Last Updated
15 September, 2004

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Installing a 
J&S Safeguard Ultra II

The J&S knock sensor is a sophisticated black box (actually blue) that monitors your engine for knock and then retards the ignition of the offending cylinder in response. According to the manufacturer, it can respond within 1 RPM of detection, and can retard a single cylinder as opposed to all cylinders.

The original Safeguard had many advocates, and when an upgraded version was made available by ATS Racing, through a GP, I picked up the Ultra II version. This version adds a "boost retard" feature (which I'm not I'll be using) and a fuel cut defeat. I bought the higher priced Ultra II to get the fuel cut feature, since I had not yet installed a fuel cut device. I had already purchased (but not installed) an HKS FCD, but one less box is desirable. The FCD is for sale if anyone is interested.

This unit was installed as part of a larger project which included an APEXi AVC-R boost controller, GReddy Intercooler, SPAL IC fan, GReddy Oil Catch Can, and some gauges. Because of the scope of my project, some of the photos might show more disassembly than is actually required. It's also likely that the photos don't always match EXACTLY what's in the text. As is often the case, I would have changed the sequence of a few things if I had to do it over again. 

Finally, remember that this is only a guide -- not gospel. What you do to YOUR vehicle is YOUR responsibility. I do not endorse, approve, authorize, or otherwise encourage you to make alterations to your vehicle. Be careful, and recognize the dangers associated with modifications to your vehicle's critical systems, like electrical, engine, brakes, etc.

Please contact me if you have comments or suggestions about the article or the project, or if you find errors on these pages.

Tools/Materials Needed

  • Soldering iron & solder (low wattage)

  • Phillips and flat-bladed screwdrivers in various sizes

  • 10mm and 12mm sockets with assorted extensions

  • Sharp Xacto knife or similar cutting tool

  • Wire cutter/stripper tool

  • Electrical tape

  • Assorted wire ties

  • Ribbed cable sleeving (Optional)

  • Braided cable sheathing (Optional)

  • 10 feet of 22 AWG hookup wire in 7 or 9 different colors (Optional)

Doing It

The hardest part of this installation is running the wires through the engine compartment into the cabin. This can be greatly simplified if you decide to mount the J&S alongside the ECU in the car's trunk. However, that makes adjustment difficult, especially during the initial setup.

I chose to mount the control unit in the upper compartment of the rear console. Here's a photo of the finished installation:
JS_Installed-01.JPG (67754 bytes)
This location was perfect for me. The unit fit just right, with enough room at the rear to install the vacuum/boost line. Since the wires come into the cabin through a bulkhead grommet just below the console, it meant I didn't need to run wires to the dash. I DO plan on running the LED monitor wires to the A-pillar gauge pod when I receive the monitor unit, but that's probably only one or two wires.

I used some Velcro strips to keep it from sliding around. Just a few hold it tightly in place.

Routing Wires Through the Firewall

Since I was routing wires for multiple devices, plus a hose for the boost gauge and Safeguard unit, I decided in advance that I would sort everything out and do it as well as possible.

I had 7 wires for the Safeguard control unit, 6 wires for the AVC-R control, 3 wires for the IC fan switch, 2 wires for a future EGT gauge, plus a boost hose. This was going to require some serious work to get these through the firewall without opening more holes.

I enclosed each bundle of wires in a braided cable sheath. This is an expandable cable sleeve perfect for routing groups of wires. It comes in a variety of sizes and colors, although it is fairly expensive (about $3 to $5 per 10-foot length for the sizes I used). It's available at McMaster-Carr as "Braided Polyethylene Mesh Sleeving".

The braided sheath is fine for most uses, but is not suitable for protecting the wires inside the engine compartment. For this, I used what the factory uses - ribbed sleeving. You can buy this at several sources, but McMaster-Carr carries all different sizes. It's called "Slit-Convoluted Polyethylene Conduit" in their catalog. I had purchased several sizes over time. Unfortunately, McMaster-Carr only sells this is 25' lengths. Fortunately, the smaller sizes are what you need, which reduces the cost.

Once I had prepared the wire bundles, I had to choose an opening in the firewall. The first task was to remove the rear and center consoles in the cabin. 

