'94-'04 Mustang Clusters
1994-2004 Mustang & Other Ford Instrument Clusters
Mark had a 1996 Mustang Cobra. He started studying the cluster in his car and then expanded it to '94-'04 clusters and beyond. From that base, he developed services, products and lots of good information for Mustang owners. Much of this also applies to other Ford vehicles of this era, especially F150 trucks.
Crank Position Sensor Trigger Wheel
Since the engine you are swapping into your Ford will probably have its own trigger wheel, you can probably use the new engine's crank position sensor signal to drive the stock PCM and get the tachometer to work. But the new engine has to have a trigger wheel with the same number of teeth as your original engine. It also has to use the same reluctor type of crank position sensor. If it uses a Hall effect type sensor, you will need to use something like a Dakota Digital SGI-100BT speedometer adapter to convert the signal from Hall effect style to reluctor style.
I have done some research and have learned that all of Ford's 4.6, 5.4 and the new 5.0 Coyote engines use a 36-1 trigger wheel and a reluctor style sensor:
36-1 Trigger Wheel
To get the tachometer to work in a 99-04 Mustang with a 5.0 Coyote swap, all you need to do is splice the stock 99-04 PCM's Dark Blue Crank Position Sensor wire to the Coyote motor's Yellow/Purple Crank Position Sensor signal wire. Do not splice the 00-04 PCM's Gray CPS return wire to the Coyote motor's Green/Brown return wire. If you need to extent the wire to get to the splice, I strongly recommend you salvage a length of Ford Crank position sensor wire for the splice from a junkyard car or your 99-04 engine harness. It is a shielded wire and may be twisted pair for EMI noise immunity. If you get ElectroMagnetic Interference (EMI) on that signal, it could play havoc with its operation. Be sure to also splice the shielded extension wire shield to the shield on the 99-04 wire as well, but not to the Coyote harness side. I would recommend that you make the splice at the sensor connector if you are putting the Coyote PCM near the front of the engine, at the engine harness connector if you are putting the Coyote PCM near the rear of the engine or at the stock PCM harness connector if you are putting the Coyote PCM in the interior of the vehicle.
Joel at Warrior Racing has done this swap and has confirmed that it does work. He also confirmed that connecting the 99-04 return signal to the Coyote PCM's return signal will cause it to not work. He added a 100 Ohm resistor between the splice and the 99-04 CPS wire to better isolate the 99-04 electrical load on the Coyote signal. He also told me that this mod is required in order to get the AC to work with this swap. Many thanks to Joel for confirming this.
Swerve on Modfords has installed a Holley Dominator into his Mustang. He left his stock AMZ2 Ford ECU in place to drive the gauges. He used the Holley Hall effect CPS sensor driven by a 12V reference signal. He was able to make the stock tachometer work by coupling the Hall effect sensor signal to the stock ECU through a 4.7uF, 25V capacitor. Make sure you put the negative side of the cap towards the stock ECU.
If you are doing other swaps, such as a Chevy LS motor (yes, people do this swap), you will need to get a bit more creative. Chevy LS motors use a reluctor style sensor for their Crank Position Sensors, so you do not have to worry about converting from a Hall effect signal to a reluctor style signal. (FYI, the Chevy LS cam position sensor are Hall effect sensors. Go figure.) Chevy LS motors up to sometime in 2006 used a 24 tooth trigger wheel, but late 2006 and up LS motors use a 58 tooth trigger wheel.
You will need to use a recalibrator to scale the LS Crank Position Sensor signal frequency to the frequency that the 99-4 Ford PCM expects. Since the signals in both systems are reluctor style, a speedometer recalibrator does not need to be used. I recommend that the FRPP Recalibrator be used in this application. It is not clear if the recalibrator you use will pass the missing tooth information through to the PCM. I don't know if the PCM needs the missing tooth signal to work. This could be a reason this will not work for this swap.
If you are willing to experiment, connect the input to the FRPP Recalibrator to the LS Crank Position sensor signal and connect the output of the recalibrator to the Crank Position Sensor signal input to the 99-04 PCM. You should also use shielded wire, especially between the sensor and the Recalibrator.
Craig Kelsey reports that he has had good luck with using laser-cut reluctor wheels from www.trigger-wheels.com. They are based in the UK, but will ship all over the world.
CAVEAT: Ford does a really good job of protecting the inputs to its PCMs. This connection is very unlikely to damage your 99-04 Ford PCM. But until someone verifies that this will work, you do this at your own risk.
As an aside, Jayem also cut 6 slots in the Toyota output shaft and mounted the stock OSS sensor on a fabricated bracket near the output shaft, and his speedometer also worked correctly:
DIY Output Shaft Sensor
Swap in an older cluster: One way I can think of that will allow you to have a working tachometer in a 99-04 Mustang is if you swap in an older 94-98 Mustang cluster. You will need a set of connector pigtails for the swapped cluster as well. You will need the coolant temperature gauge sensor and connector from the same year car as the cluster as well.
The tachometer output from the new PCM should be able to drive the older tachometer. If the PCM does not have a tach output signal, you can use a tach adapter from a company such as Autometer. If you are swapping from V8 to V6 or vice versa, be sure to ground or unground the cylinder select signal and recalibrate the tach as described here.
The speedometer may need a speedometer recalibrator such as the Dakota Digital SGI-100BT to scale the new drivetrain's speed signal to the 8000 pulse per mile signal the old cluster expects. If the new drive train has a Hall effect style speed sensor, be sure to set the Dakota Digital SGI-100BT to convert the digital speed signal to an analog speed signal out to the car's electronics.
The fuel gauge and fuel level sensor are close enough that there will be no problem with them.
The oil pressure gauge works from a 6PSI pressure switch which most new drivetrains also has, so it should work. However, if you want to upgrade your oil pressure gauge to be a real gauge, you can use the MeterMatch upgrade .
The volt gauge reads the power to the cluster, so no change is require for it to function properly.
The PATS system for your new drivetrain will not work. I recommend you install a hidden kill switch.
I am not sure if the charge indicator lamp will work, but it should.
If the new drivetrain PCM has a CEL output, it should work with the older cluster.
The newer drivetrain will probably not have a low oil level sensor, so that will probably not work.
The ABS light should work the same.
The turn signal and high beam indicators should work the same.
The cluster illumination should also work the same.
The 99-04 cars do not have the brake indicator lamp that the older cars do, to the brake indicator will not work unless you add the wiring per a 94-98 car.
Since I have not actually done this type of swap, I may have made an error or two. All of this was worked out with the EVTMs. If you do this swap and find there are errors or misleading information here, please contact us to let us know how to fix this page.
1994-98 Mustang Tachometer Reverse Engineering
I have reverse engineered the tachometer from a 94-95 Ford Mustang. Ford may have made small revisions later in production, but the differences should not be significant. You should double check component values prior to working on your tachometer. It was impossible to read the components numbers for capacitors C2 and C3 without removing them from the PCB, so I guessed which is which. The R7 trimpot value is unknown without taking it out of the circuit. It measures about 70K ohms in circuit.
The heart of the tachometer is a CS8190 Precision Air-Core Tach/Speedo Driver with Return to Zero integrated circuit. Here are the tachometer schematics:
