How To Install A Holley Terminator X EFI System On A Coyote-Swapped Fox Body Mustang

10 min read

How To Install A Holley Terminator X EFI System On A Coyote-Swapped Fox Body Mustang

10 min read

Since the very beginning days of hot-rodding, car owners have been doing whatever they could think of to improve the performance of their cars. Back then the most common approach was to simply locate a bigger, more powerful engine to swap into the car. Swapping in a Cadillac V-8 for a flathead Ford was a relatively easy way to get your Model A down the track a whole lot quicker. Back then, the swap was pure mechanical. Just figure out how to get everything bolted together and you were good to go. Eventually, the car companies figured out that there was a market for high performance cars and the time period most often referred to as the "muscle car era" was born. If your car wasn’t fast enough, you could buy a faster one or just get a larger engine, modify it to your preference and likely simply bolt it in place.

Jumping ahead to today, there is more factory HP available than any of us could have ever dreamed possible during the original muscle car days. Walk into a dealership and drive away with 700+ emissions legal HP under your right foot? No way, not possible! And get decent cruising mileage too? Forget it, it can't be done. Well it happened, it is happening and it’s still getting better.

While all of this amazing engine technology has been awesome in new cars, it initially took the oldest hot rodding trick off the table for a time. Exchanging the smaller engine for a bigger one became a bit more of a problem when computers didn't appreciate engine modifications...and that was if you were able to use the computer at all. In many cases, you needed pretty much everything that came with the donor vehicle for the new engine to work. Aftermarket engine management systems eventually allowed competent programmers to perform near-miracles and bring true hot rodding back to life again, but for some of us the learning curve was just more than we were comfortable with.

Coyote Fox TermX Fuel Pump

Older cars will of course need an electric fuel pump installed that will flow a minimum of 255 lbs/hr at 58 PSI. Note that volume and pressure specs are engine specific.

Then Holley introduced the Sniper and more recently, the Terminator X and the Terminator X Max. Both are self-learning systems that can be fully set up without the need for an external computer. (Though if you are enough of a geek to enjoy that sort of thing, you can plug in your laptop and tweak with the settings all you’d like.)

Muscle Car Restorations of Chippewa Falls, Wisconsin has installed both systems in vehicles and both times the initial start up only involved one turn of the key, with the engine quickly settling into a normal idle. Upon reaching operating temp, a few parameters were checked and maybe adjusted a bit, and then the car was pretty much ready to drive in learning mode.

Using the phrase “plug and play” might seem a bit simplistic for any EFI system, especially for a standalone engine system for a modern engine like the Ford Coyote, but Holley has essentially done just that...just make no mistake, you will have to read the instruction manual.

Terminator Coyote Fox Body Terminator System

These are the basic components. From the left we have the Ti-VCT (variable cam timing) controller, the hand held controller, a pair of coil drivers (one for each bank) and the Terminator ECU.

MCR had recently installed a new Coyote into an 1988 Mustang and we were invited out to observe the initial system mockup before the final paint and assembly was done. After that, we got to witness the final setup and initial dyno runs.

Since this Coyote will be run drive-by-wire, the Terminator X Max version was used. Both Terminator versions include variable cam timing control via pre-loaded tables. Base MAP tables are pre-loaded, in this case specifically for the Gen 2 Coyote. The transmission control functionality will not be used in this car as it is running a manual trans.

Once the installation was complete, the entirety of the set up was done on the small hand-held controller, with no laptop needed. The setup wizard took us through the input of the various engine parameters and options. A number of options are available for adjusting timing, idle air control (IAC) settings, startup fuel enrichment settings, and so on, but we left them all as-is for the initial fire up.

TerminatorX Coyote Mustang dip switch panel

On the back of the VCT is a dip switch panel that will need to be set for the particular application. In this case, a GEN 2 Coyote.

The engine came to life on the first key twist and after a brief warm up it was driven from MCR’s assembly building to their Mustang Chassis Dyno for simulated driving time and tests. It literally couldn’t have been any smoother.

Once the Mustang was strapped down on the dyno, MCR followed Holley’s process to help the system self-tune. That starts with holding the engine at different RPMs in neutral at speeds up to about 2500 RPM. This starts the learning process. After that, MCR then did some easy driving on the dyno moving the engine through various load and RPM conditions. Everything worked flawlessly so they continued to add power and RPMs until it seemed time to do some full power dyno pulls.

