The Situation:
My car is an Acura Integra GS-R, and the engine has two really nice features: VTEC & IAB
The Honda engineers that desgined this car's engine have made one awesome piece of machinery. The car designers,
however, left out something that many Integra owners would love -- indicators for when these systems engage.
If you don't know what VTEC and/or IAB stand for, or what purposes they serve, then you need to go do a bit of research. There is tons of information out there, though some of it is incorrect, so here's a quick 'n dirty explanation:
VTEC = Variable Valve Timing and Lift, Electronic Control
IAB = Intake Air Bypass
Don't ask me why it isn't called VVTLEC, I guess that's just to hard to say compared to 'vee-tek'. Anyway, it's a
system that activates an alternate cam lobe, thus altering the timing and lift of the valves. This basically allows
the engine to run very smoothly and efficiently at low RPMs, and produce much more power at higher RPMs.
The intake manifold on the GS-R has two paths that the air can flow through -- a short one and a long one. At very
high RPMs the secondary path is opened up to allow the engine to breathe easier. This, in conjunction with VTEC,
helps the engine produce even more power.
These systems are controlled by the car's computer (aka Engine Control Unit or ECU), and engage under certain situations that take into account factors such as RPMs, speed, coolant temperature, etc. To know exactly when this happens, I have wired two 12V LEDs into the car, one for each system. I chose to put them on the center console, just under the A/C vents, between the flasher & defrost switches. I also wanted a way to disable the LEDs, so I also wired in a switch near the handbrake.
| To accomplish this, I had to remove the entire center console, glove box, kick panel, passenger side carpeting, and more. After doing all this, the car looked something like the pictures at the right & below. Here you can also see some of my high-tech [smirk] probing equipment which helped me determine which ECU wires to tap into. |  |
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After removing all these parts, I brought them inside to my...uhm...workbench. With an array of top-notch,
high precision tools (screwdriver, soldering iron, wire tags, paring knife, glass cutting board,
and a small food dish), I went to work.
The A/C controls had to be removed from the panel so I could get the drill in there to make some holes. |
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After attaching wires to the LEDs, mounting them in the holes, and putting the A/C controls back into the panel
I was making good progress.
Here's some picutres of the work so far showing the front side, back side, and a really close-up shot of the LEDs. |
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You might have noticed in the picture above that I used 2-pin molex connectors all wires for easy disconnection
in case the car needs to come apart for service or futher hacking. This also made connecting the wiring between
the various places really easy. I also color-coded all connectors according to my professionally done schematic,
which you can see at the right.
Now with the center console put back together the car is looking more normal, but with a couple of nice additions. |
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| After much agony trying to figure out which wires on the ECU were the correct ones to tap into for the signals, I got the LEDs working perfectly. I took some pictures of it in action, here's a cheesy animation of what it's like going from idle, into VTEC range, VTEC+IAB, then back down. |
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Final Thoughts:
I finally got smart and disconnected the ECU & some wires under the hood and just traced the right ones from end to
end using things such as telephone wire & paperclips. That worked like a charm, and now I've got my indicators!
The hardest part of this project was figuring out where to connect my LEDs to the ECU. I had several conflicting
diagrams and text references of ECU pinouts from all over the 'net. Turns out none of them were correct.
In fact, they weren't even close!
Go back to Dr. Cheap's House of Hacks!
