i-vtec light for 2008 Civic R18 (LED indicator when 'Eco' cam profiles in use)

[uabcar]

Hi all- I'm new to the forum. Been lurking for a while. Lots of great tips. I bought a SCII as a result of this site- and love it. Really helps to make a game out of getting better gas mileage.

Last fall I bought a new Civic EX- so it's got the R18 with i-vtec. I've been reading about this great little motor and want to implement an 'eco mod'. I want to add a green LED to the dash that lights up to indicate when the motor has engaged the 'Eco' cam profiles.

I've searched this forum and found a couple references to people thinking about it but not found anything of substance. If someone can point me in the right direction (maybe a DIY, or even some sort of wiring diagram for the solenoids)- I would very much appreciate it.

I understand that there are three solenoids that drive the v-tec system however I'm not sure which one does what- and if any one of them can be tapped etc.

Thanks in advance.

BTW- I'll gladly do a DIY on this- with pics etc. if someone can help point me in the right direction.

[SVOboy]

I'm not sure that I've heard of it being done before. Do you have any wire diagrams to look at? If you could post some we could probably figure it out easily enough.

Or trial and error with LEDs on the different solenoids,

[KJSatz]

As an owner of an 8th-gen Civic LX, I wish you luck on your travels! If you figure it out a how-to would be most excellent and appreciated .

[evolutionmovement]

Is it like other VTEC where you can just feel the difference? 3 solenoids—are there 3 different cam profiles on these engines?

[uabcar]

Originally Posted by evolutionmovement

Is it like other VTEC where you can just feel the difference? 3 solenoids—are there 3 different cam profiles on these engines?

The R18 is different than most (all?) other Honda vtec motors. In the case of the R18, the motor is in std/power mode most of the time. If certain criteria are met and the engine is between about 1500 and 3500rpms, then vtec will engage the economy profiles. I want to add an LED indicator for then this happens.

In most other vtec engines, like the SI- you can feel and hear when the high performance cam lobes kick in at 5000+ rpms.

I'm somewhat surprised that this has not been done more often. While researching this I came across a pretty detailed thread where it was done on a Fit.

[brucepick]

Hmm.
I drive a '97 HX with a D16Y5 engine.
I've been using the ScanGauge to detect LB but a dash light would be ideal.

Maybe one can tap into a solenoid on that engine to learn when it's in lean burn?
OK, I'm wandering off topic. But I thank you for the idea!
The D16Y5 has only two modes. Might be a bit easier to determine which solenoid is responsible.

[uabcar]

Originally Posted by brucepick

Hmm.
Maybe one can tap into a solenoid on that engine to learn when it's in lean burn?
OK, I'm wandering off topic. But I thank you for the idea!
The D16Y5 has only two modes. Might be a bit easier to determine which solenoid is responsible.

From what I can tell, the R18 has two items that look like solenoids. One on the top has a two wire connector. I tried to tap into this one (actually just disconnected it and attached my volt meter to the two terminals). In this test, the connector was not attached to the solenoid so that may have been the reason my results were somewhat inconclusive. During this test, I got a constant voltage of 3.2-3.8 volts. Did not seem to change based on rpm. I did notice that the engine stumbled when I hit 3500rpms though. I backed off right away and was not able to glance over at the volt meter.

The second (and third?) solenoid has three wires going into it. I assume this to be two 12v positive leads and a ground. Unfortunately this solenoid(s) is located on the lower backside of the motor (pass side) and there is no slack in the wire/connector so it's not going to be as easy to test.

My guess -a total guess really - is that the two solenoids at the bottom are involved with engaging the econ lobes and the one on the top disengages them.

Ideally someone with a factory service manual can help identify the leads from the main wiring harness.

[evolutionmovement]

Could you not also hijack the system to manually engage the eco-profile? There might not be any advantages, but that would depend on how conservative Honda was in defaulting towards the power end of the scale. Interesting engine. I'll see if a mechanic friend has an FSM for this and post the solenoid locations if I can.

[uabcar]

Hey everyone- I figured it out - with the help of a guy on the 8thcivic forums who has a FSM.

I'll more detail later (or if you like there is a thread in the mechanical/technical forum where I've discussed it in some detail).

It turns out that the wire you need to tap is right on top of the engine. Per my earlier post containing a link to the picture of the i-vtec setup, the solenoid on top has two wires going to it. On my car (2008) these wires are black and black w/a white stripe. You need to tap the black w/white striped wire. This will give you a positive signal for the LED (and you then ground the other leg of the LED).

I've got it rigged up temporarily but plan to complete everything this weekend. I'll be adding a relay, fuses and resisters to the circuit when doing the permanent install.

This is a very cool little mod as I can now monitor when I'm in econ mode and not.

One quick observation, even when below 3500RPMs on the highway, if you are over 70-75 (which is a bit above 3k on my 5MT EX) you have to be very light on the gas. You have a bit more room in the 55-65 range before it will disengage.

[KJSatz]

It's so great you got it working! Can't wait for more details.

Is it at all possible to accelerate while keeping the light on?