Installation of the Quarterhorse on an 89-93 Mustang EEC

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Installation of the Quarterhorse on an 89-93 Mustang EEC

Postby cgrey8 » Mon Jan 26, 2009 7:06 pm

Before following these directions, make sure you've read over the FAQ about Things to know AFTER buying a TwEECer or Quarterhorse.

The physical installation of the Moates Quarterhorse, or QH for short, into an older 89-93 era EEC is not as straight forward as installing a TwEECer or installing the QH in the newer EECs. There are a number of components on the circuit board that need to be bent out of the way to make room. This tutorial will walk you through each step as I experienced it with my A9P. I expect all the GUFx and similar era processors to have the same challenges. And as always, when messing with J3 connected devices, always make sure neither the EEC nor the device are connected to power of any kind. And yes, a USB connection to a computer counts as being connected to power.

First off, you need to remove the EEC's cover. My A9P's cover is held on with Torx screws. The top has 4 T-15 Torx screws and the back is held in place by 2 T-10 Torx screws. I found that not all T-10 Torx bits are created equal. My set of quick-insert Torx bits wouldn't fit the T-10 screws on the back of the EEC, but my T-10 Torx driver (looks like a screwdriver with a Torx end) worked. So don't be surprised if you find your T-10 doesn't fit exactly and you have to find one that does OR get creative at removing the screws.

Once the screws are removed, the case top should lift right off. There may be some of that silver "WARRANTY VOID" tape holding the case top to the EEC base, but that should peel right off.

This is what the EEC looks like with the top off. If you don't see images below, you may need to LOGOUT of the forum and view this page as a guest:
Notice the edge-connector on the right of the circuit board. This is where the QH will install. Unlike the TwEECer, which hangs completely external to the EEC, the QH installs inside the EEC with only a 1/4" or so of the device protruding outside.

The factory puts heavy grease on the exposed metal of the J3 edge connector to protect the exposed metal from corrosion. But sometimes the grease can attract dirt and particles that will need to be cleaned off. Q-tips and some alcohol or your solvent of preference should clean the connections up without much trouble. I personally use QD Electronics Cleaner which doesn't leave residue like rubbing alcohol can.

If you line up the QH up next to the edge connector, the 1st interference challenges should be quite obvious:


Once you take care of those, you should have another component at the very tip-end of the QH:

Next, you have a small black transistor that will want to cause trouble:

With some gentle nudging, all those components should bend right out of the way just enough to make clearance for the QH to fit onto the J3 edge connector as you see here:


As you can see a few pictures up, I had this guy bent down the other direction, but it still wasn't out of the way good enough. So I tried bending him back as you see it here and this worked out much better.
I was really worried about breaking the leads off after I'd already bent it in one direction. It worked out fine, but do try to reduce the amount you stress the leads. These are 15-20 year old components and the risk of breaking a lead is very real, but unlikely if you are not too forceful.

There's a final interference, but it's not one you'll likely have to worry about.
In this picture, you can see the QH butts right up against the side of a regulator. By the time the QH makes contact with the regulator, it is all the way onto the J3 edge connector. So there's not much you need to worry about with this guy. It's a good thing because that regulator's leads are quite thick and don't yield nearly as easily as the other components.

With the QH fully installed onto the edge connector, you can attempt to connect the supplied USB cable to find the next offenders:

They should bend right down out of the way no problem:


Early on, Moates supplied the Quarterhorse with USB Cables that had a large ferrite bead (aka wire-wart) noise filter (pictured). You've likely seen ferrite bead bulges on laptop power cords and other various computer cables. The cables that came with the big ferrite bead already on the wire were not USB2.0 compliant and often caused connectivity problems with the Quarterhorse, which is attempting to connect with the laptop at USB2.0 speeds. If you have this type wire, Moates highly recommends replacing this wire with their much thicker USB2.0 compliant cable which DOES NOT have a ferrite bead installed. However Moates does supply USB2.0 friendly ferrite-beads that are much smaller than what's pictured for you to install on the wire yourself. It is recommended that 1 ferrite bead be installed just outside the EEC and another a few inches from the USB connector that plugs into the PC. The USB2.0 complaint cable and ferrite beads weren't available when these pictures were taken.

Route the cable between the QH and the EEC circuit board. This is much easier to do with the newer cables that don't have that ferrite-bead in the way:

Put the EEC's case back on:

At this point, I thought I was done. But when I flipped the EEC over, I noticed something. The cord is coming out of the EEC right next to the sharp edge of the top:

To fix that, I put a very slight bend in the case with some needle-nose pliers:
The case top is so flimsy, you can almost do this with your fingers. If you want added protection from chafing the wire over time, you can liberally wrap the wire in electrical tape or even put some hot glue in between the wire and the case to help protect it.

Finally, notice how the QH has electrical connections exposed outside the EEC. You may wish to wrap the exposed portion of the QH with electrical tape or cover it in hot glue just to make sure an accidental touch against the body of the vehicle or a possible stray wire under the dash doesn't cause you grief at some point. Again, that's completely up to you as to how you want to deal with that. Also note, your Quarterhorse likely has a black connector soldered to the exposed electrical leads. This is where an optional tune selector switch is connected to the Quarterhorse. The early model Quarterhorse pictured didn't have that provision.

As for the installation, that should do it. You can put the screws back in and reconnect the EEC back to the vehicle's wiring harness. As a suggestion before you completely reinstall the EEC back into the kick panel, make sure it all works and takes a download of your tune. This will require you have your EEC's tune in a *.BIN or *.BEB format, the latest version of BE that has Quarterhorse support, or some other software tool that also supports the Quarterhorse. For those of you that have been working with BE on a different tuner like the TwEECer or Moates Chip, BE should download your current tune without any trouble. For people brand new to tuning, you'll want to download your EEC's stock tune. Stock 89-93 Mustang tunes are included with BinaryEditor and are also available for download from the BinaryEditor website in *.BIN format. If you do not have your EEC's tune in file format, you'll need to find your tune or extract your EEC's stock tune using Moates hardware (refer to for pricing and details on exactly what you need).

There may be other tuning softwares available that support communication with the QH, but BE is the only one I'm familiar with. Refer to for more details on what your software options are for the QH.

And as a reminder, in case you forgot or didn't read the thread mentioned at the very beginning, new Moates Quarterhorses are shipped blank. So before it will run an engine, a tune needs to be written to it. Common behavior of a blank QH is you hear the fuel pump run continuously with the ignition turned ON. The fuel pump should only run for about 1 second, then turn OFF if the EEC is operating correctly.

For these 89-93 Mustang EECs, it is recommended to configure the Quarterhorse to Mode 2 and fill all 8 tune positions with a tune, even if it is just the stock tune. As of this writing, there's also a bug in the Quarterhorse firmware that is being looked into where the tune the QH serves to the EEC may not be the same tune you are commanding using BE or the hardware dial. It is highly recommended that you datalog tune position so you get positive feedback that the tune you want to run is the one the QH is serving to the EEC. To read more about this issue, read this thread:
Possible Tune Selection Bug in QH firmware
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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