An Insight FAS switch install

Discussion in 'Honda Hybrids' started by Right Lane Cruiser, Oct 4, 2009.

  1. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    After 1.75yrs of ownership, I finally decided to go ahead and install a FAS switch in my Insight. Using key FAS isn't something I find annoying or difficult to accomplish correctly (with plenty of practice in my Elantra prior to this vehicle ;)), but I have found that the 12V battery simply isn't sufficient for my needs.

    To ensure enough voltage during long FAS in my Elantra with the headlights on (and when it is cold) I've installed a deep cycle battery (Optima Yellow Top). The battery in the Insight is considerably smaller, the battery tray is smaller, and IMA depends upon some of the chemical characteristics of the 12V unit in order to operate correctly. For these reasons I don't want to install a deep cycle battery in this vehicle. Thinking of ways to augment the capacity, I briefly considered trying to hook up a spare battery in parallel from the passenger compartment but quickly dismissed it as being too space intensive and not very practical if I ever want to carry a passenger. Besides... I already have a big battery available in this car!

    There are many reasons to install a FAS switch... I did it to get the DC-DC enabling circuitry. :) Inspired by Randall's install (see his thread here) and recalling that Mike Dabrowski's MIMA system can be configured to include this functionality (see his site here), I started looking through Mike's MIMA install directions to see how to manually trigger the DC-DC functionality during a FAS.

    For those who don't know what the DC-DC circuitry is for, the Insight does not have an alternator to maintain the 12V and provide power to accessory electronics (headlights, radio, etc). Instead, it has a voltage step down circuit to bring the high voltage (144V) the IMA battery provides down to around 13.8V for the accessory system. (It actually cycles on and off as needed -- this can be seen with a ScanGauge.) For safety reasons, this circuitry is not enabled when the ignition switch is in ACC. It is also not active before the engine is started when the ignition switch is in the ON position. This means that during a key FAS the car is running on just the 12V. However, when the car enters AS (Auto Stop) this circuitry is active and the 12V doesn't run down. The FAS install detailed below allows me to trigger AS behavior at any speed I wish -- and it allows me to have the DC-DC enabled while doing so.

    One of my personal rules for Insight modification is that any changes must be completely reversible such that there is no evidence of "tampering." This means no cutting of wires! As it happens, one of the iterations of Mike's MIMA kit is implemented using what he calls "pin popping." This involves removing pins from the plugs in the existing harness instead of cutting them -- perfect for what I want! I contacted Mike to ask about acquiring the correct pins and tool to create my own DC-DC enable wiring, but I ended up purchasing the extremely well constructed FAS kit instead.

    Let me tell you, it has been well worth the money!!!

    (Click on any of the images below to see a bigger image.)


    Here's what the kit included:

    FAS circuitry and pre-measured wiring with adapter pins.
    Wiring tubes.
    A Pin Popping tool.

    It is an impressively compact arrangement, but install is a bit more involved than you may think. I decided to photograph every step of the procedure so that others can see what has to be done and how I accomplished it. Throughout the effort, Mike's instructions (available on his site) were excellent and quite detailed. If you want to duplicate what I've done, his documentation is a great guide.


    On the left you can see what my cargo hold looked like before beginning. On the right you can see the carpet in the process of being removed. The lid to the hidden cargo box simply folds back and the flaps to either side are held down by Velcro.


    Lifting the center of the carpet reveals the IMA box. This box contains the battery, the inverter, the MCM, the BCM, and the DC-DC converter. I need access to just one wire in this box, but getting to it is much more difficult than it appears at first. You can see one of the plastic clips holding the carpeting down on the box to the right.


    The hidden cargo box is just thin, flexible plastic. It can be lifted right out after squeezing it a bit.

    To the right you can see a small panel in the middle of the IMA box lid that covers a very important switch -- the master switch that can be used to isolate the high voltage battery! Since the panel was just removed that switch is in the ON position. There is a red protective cover over the black switch to prevent it from being accidentally thrown.


    Now that the master switch has been thrown to its OFF position and the red cover replaced (look closely and you can see the black switch end surrounded by red) I can proceed. There is a black bolt that has to be removed from inside that little compartment to get the IMA box lid off -- you can just make it out to the right of the "ON" lettering. It unscrews to the left.

    At the lower right of the picture to the right you can see a smaller plate that needs to be removed as well. That will come out next. The eagle eyed will notice that I put the switch panel bolts back in (without the cover) so I could keep track of them, and also that I already removed the 6 T30 bolts along both sides.


    Under the small panel (left) you can see where the optional CD changer gets installed (I don't have it in my car). After removing that panel I decided to remove the aluminum extrusion directly behind the seats to gain better access to where the stock wiring enters the IMA box.

    That extrusion isn't easy to remove. The carpet has to be pulled off of it, then quite a few stubborn bolts have to be removed. Getting the edges of the carpet back into place on reassembly wasn't exactly easy either.


    After removing even more bolts in the IMA box lid, it can finally be removed! The white stuff in the photos is styrofoam used for cushioning and non-conducting spacers. At this point you want to be sure the 12V is disconnected as well.


