Good post. On the same note, I don't think Ford has made one accurate oil pressure guage, ever.

 

Our 47' Mercury has a pretty damn accurate gauge on it! :dunno2:

 

+1 my wife always gets pissed when we take my car, and she has to wait for it to warm up. always bustin balls....

 

That is ridiculous. Any car can be driven from a dead cold temp, just do not beat on the car until it is at operating temp.

Actually the best way to warm a car up is to just hop in and drive it, then the entire driveline gets up to operating temp, not just the engine.

--Joe

 

The sender is a 6 PSI pressure switch. The stock gauge is an idiot light in the form of a gauge. Ford has been doing this since the early 90s. Apparently it cuts down on unneccessary warranty service due to retarded owners.

 

Same is true with the coolant temp gauge. It doesn't move much. The car has to get really hot to put it in red.

 

yup dummy light for sure. I had to change 2 of the senders on my 94 5.0 as it was bouncing all over the place.. later i was like **** this installed a manual gauge to check it.. sure as shit at warm idle i was under 6psi oil pressure. The years of boost and nitrous had taken its toll on the main bearings .. 1 of them was so bad i could see thru it lol

 

I am designing a set of gauge upgrade circuits that will allow Mustang owners to upgrade thier temperature gauges to read accurately so I have researched this topic pretty deeply on clusters from 94-04 Mustangs.

Up through 98, the gauges are d'Arsonval movements, (except for the speedometer and tachometer). The volt gauges are voltmeters and the rest of the minor gauges are ammeters. From 99-04, the clusters are controlled by a microprocessor and the gauges are air-core movements. From 05 up the gauge movements are all little stepper motors.

From the early 90s, Ford went to the 6 PSI switch for its oil pressure sender, adding a 20 ohm resistor in series to keep the needle in the high-normal range when the switch is closed. In the clusters of the 97-98 cars, they changed the oil pressure gauge to have more internal impedance so they could eliminate the 20 ohm resistor on the back of the cluster. When they went to the microprocessor controlled cluster starting in 99, they did the equivalent of the resistor in the cluster controller software.

Prior to 99 the temp gauges are actually pretty accurate and consistent, especially at the hot mark. They are just not marked with any temperature numbers. From 99 to 04, the PCM reads the temperature from its sender, and then sends the temp data to the cluster via the CAN bus. I do not have a 99-04 car, so I was unable to test the accuracy of the 99-04 temp gauge software in the cluster processor, but based on Eric's experience and Ford's practice with the other gauges, their software "dumbed down" the temperature gauges too.

Regarding the volt gauges, from 94-98, the 8V mark is very accurate, but at 18V, the needle will point just a touch under the 18V mark. From 99-04, here is the data for the volt gauge:

15V: reads a touch over mid-gauge
14V: reads a touch over mid-gauge
13V: reads a touch over mid-gauge
12V: reads a touch over mid-gauge
11V: reads at about 33% of the normal range
10V: reads at Low-Normal mark
9V: reads at the L mark
8V: reads a little below the L mark

I am designing 3 PIC processor-based circuits that will allow 94-04 Mustang owners to upgrade thier clusters to make them accurate. One circuit will be for 94-96 cars, one for 97-98 and the third and last for 99-04 cars. It drives me nuts that the stock gauges are in exactly the right place, but they don't work worth a damn. I am also working with an aftermarket gauge face maker to get stock looking gauge faces with stock looking oil pressure, temp and voltage numbers on them.

Here is what the 99-04 GT gauge gace will look like, FYI (courtesy of Scott at www.customgaugefaces.com):

Here is what it looks like in the cluster:

My documentation of this work was noticed by some Ford engineers who are now on the list to buy these upgrades. They started an internal email debate about Ford's retarded gauge philosophy, but unfortunately, they lost. So Ford gauges will contunue to be retarded.

If I were Ford, since the instrument clusters are microprocessor based, I would add an expensive option to the options list to order a car with a properly calibrated instrument cluster. But they don't listen to me...

 

very nice-keep us informed

 

Dude that's badass. I'd love a setup for my 03 Cobra when available!

 

Damn Mark. I'm glad we got dudes like you in the Mustang world.

 

Wow Mark. I'm impressed.

 

I'm in for a set if they come available. Good info, and great work Mark!

 

They will become available. It is just a matter of time. I am getting really close to having a prototype of the first circuit that I can install in my 96 Cobra for reliability testing. I am designing the circuits to go under the hood for the 94-96 and 97-98 units for easy installation. The 99-04 units will go behind the dash, and the sender wires will need to run through the firewall. I have been significantly delayed with my 99-04 design work due to the lack of availability of logic-level P-channel MOSFET transistors, believe it or not. The transistors are due to come in sometime this quarter, so I can restart the design work for that circuit then.

So it will happen, but it is hard to say exactly when.

 

Since you all are interested, if you want to read the background on the whole project, I am documenting it here: http://www.classictiger.com/mustang/OilPressureGauge/OilPressureGauge.htm

Any advice or input is appreciated.

Mark

 

i'd like see your SVT cobra white face gauges offered with a blue glow instead of the green. i think the blue would look absolutely sick.