The rear console is secured with four Phillips-head sheet metal screws, which are easily removed:
Rear Console 02.JPG (44991 bytes)
The center console has six retaining screws. Four of them are hidden under plastic caps near the rear of the console, two on each side. Here's a photo of one of them:
ConsoleSideScrew.JPG (64767 bytes)
Using a small, flat-bladed screwdriver, slip the blade behind the plastic cap and ease it off. They are quite secure, so be careful not to damage the console in the process.
Now you can remove the shifter boot, which is easily snapped out of the retaining panel:
Shifter 02.JPG (71907 bytes)
Next, remove the retaining panel. This panel is also snapped into place, but you'll need to work your fingers around the perimeter of the opening to carefully unsnap each of the snaps, as they are quite firm. You can then remove the panel:
Shifter 03.JPG (87545 bytes)
I chose to remove the shifter knob to get things out of the way, but it's not a requirement.

Looking at the previous photo, you'll notice two Phillips screws on a metal brace at the front of the console. Remove these screws and the console should come free.
I decided to run my bundles through the large rubber grommet that routes the shifter cables. It's located on the lower left of the firewall, just above the console tunnel:
Firewall Grommet 01.JPG (134115 bytes)
This seemed to have some room for additional cables, if I drilled or cut some additional passages through the grommet.
I removed the two 10 mm nuts that retain the grommet cover, and removed the grommet. The holes for the shifter cables are angled through the grommet, so it's not a simple hole-cutting process. I had great difficulty making a new hole in the grommet due to its soft composition. Drilling was useless, and I ended up cutting an opening using an Xacto knife. It's a trial-and-error process, but here's the finished product:
Modify Grommet 01.JPG (52128 bytes)
I could tell that I would need to grind away a bit of the metal cap to avoid stressing the wires, but it looked like this would work.
With the inside work finished for a while, I turned to the engine compartment. The heat shield panels on the firewall would need to be removed. This looked fairly straightforward, which I learned was another illusion.

In my case, I had already removed the intake assembly and the turbo-to-intercooler pipe. You'll need to remove the intake assembly at a minimum, and removing the intercooler pipe will gain access to the heat shield fasteners.

The heat shield consists of two metal panels, held on with 10 mm nuts/bolts. While they are difficult to reach (this is an MR2, remember), I managed to get them all removed. Here are a sequence of photos which show the mounting points:
Heatshield-01.JPG (60385 bytes)
HeatshieldScrew-05.JPG (62627 bytes)
Heatshield-02.JPG (68271 bytes)

There is a remaining nut that I could not get a photo of, which is located directly below the turbo. While the nut was not impossible to reach, the problem was that the larger (upper) heat shield panel had an integral stud attached. This stud prevented the panel from being removed, as the shifter cables were blocking it.

I messed around with this for about an hour before I decided to jack the car up and loosen the shifter cable bracket from underneath. Here's the location:
ShifterBracket-01.JPG (64692 bytes)
There are two 12 mm nuts attaching the bracket. Once these are removed, you can lower the car and move the cables out of the way of the heat shield stud.

With the heat shields removed, you have access to the central tunnel:
UnderHeatshield-02.JPG (68753 bytes)
I fed the wires and hose through the opening, then reattached the grommet to see how things fit. I then enlarged the opening in the grommet until I felt comfortable that nothing was chafing and that the shifter cables were not rubbing against the additional wiring.
Here's a photo of the wiring at this stage:
ConsoleWiring-05.JPG (94876 bytes)
I bundled the wiring for the IC fan switch and the EGT gauge with the braided sleeving. I removed the existing ribbed sleeving that ran along the left side of the console tunnel and under the instrument cluster. I then took some new ribbed plastic sleeving and wrapped the new wire bundle, the boost gauge tubing, and the existing wiring. Here are some photos of the results:
Pull Wires 05.JPG (74350 bytes)
Pull Wires 06.JPG (74458 bytes)
I needed a boost hose for the Safeguard unit, so I put in a tap on the boost gauge line. The boost gauge line is 1/8" nylon tubing which uses compression fittings. I added a T-fitting which included a nipple on the T:
Boost Line Tap 01.JPG (104954 bytes)
I then added a length of silicone vacuum hose to the nipple:
Boost Line Tap 03.JPG (91919 bytes)
This hose will attach to the back of the Safeguard unit.
At this point, I decided that the 18 AWG wire that was provided with the Safeguard unit was unnecessarily heavy for the job it performed. The bundle was a bit too thick and inflexible. I decided to pull 22 AWG wires through, using the original bundle as the "puller". This actually went off without much of a struggle, and I had a bit more working room in the grommet.

The connectors supplied by J&S made it simple to remove it from the 18 AWG wires and reattach to the 22 AWG wiring. I pulled through enough of the wiring harness to ensure I could reach the Safeguard control unit after it was mounted in the top of the rear console. I then turned my attention to the wiring in the engine compartment.

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