    On the left you can see the back of the MCM -- this is a view from over the seats looking into the back of the car. From this position the MCM is at the far left. The plug I'm interested in is the one closest to the center of the photo. To be specific, I'm interested in the green wire crossing under the brown one at the top of that plug.

    To the right I've included a shot of the plug Randall tapped into in his install -- it is just the other end of the wire I'm focused on. This is on the right side of the IMA box instead of the left. The (gray) plug can be seen to the right of center in the photo.


    How many bolts did it take to get to this point? 34!! That doesn't included the two for the IMA master switch cover or the two for the CD changer block off plate (there are 3 plastic fasteners for that one, as well).

    Moving forward, I had to remove the E-Brake cover. The DC-DC enable wires have to pass through this area on their way to the rear of the car.


    To get those wires from the E-Brake to the IMA box, a tube is inserted behind the mechanism. It follows the same path as the stock wiring and comes out in the IMA box (as seen at the right).


    Remember that other wiring tube in the FAS kit? It runs from the shift console to the E-Brake. To remove that, the knob must first be unscrewed. This takes 11 clockwise turns. 4 bolts and a couple of plastic clips later, the console comes off.


    Here is the tube next to the E-Brake (left) running forward to the shift mechanism on top of the stock wiring harness. It is routed underneath the carpet along the tunnel of the car on the passenger side.


    The next part of the install is where it starts getting interesting. The FAS kit has to be wired in where the ECU is, and that happens to be in the passenger footwell. To get there, the plastic threshold plate has to be removed, then the carpet pulled back.


    With the carpet out of the way, you can see the black, protective plate bolted over the ECU. There are 4 bolts on top, and another 2 holding the ECU box to the underside of it. You have to twist the plate slightly counterclockwise and then pull the top edge toward you to get at those last two bolts without damaging the wiring underneath. The silver box is the ECU and the wires are all plugged in along its right side.


    Here's a closer shot of those wires -- the plugs are actually identical in configuration to those found on the MCM. Those plugs are all different sizes so they can't be plugged into the wrong receptacle. On the right you can see the ECU completely disconnected.


    Ready for something other than unbolting and shoving tubes under the carpet? Here's the scary "If I mess up something might get fried!!" moment. The plug I need to work on is the second from the bottom in the photo to the left. On the right you can see the first pin removed using the Pin Popping tool (orange wires to the left of the plug). It took me a while to get this one out, but after that the rest released pretty smoothly.

    [FIMG=LEFT][/FIMG][FIMG=RIGHT][/FIMG]Here we go! The left image shows the first FAS kit connection. The FAS kit orange wire goes into the plug where the red wire came out. The red wire connects to the orange/black wire inside the clear tube. This routes one of the injector signals through a relay before sending it out to the actual injector. All connections use the NC (Normally Closed) switches in the relays so that when no power is applied to the FAS switch hardware all connections are the same as the stock wiring... just longer stretches of wire.

    On the right you see the result after wiring in the other 6 connections. The green wire extending from the center of the photo to the lower right is an extra wire I added to take over CalPod functionality. It isn't hooked up to a switch yet but will be as soon as I figure out how to mount it next to the FAS switch. Meanwhile, my original CalPod switch remains connected. Both implementations simply ground the clutch switch signal.


    There are 4 wires that now have to be routed -- the green one is for a CalPod switch, the two white ones are the DC-DC enable lines, and the brown one extended by a red wire is for activating the FAS switch.

    I twisted all loosely together and then routed them on top of the stock harness, taping every once in a while. You can't see it, but the relay portion of the FAS kit is at the very top right of the photo to the right, above the top ECU plug.


    The wires continue on top of the wiring harness, under the carpet on the tunnel, along the side of the shift mechanism. At the side, the white wires dip into the tube to be routed through the E-Brake area and on into the rear of the car to emerge in the IMA box. The red and green wires stay at the shifter because I want a "stealth" install. I intend to mount my switches under the shift boot and directly on the shifter rod itself.

    How do I do this? Well, I start with a section of heat shrink for insulation.


    Add a switch, a black wire which is run back to a mounting bolt on that metal framework in front of the shifter for a ground, and cover it with another piece of heat shrink with a hole in it. A heat gun snugs everything up. (The flash makes that red wire appear orange.)

    What the heck kind of switch can be mounted this way you ask? A surface mount switch you can find at RadioShack (link here) which is normally used for something like a reset button on a circuit board. Check out the size when compared to a dime!


    Moving to the back of the car, we finish by hooking up the DC-DC enable wires. The green wire is removed from the plug and routed through the relay instead.

    After all of this, there is a lot of bolting back together... but it is all just the reverse of disassembly.

    So... how does it work? Quite well!! Despite the diminutive size of my chosen switch I can hit it quite reliably. If I key FAS I can hit the button and the DC-DC comes online -- I can see the instant jump in voltage on the ScanGauge. :D If I use it during engine on time, I have to hold it until the engine has died and then the engine will start under any circumstances it normally would when the car is in stock Auto Stop mode. The green Auto Stop light doesn't always light below 22mph (I haven't figured out why yet), the DC-DC stays on constantly instead of kicking in and out depending upon load demand, and the oil light comes on, but it behaves exactly the same as the built in mode in every other way... restarting the engine every time exactly when it should.