 

To get around the useless Ford guages I have duplicated just about every gauge with an Autometer guage. Which I really would have preferred not doing, since all those guages look so ricey.

I will be looking forward to your solution for inaccurate guages in the 03 Cobra. Consider me a bought and sold customer.

 

I'm in for a set if they come available too!!

 

Very nice project and posts and updates.

Looking forward to the results and finished project.

 

I'd be another anxious buying waiting for these. It would also be nice to see 200mph speed-o-meters and 9000 rpm tachs.

 

Mark, looks like you've sold a bunch of these things already, and haven't even finished them yet!

 

i would def be on the buyers list as well

from what i have read however the 03/04 cobra cluster isn't at all interchangeable with the other 99-04 mustang clusters however (?) something to do with the pcm and the fact that there is no voltmeter

 

This is a mod for your existing cluster. The way the system will work in the 99-04 clusters is you will pull the circuit board off the back of the cluster, open the oil pressure and temp gauge pin holes in the PCB up a tiny bit, run a wire with an insulated connector through each hole and plug it to the gauge pin. You will then slide the PCB back down over those wires and connectors and plug the PCB back in to the cluster. This will keep all of the other cluster features working while isolating those two gauges from the cluster. The wires you plugged onto the gauge pins will then go to my upgrade module which will also need hot-in-start-and-run power and ground. You will run sensor wires to the oil pressure sender where you will install an Autometer oil pressure sender and to wherever you want to install the Ford temperature sender. If you want a low oil pressure light, there will be an output you can use to drive an LED. Some people will just replace the seat belt light bulb with this LED, but I am planning on using the OD Off indicator on my cluster since I have a manual transmission.

You can run this with the stock gauge faces but I think the real value will be if you replace the gauge faces with stock looking custom ones with numbers. I'll also be replacing my OD Off indicator with an oil can icon when I have the custom gauge face made. It is really easy to replace gauge faces and calibrate the needles in 99-04 clusters, except for the mechanical boost gauges in the Cobras. Needle calibration with these clusters can be done with a 9V battery and 4 clip leads. The needle calibration for the mechanical boost gauges will have to be done the same way it is done when you install a boost gauge overlay.

I still have to finish the design, but assuming I can get the assembly house to manufacture these things for what I think they will do it, I'll be able to sell them for a little under $300 and still make a few bucks. You'll have to add the cost of the gauge faces, oil pressure sender and temp sender, each of which will be under $50. No labor if you do it yourself.

It will proabably be late summer before this design work is done. It is actually a very complex system design.

If you guys want to help, I would appreciate suggestions for where you want to mount your temp sender and what size the sender hole is so I can do the right thing for you all. While I don't have a Terminator, I am building a Teksid Terminator motor for my 96 so I do have an 03 Cobra motor to play with on my engine stand. (The head porting work is taking a back seat to the electrical engineering work, which is too bad.)

 

I forgot to mention that I am designing it so you can easily take the custer back to stock, too, should you ever want to.

 

Another customer here when you are ready!!

 

Long as you make the gauges exact I'd be down for that. If anything give it extra numbers at the bottom for the speed. 180 will do fine for me before it bottoms out.

 

In 99-04 cars, the speedometer signal comes from the OSS sensor on the tailshaft (used to be VSS in the older cars) and goes only to the PCM. The PCM then calculates the actual speed from that signal and sends it to the cluster microprocessor via the CAN bus. I have no way of testing a 99-04 cluster to see what the speedo does over the top speed on the speedometer. If the needle keeps going, and you want a higher top speed on the face, someone will need to get their car on a dyno and take a picture of where the needle is at the speeds higher than the top mark on the stock cluster. From those pictures, Scott can make a custom speedometer that reads higher for you.

Sorry I can't do this on the bench for 99-04 cars.

I will try it on the bench for the 94-98 cars, though, to see what happens.

 

Mark, is there any way to recalibrate the speedometer and put, say, 200MPH at the 160 position and move the rest of the numbers around?

 

There must be a way to do it, but I don't know how. It has to be in the software that runs on the cluster controller, although there is an outside chance that it is in the PCM software or both. I know it can be done, because Roush has 200MPH clusters. A guy who had put a Roush 200MPH gauge face on a Cobra 160MPH cluster was asking me if I could help him make it work. Unfortunately, the only way I can see that Roush could have done it was to either reprogram the cluster and/or PCM or get Ford to do it for them.

I could design a similar circuit to the one that I am designing for the 99-04 oil pressure and temp guage to drive the speedometer from the OSS signal, but that would probably cost another $300 for the speedometer circuit alone.

FYI, Ford could easily do what I am doing by simply reprogramming thier clusters.

BTW, I also don't know how to do that with a 94-98 speedometer either, because those speedos are made with custom ICs that I can't figure out.

 

Mark, when you get everything done with these clusters please please make an announcement and have more then a hand full around. I am eagerly waiting for one.

 

Have you thought about asking roush or ford if they can tell you how to do it? Sometimes they are stingy and sometimes they just let stuff go.

 

I will try this. It certainly would make things easier.