez the oil pressure is way too low, they take eng apart, it's trashed. After his rebuild, in went the oil pressure and temp gauges, and also a wideband afr...in both banks. These are all data points, and when you start having any type of various issues, you now have data at your finger tips.

Saved my engine.

 

[white08gt]

check out SpeedHut.com for your gauges, this is what I run for the last 8 years. I went for the Legacy mid grade, you choose your font, color both for gauges and back lite for no extra charge. pretty neat to do this and can even put your name with a minimal charge. cost less than Auto Meter and other big names with a life time warranty made in USA.

 

[AndrewNagle]

check out SpeedHut.com for your gauges, this is what I run for the last 8 years. I went for the Legacy mid grade, you choose your font, color both for gauges and back lite for no extra charge. pretty neat to do this and can even put your name with a minimal charge. cost less than Auto Meter and other big names with a life time warranty made in USA.

Thanks for sharing, very cool. Too back all my gauge are already AutoMeter Cobalts

 

[RocketcarX]

I think gauges are a waste of time left over from the days of analog junk for OEM gauges.
Think of it like this, these sensor are good enough to run and tune your vehicle by, the ECU sees number not approximations, these numbers are accurate, hence some recommendations for the NGauge OBD2 gauge which simply displays the numbers from the same sensors you factory gauges use.
I added a wide band to my car for tuning, I have found the Sport Comp II gauges from Autometer match our factory gauges almost perfectly if you're into continuity.

 

[Pentalab]

I think gauges are a waste of time left over from the days of analog junk for OEM gauges.
Think of it like this, these sensor are good enough to run and tune your vehicle by, the ECU sees number not approximations, these numbers are accurate, hence some recommendations for the NGauge OBD2 gauge which simply displays the numbers from the same sensors you factory gauges use.
I added a wide band to my car for tuning, I have found the Sport Comp II gauges from Autometer match our factory gauges almost perfectly if you're into continuity.

I used 3 x aeroforce digital readout gauges, and all 3 plugged into the obd port. 2 of em are cabled into one plug. Y cable combines the plug from the 1st pair, with the plug from gauge #3. Output of Y feeds the OBD port. Roush boost gauge goes into the air vent to the left of the steering wheel, so all 4 gauges are in a row. 3 x aeroforce gauges mounted on a SOS A pillar. With 6 x aux inputs on the digital gauges, then stuff like wideband(S), oil pressure, oil temp, IC coolant temps, and anything else you want, can easily be added.

When you have an issue with anything, you know asap. Analog individual gauges will only indicate one parameter. The aeroforce and no doubt other digital gauges will read 32 x parameters on my 2010.
(30 + 2 aux inputs on each aeroforce).

Just don't get too wrapped up in reading a myriad of gauges, while blasting along at speed.

 

[RocketcarX]

I used 3 x aeroforce digital readout gauges, and all 3 plugged into the obd port. 2 of em are cabled into one plug. Y cable combines the plug from the 1st pair, with the plug from gauge #3. Output of Y feeds the OBD port. Roush boost gauge goes into the air vent to the left of the steering wheel, so all 4 gauges are in a row. 3 x aeroforce gauges mounted on a SOS A pillar. With 6 x aux inputs on the digital gauges, then stuff like wideband(S), oil pressure, oil temp, IC coolant temps, and anything else you want, can easily be added.

When you have an issue with anything, you know asap. Analog individual gauges will only indicate one parameter. The aeroforce and no doubt other digital gauges will read 32 x parameters on my 2010.
(30 + 2 aux inputs on each aeroforce).

Just don't get too wrapped up in reading a myriad of gauges, while blasting along at speed.

The engine light will come on when things are a problem as well as the gauges in certain year models actually changing the LED backlight color to red when the are reading a problem. I will concede these gauges could help indicate trends or help spot a problem coming, maybe. To be honest most of the time (unless its just coolant temp) by the time your oil pressure or oil temp indicates a problem you're fucked. Unless you're regularly logging gauge readings you'll be hard pressed to use them for anything other than to verify a failure as its happening or for the same peace of mind you can get by simply scanning the gauges already in front of you.

 

[o2sys]

I only have aftermarket gauges for sensors that my 07 didn't come with. Wideband and Boost. I do use the torque app with the obd2 Bluetooth adapter to monitor other stuff as well though.


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