FAS switch

[Kacey Green]

Its way too late for me right now, but I wanted to post that I'm working on a FAS switch using some factory wiring and buttons. More details to come.

The method I'm thinking of is either kill the injector power with a relay and the FI fuse, or kill the ground to the existing FI relay.

What I don't know and probably should try out is figuring out how the car will restart after the fuse is reconnected, I'm thinking pull the fuse during an idle (unfortunately it'll have to idle a bit because the fuse in in the under-hood box not the PS or DS boxes.)

I'm hoping that when the fuse is reconnected it will restart automatically, but from what Wayne described about how the HCHI and Insight FAS switches worked, it may require stepping on the gas, or shifting. hopefully this can be done without having to turn the key to get the engine to re-light.

More details and some pics to come. This is Month end and Year End so I'll probably continue to be scarce during the daytime.

I already have the wiring harness and the switch should be in, in the morning.

[msantos]

Hi Kacey;

Good stuff. I hope it will work.

A friend of mine (Paul Scott) had tried that a while ago on his 2006 and was less fortunate. If I recall correctly, it triggered a CEL now and then every time he went for it. I believe he used an automotive solid state relay at the time.

Cheers;

MSantos

[Kacey Green]

The switch came in today. Scheduled for installation Friday.

Did Paul use the powered side or the ground? Which code(s) came out?

How will I re-light the engine? Will it relight on its own or will I need to turn a key. Is there a way to make the IMA re-start the engine or however it turns back on after spinning down but keying back on before the relays have clicked off?

Thanks Manuel

[msantos]

Hi Kacey;

I don't quite recall the full details but after knowing him for a good while and the fact that he picked a multi-gated solid state switch may show he was not playing on the "ground" side. I'll know for sure (along with the raised DTC codes) once he replies to my email.

Cheers;

MSantos

[Kacey Green]

Thank you, I really appreciate that.

[msantos]

Hi Kacey;

Here's the feedback I got:

Paul literally connected the switch downstream from the C101 capacitor. The capacitor connects to a Yel/blk wire derived from pin 24 on connector 24P and downstream from the capacitor you have an orange wire which leads to fuse 7.
He inserted the switch between the fuse and the capacitor and this way he used the "common" to interrupt the injectors.

As I recalled he did indeed have some problems.

The DTC's that were fished out pertained to the "fuel system and readiness". These DTCs would only ocurr before the car reached a good warm up stage. After the engine warms up and closed loop operation is no longer in effect then the fuel system monitoring no longer interferes and you can manipulate the injectors as you see fit.

He also got DTC's relating to misfiring but if I recall correctly, unlike the fuel system the misfire detector will only pause if the counter is not reset by a significant change in throttle amplitude control. So there's a chance that he fell victim to a mis-read.

So what do I surmise out of this? I see a chance of it working provided that we disrupt the injectors only when the engine is out of closed loop. This should be doable as long as we use set the appropriate gauge in SGII and only switch it when close loop ends+a few minutes of warm-up headroom.


Cheers;

MSantos

[Kacey Green]

I'm not following, the car runs open loop when first warmed and when EV or DFCO. The way I'm understanding it now, is to make sure its open loop and at operating temp. Would this be the 120ish deg. F. where it starts allowing Auto stop, or the 150ish where it allows most of the IMA tricks to come online?

So I should set one of the SGs' gauges to show LP and only release (or press depending on how we wire it) the switch when it says open correct?

Did Paul mention if he had to do anything to get the car to re-light? Does it do this when it comes back under closed loop operation?

[Kacey Green]

I just re-read your posts before this post.

What the technician ended up doing was as we discussed earlier, cut the 12v side with the switch.

The switch works technically. When I open the switch in any loop open or closed warmed or not, even IG-ON fresh off acc before starting up, will trigger a CEL. Opening during an auto-stop, open loop, closed loop anything will make clicking sounds in the glove box area and DC-DC cuts, IMA cuts, Brake System light lights, IMA, VSA (not the triangle the letters) and sometimes TPMS light along w/ the CEL.

Startup will happen with the conventional starter if I don't go through ACC first after re-closing the circuit. The VSA, Brake system and IMA lights stay on, of course Assist and Regen are gone, the care drives funny like this, but it also looks like the DC-DC stays off too.

If I open the circuit w/ the car off but in IG-On it will only trip the CEL not the other lights.

CEL can't be cleared by the SG if the car thinks it is on regardless of what's happening with the engine, the screen on the SG goes blank and stays that way until I press the home button, it will still record everything they way it is supposed to. If I turn to acc and then back to IG-On I can clear the codes, when I do clear the codes, if the switch is closed, there is a clicking sound in the glove box area right before the CEL goes out.

I was wondering if a properly sized resistor could be put into the circut when the relay is disconnected would that do anything useful or does the relay itself activate some kind of snesor? Or fearfully, we didn't get just the injectors but the whole injection system ECUs and all.

[Kacey Green]

The car runs normally if I leave the switch closed, like it has been since just before my Detriot trek, through this morning (when it was wedged in my left fender between the headlight assembly and the underhood fuse box.

[msantos]

Hi Kacey...

Sorry to hear about the CEL Hell.

Like many of us have found before, the HCH-II is a royal pain in the neck to hack with simple procedures. So far, its software governance has proven to be very tight with almost no tolerance for even the slightest discrepancy.

A properly sized resistor might do it. I would start with a combination of a fixed resistor (i.e 2.2K) and a variable resistor (4.7K-33K) connected in series with the 2.2K... then once installed I would vary the value after flipping the switch until I see a difference. It may take a few tries and a change of resistors of different values but if I recall the circuitry, you might just get lucky.

Cheers;

MSantos