Holley Terminator X - What to Know Before Installing

This is something that is well documented in general, but not fully detailed for the e9x chassis swap.  Some have documented how they did it, but it still seems many people contact us with questions they feel are left unanswered.


But in all seriousness, this is one of the biggest issues with first time users wiring there Terminator X Max.  This wire is intended to be connected to a brake switch.  It is a safety measure for DBW that in the case something went wrong with the gas pedal, once the brake is applied it limits the amount the throttle can be opened.  A lot of users leave this wire disconnected for power braking, boost building, etc.  I would recommend if you are daily driving your vehicle to connect it to a switch or relay so when street driving the car you can maintain the safety aspect, but still easily disconnect it for track use. (Future wiring diagram to come)

Now that we are past RULE #1 lets look at some of the other common questions and issues.

What kit do I need?

This is based off several factors. What 24x or 58x crank? EV1 or EV6 injectors? Drive-by-Wire? Transmission control? Answering those questions will lead you directly to the kit you need.  The only other options are if you want a 3.5" handheld or not.  This is a personal choice but if you intend on running a larger display like the 7" Digital Dash then you may have no need for the handheld.

Throttle Body & TPS Autoset Errors?

This again is very common.  In the case of this refer first to RULE #1.  If that is not the issue than move on to checking your wiring connections to interface with the BMW gas pedal.  One easy way to avoid a lot of the TPS Autoset issues is to purchase a real GM Throttle Body.  You can't go wrong with LS3 throttle body GM Part # 12605109. Many eBay and Amazon clone throttle bodies cause issues with the TPS Autoset, which must be successful for the engine to run.

Which sensors are a must?

Besides the basics (oil, coolant temp, crank, cam) you must have a IAT (intake air temperature) sensor for the Terminator X. We recommend the Holley IAT sensor Part # 534-20.

We also highly recommend a fuel pressure sensor.  If not at minimum a fuel pressure gauge.  It is very important when tuning that you know the exact system fuel pressure.  A lot of tuners will require you to verify this.

Where should I get power for the Terminator X?

Holley in the install manual requires the main ECU power harness be connected directly to the battery.  Others have connected it to the power tap location in the e9x under the hood on the passenger side. The issue with doing this is if you would ever need Holley technical support, they will most likely as how you are powering the ECU, and if it is not a direct battery connection request that you move it to the battery.  The other issue is some tuners (mostly in person dyno tuners) may find it to be a concern prior to tuning the vehicle.  These are just things to keep in mind when deciding how to power the ECU.

Where should I mount the ECU?

One of the easiest and cleanest locations to mount the Terminator X ECU is in the glove box.  Best part of this location is it has easy access to the BMW engine bay electrical box, which is now nearly empty, to route your harness, gas pedal connections, etc.  You will need to take out the plastic housing and remove the cooling fan, this is no longer needed, and use the hole through the firewall for wiring.  The Terminator X harness will fit but just be sure to take your time when pushing the connectors, relays, and fuse holders through as they need to be in a certain position to fit.

We plan to continue expanding and updating this page!



Older Post Newer Post

Leave a comment

Please note, comments must be approved before they are published