15 September, 2004
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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.
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:
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
The rear console is secured with four Phillips-head sheet metal screws,
which are easily removed:
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:
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:
|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:
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:
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
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:
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:
|With the heat shields removed, you have access to the
|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
|Here's a photo of the wiring at this stage:
|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:
|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:
|I then added a length of silicone vacuum hose to the
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
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