A'PEXi's Auto Timer for NA and Turbo cars is one of the most sophisticated idle-down devices we've seen.
Unlike other brand-name timers, the Auto Timer receives an input from your (EFI) car's exhaust oxygen sensor to determine the appropriate idle-down time. That means the engine won't be left idling for minutes after its barely raised a sweat, and - conversely - it'll have long enough to cool after you've been giving it a thrashing.
It thinks for itself.
In addition to its self-timing abilities, the Auto Timer has a couple of other attractive features - a battery voltage display and an oxygen sensor display (showing output millivolts and an approximate air-fuel ratio).
A simple egg timer it ain't...
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Ooops!
We did intend to carry out a full installation and test of the unit, but we ran into a rather major problem. The device won't work with oxygen sensors of the titanium type... and guess what. The VL Commodore Turbo that we did the complete installation process on turns out to have a sensor of this sort! Unfortunately, we ran out of time to do another install, but the process that you'll need to follow will be fairly clear from the following words and pics. Just check that your car's oxygen sensor has a 'normal' 0-1 volt output before buying the thing....
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1. Installation
The Meter requires the following connections:
- Earth
- Handbrake switch
- Oxygen sensor signal
- 12V permanent feed
- 12V accessories
- 12V ignition
Before beginning installation, check you've got a few vital items - a legend for the ECU pin-outs and the A'PEXi instruction manual in English (available at Auto Timer Instructions). It's also handy to have some spare lengths of 4mm hook-up wire, connectors, a multimeter and a soldering iron.
Oh and, when working with auto electrics, it's a good idea to disconnect the negative battery terminal before getting started.
Begin by finding an earth on the ECU - this connects to the black lead sprouting from the Meter's Control Box. Then, if you've already removed the ECU from its mount to hook up the earth wire, you might as well connect the Meter's oxygen sensor input next.
The A'PEXi instructions show ECU pin-outs on an assortment of Japanese cars; all you need to do is connect to the specified oxygen sensor wire. If, however, your ECU pin-outs are not shown in the instructions, it's wise to grab a wiring diagram to locate it. Failing this, you can always probe the ECU connector with a multimeter.
Connect the oxygen sensor input to the white lead from the Control Box.
Next comes feeding the handbrake switch input to the Meter.
One way to do this is to remove part of the instrument cluster's surrounding trim and connect to the wire from the handbrake switch (ie the connection that is earthed when the handbrake is on). Again, access to a factory-wiring diagram makes this easy.
The handbrake input connects to the Control Box's grey lead.
Now it's time to hook up the wires that plug into the unit's 3-pin connector - the 12V permanent feed, ignition and accessories.
The easiest way to do this is to strip the steering column trim and make each of these connections up near the ignition switch. Again, access to a factory wiring diagram makes wire identification easy, but it's still a breeze to find these wires for yourself. Grab your multimeter and probe the wires until you identify one with a permanent 12V, one that energises with accessories and one that energises with ignition.
If it gets hard to fiddle with the bunched-up wires once two of the connections have been made, there's no reason why you can't tap the third one in somewhere else. After making the accessories and ignition connections, we ran a wire through the firewall and hooked (through an in-line fuse) directly onto the battery for our 12V feed.
And which connection goes where? The 3-pin connector's red, green and blue wires go to the 12V, ignition and accessories respectively.
Congratulations. You've just wired in your A'PEXi Auto Timer.
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An optional off-the-shelf adapter harness and plug...
A'PEXi offers an adaptor harness - which plugs straight into the ignition switch wiring of certain Japanese vehicles - as an extra-cost proposition. This connects the 12V, accessory and ignition feeds to the Control Box in one easy (and neat) step. Check for availability.
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2. Adjusting the Presets
With the battery's negative terminal re-connected, your A'PEXi Auto Timer will shine its LEDs at you; you can now you can customise its presets. (Note - as an in-built safety feature, the handbrake must be activated before you can alter presets). Push the joystick up or down to scroll through the Meter's operating modes - battery volts,
timer, oxygen sensor millivolts and air-fuel ratio.
Setting the Low Voltage Warning
Click up to battery mode and the current battery voltage is displayed.
Hold the joystick to the right and the battery mode LED will start flashing. Next, push up or down on the switch until you reach your desired low voltage warning. Hold the switch to the left to set it.
From this point on, a battery voltage lower than the value you've selected will cause the display to flash.
Setting the Auto Timer
The Auto Timer function takes into account your driving behaviour (as determined from the oxygen sensor) and sets the idle-down time accordingly.
Click down to the Time mode and this is the display you'll see. Hold the switch right (which will make the Time LED flash) and then click up or down to adjust the left and right numerical values - these are the maximum and minimum idle-down periods. Next, switch to the middle position and scroll between L, N and H - these letters (representing Low, Normal and High) will fine-tune the idle-down period between the minimum and maximum presets.
Example: 4n2 means the engine will idle-down for a 'centre weighted' time between 40 and 20 seconds.
As before, confirm your settings by holding the switch left.
Setting the Turbo Timer
In the instance you might want to over-ride the Auto Timer, you can manually set the Turbo Timer function.
Again, use the joystick to click down to the Time display and then click twice to the right. The Time LED will start flashing. A display something like 0.30 (30-seconds) will be displayed, but toggle up or down to set your default over-ride period.
Once you've arrived at the duration you want, hold the switch left to confirm.
Setting the Air-Fuel Ratio Display
Click up to the 02 display and you can see the oxygen sensor's output voltage. Click up once again and the display shows the Meter's calculated air-fuel ratio (as derived from the oxygen sensor output voltage).
Note that, as delivered, the Meter has something of a 'base map'. For better accuracy, the displayed air-fuel ratio requires calibration against another air-fuel ratio meter.
There are two ways to calibrate the Meter - by adjusting the displayed air-fuel ratio to suit a given sensor voltage, or vice versa. To adjust the sensor voltage to suit an externally measured air-fuel ratio (from a wide-band sensor), click down to the 02 display mode, hold the switch right and then adjust the air-fuel numbers to suit each voltage increment. The air/fuel ratio is displayed in increments of 0.1, while the oxygen sensor voltage steps are only 5 millivolts.
Once 'mapping' is complete, hold the switch left to confirm.
Note that this air/fuel ratio display is not temperature compensated, so its accuracy at different engine loads isn't great.
Mounting the Display and Control Box
The Auto Timer is a very flexible package. You can mount the Control Box under the dash (using the supplied double-sided tape) and the display is small enough to fit in almost any position on the dash. Again, use the double-sided tape to secure it into position.
An ideal location is out of window-sight and out of direct sunlight.
Summary
Selling for AUS$297 (US$150.76) through the AutoSpeed shop, the A'PEXi Auto Timer is an attractive and very well built gizmo. You get an advanced idle-down timer system and a semi-useful air-fuel ratio display and a battery voltage meter.
It really is much more than "an expensive turbo timer".
Yes - with all of its 'bonus' uses - the A'PEXi Auto Timer is a good value buy.
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Beware
The air-fuel ratio function of the Auto Timer will not operate on vehicles with a titanium type oxygen sensor (such as R32 Skyline GT-R, S13 Silvia/180SX and Commodore VL turbo). In addition, those vehicles that don't idle at around 14.7:1, use a non-heated (single wire) oxygen sensor or have the aforementioned titanium oxygen sensor won't interface with the unit's auto idle function. Lastly, the A'PEXi Auto Timer is not compatible with all engine immobilisers; ask your immobiliser agent for details.
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