Expecting to see power gains with each successive full power run, everyone was surprised when that didn’t happen. Instead, the system apparently learned enough through the driving sequence to get it right the first time. Five pulls in a row produced essentially the same power level of 371 HP and 340 lb-ft of torque at the rear wheels. The Terminator X learns fast, real fast.

If you’ve been considering a late model engine swap into your favorite ride but have been a bit intimidated by the complexity of the setup and tuning of a full featured standalone engine management system then do yourself a favor and take a good look at Holley’s Terminator X system. You’ll be up and running and cruising faster than you think.

TerminatorX Coyote Fox Body mock-up

Muscle Car Restorations always performs a complete mock up of the entire system before final paint and assembly so the optimum location for the control boxes can be determined.

TerminatorX Coyote Fox Body coil plugs

The coil plugs are all clearly marked, making their installation a literal snap.

TerminatorX Coyote Fox Body TPS and IAC

All of the other connectors are similarly marked. These are for the TPS and IAC. However these won’t be used for this application as this will be a drive-by-wire system.

TerminatorX Coyote Fox Body special instructions

Special instructions are also included where needed. The coil ground wires must be bolted directly to the cylinder head.

TerminatorX Coyote Fox Body wiring under manifold

As part of the mock up process, MCR removed the intake manifold as there was room under it to hide some of the wiring harness.

TerminatorX Coyote Fox Body ECU and Ti-VCT

The ECU and Ti-VCT controller can be mounted under dash or under hood. MCR found a great spot on the inner fender in front of the shock tower to mount these away from excess heat and noisy electronics.

TerminatorX Coyote Fox Body coil drivers and roll control

The pair of coil drivers also found a home on the inner fender, under a Hurst roll control valve.

TerminatorX Coyote Fox Body complete mock-up

Once the mock up is complete, things look a lot neater. The Terminator X manages all the factory engine functions but can also handle nitrous, turbos and blower systems if you are so inclined.

TerminatorX Coyote Fox Body Controller Wizard 1

The system setup starts with the Handheld Controller. Just tap the Wizard box and follow the prompts.

TerminatorX Coyote Fox Body Wizard Engine Type

Select your engine type. In this case, Ford Coyote.

TerminatorX Coyote Fox Body displacement selection

Select engine displacement…

TerminatorX Coyote Fox Body target idle speed

… and then your preferred Target Idle Speed.

TerminatorX Coyote Fox Body camshaft duration

There are options for camshaft duration,

TerminatorX Coyote Fox Body Injector Type

Injector type,

TerminatorX Coyote Fox Body DBW selection

And drive-by-wire (DBW) selection. Other options include choosing transmission control or adding in various power adders like nitrous oxide, turbocharging or supercharging.

TerminatorX Coyote Fox Body spark timing

The simple Spark Timing screen prompts for values at idle, cruise, and wide-open throttle, as well as cranking timing.

TerminatorX Coyote Fox Body throttle sensitivity setting

An interesting feature of the drive-by-wire provision of the Terminator X Max is the ability to control the pedal vs. throttle response. For instance, you could set a gentle throttle response to the beginning of the pedal movement and then cause the throttle to respond much quicker the more the pedal is depressed. In other words, you can make the throttle response as touchy or as soft as you like.

TerminatorX Coyote Fox Body engine monitoring

The handheld controller is also used to monitor all the vitals of the engine in real time. The screen is customizable so you can pick the parameters that you need to monitor. Data logging is also available via an SD card slot in the controller. This screen is not required to run the engine so it can be unplugged once you are satisfied with the performance of your tune. At that point the learning mode should be turned off so the setup that you are satisfied with does not get altered later on down the road.

TerminatorX Coyote Fox Body ECU and Ti-VCT LED lights

Both the ECU and the Ti-VCT controller have indicator lights that will let you know at a glance that everything is functioning normally or, if the need arises, can assist in determining the cause of a fault.

TerminatorX Coyote Fox Body Finished Product

The finished installation makes this Coyote look like it might have been an option in ’88 Mustangs. And it will perform just as well here as it would have if delivered in a new car straight from Ford.


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