    My 12V is much happier now when I have to drive with the headlights on and I expect I'll be able to glide a good bit more during Minnesota's frigid winter months. The downside is more demand on the IMA SoC if I use the AS mode of the switch too much simply because the car must use an IMA start every time. If I trigger the button after a key FAS I can bump start so I'm using a mixture of key and button FAS.

    Is it worth it? That depends upon what you hope to get from installing this modification. For me it definitely is, but probably not for the reasons many would have guessed.

    I owe many thanks to both Randall (highwater) and Mike Dabrowski -- without whom this never would have been done. :) Perhaps this article will inspire others as they have inspired me. After all, this is only the second time I have actually modified wiring in a car!
    Last edited: Oct 5, 2009
  2. iamian

    iamian Well-Known Member

    Excellent write up.
  3. Chuck

    Chuck just the messenger


    That seems like at least 50% of the effort of a MIMA installation!

    My switch is different, but sometimes merely pushing down in the FAS button does not kill the engine - have to release it.

    It will be interesting if the SoC drops a little from long FAS glides, etc....I suspect you will see some of that.

    I second the well-done documentation. :)
  4. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Sean:

    ___Excellent detail and article!!! Insight-I owners everywhere will be thankful for your excellent write-up and pics.

    ___Good Luck

  5. Kacey Green

    Kacey Green Well-Known Member

    What are the concerns with swapping out the 12v? I was trying to decide between yellow and red top. And now you've mentioned a possible issue.
  6. Nevyn

    Nevyn Well-Known Member

    Why can't you bump-start from a button-initiated FAS? To me, it sounds like you're saying you can only bump-start if you key-off to FAS.

  7. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Kacey, Manuel has mentioned it a few times -- I don't know the specifics.

    Nevyn, the engine automatically restarts for you when in Auto Stop mode if you shift gears, touch either the clutch or the gas pedal, or run out of braking vacuum. There is no way to perform a bump start in this mode because the engine will start before you can try -- and it works the same with the button initiated AS mode. ;)

    If I execute a key FAS I can get the DC-DC to come online by pressing the button. If I do any of the things that normally trigger the engine to restart in AS mode after that point the only thing that happens is the DC-DC goes back offline.
  8. Nevyn

    Nevyn Well-Known Member

    Ah, that is information I was not privy to. Interesting...there should be some way to get around that via the CalPod switch, my un(der)informed brain says...but what does it know? It's never driven a manual Insight-I.

    I did get to see a silver Insight-I on my way to work today - gave them a big thumbs up!:woot:
  9. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    The CalPod makes the ECU think that the clutch pedal is pressed continuously -- the FAS mod actually has that included. Since the ECU is also looking at the neutral switch and the accelerator pedal in addition to the clutch, it isn't sufficient.

    That's okay -- it is working as designed and I've got a way around it (key FAS with button press). :)
  10. Gas-x

    Gas-x Well-Known Member

    Youu definately know the ins and outs of your ride! Nice job!
  11. diamondlarry

    diamondlarry Super MPG Man/god :D

    I have an idea for allowing a bump-start with a key initiated FAS. It would require another switch though. Would it work to tap into the neutral switch so that the ECM never sees the car go back into gear?
  12. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I believe you meant a button FAS? If so ye, you could prevent the automatic start if you make sure the neutral signal doesn't change when you put it in gear.
  13. diamondlarry

    diamondlarry Super MPG Man/god :D

    :eek:Yep. Button. If I'm not mistaken, the neutral switch is in the same connector as the injector wires. Is it safe to assume that the neutral switch is a normally closed switch that opens any time the transmission is put into a gear? I may have a project in the very near future.;)
  14. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I don't really know if the signal is high or low in gear -- you'd have to check it. I looked but didn't see the information anywhere obvious online.
  15. john.gerdes

    john.gerdes New Member

    You are a first class genius Sean!

    Very well done and executed.

    Good to know you.

  16. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Hi, John! Nice to see you posting now. :)

    Thanks for the compliment but I'm just standing on the shoulders of giants on this one. :eek:

    Glad you enjoyed the write-up! The system now has that extra wire hooked up with a rocker switch zip tied to the left side of the shifter rod so both the FAS and the clutch hold (CalPod) switches are hidden from view under the shifter boot. Aside from a grid charger install (for maintenance of the hybrid battery) this has been the most useful modification I've performed on the vehicle.
  17. jimepting

    jimepting Well-Known Member

    Hi Sean,

    I'm interested in doing a FAS kit installation on my Silver Insight. I didn't see any mention of where you acquired the kit. Can you elaborate?
  18. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Hi, Jim! I acquired it from Mike Dabrowski (of MIMA fame)... though I purchased his last "pin popping" kit so you'll have to actually splice into wiring rather than extracting and replacing wires from existing plugs the way I did.
  19. jimepting

    jimepting Well-Known Member

    Well, I know how to do that;)

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