FTO Drivers Club, Western Australia

[RichardH]

Next week, it's finally time to connect up the Jaycar/Silicon Chip voltage interceptor kit to the FTO's MAP sensor. It can be used to map input voltages to specific output voltage modifications.

The kit is better suited to airflow sensor output (where the voltage output changes as rpm increases). Atmospheric pressure sensors - as used with the MIVEC engine - will apparently output a voltage more in line with throttle position. Not so useful, as it's not possible to differentiate between high rpm and low.

But I have a plan! I've modified the kit to intercept ONLY when MIVEC is active. The engine ECU switches a relay to manage the MIVEC on/off... so I'll be connecting it up to an extra 5V relay inside the Digital Fuel Adjuster. This means any change in MAP sensor output will only take effect from 5500rpm and above. Additionally, I can ensure that ONLY "wide open throttle" voltages are modified. This means the engine management works exactly as standard in all driving situations except full throttle over 5500rpm... the exact scenario when the FTO engine ECU runs things a little rich.

I won't be able to tune around the "very rich" fuelling spikes at MIVEC cutover (the reason for the torque dropoff around 5500rpm), nor the similarly rich behaviour above 7500rpm. But, after talking to a seasoned EFI expert, I have no desire to do so. This rich air/fuel ratio is a safety buffer built in by the factory at the rpm points most at risk when it comes to detonation... the switching from low rpm cams to high, and the upper reaches of the rpm range. So I'll be content to leave the safety margins intact, and simply move the MIVEC torque curve up a hair (or two).

I'll install it early next week, as I have a week off work. Then it's off to Hyperdrive Motorsport's dyno for a bit of tuning and experimenting. It should be interesting to see the results... if any, hehe.

We need to avoid any detonation, as the engine ECU will switch to low quality fuel maps as a defensive measure if the factory knock sensor gets a whiff of it. Apparently, it can take up to 100km of normal driving before it switches back to the "quality" fuel maps again. That will be annoyingly disruptive! So I guess it will be down to the skill and ears of the headphone wearing dyno operator, hehe. Hyperdrive have a good rep, so I guess we'll see what turns out.

Let's hope nothing goes horribly wrong! I have no desire to bugger up a perfectly good MIVEC powerplant...!

Ah, it's all good fun. Gotta do SOMETHING hare-brained during my time off, hehe.

- Rich

[ph3var]

Keep me posted Rich as I wouldnt mind catching up to have a look over this little experiment. I could take a day off next week to give you a hand if need be.

Also what was the product code of this kit as I have a wholesale account with Jaycar.

[RichardH]

Here they are:

Digital Fuel Adjuster: STOCK-CODE: KC5385 - $79.95
Digital Hand Controller: STOCK-CODE: KC5386 - $59.95
Fooling with your FTO while on holiday - priceless

- Rich

[ph3var]

STOCK-CODE: KC5385
RRP: $79.95
Qty 1+ $51.17
Qty 3+ $47.17
Qty 5+ $43.17
Digital Fuel Adjuster

STOCK-CODE: KC5386
RRP: $59.95
Qty 1+ $38.37
Qty 3+ $35.37
Qty 5+ $32.37
Hand Controller for Digital Adjusters

[(vlad)]

Group buy

We should all one weekend do this as a group......maybe wait until Rich blows his car up. lol

[RichardH]

...then find out exactly what I did... and don't do that!!

- Rich

[RichardH]

Okay, the in-car wiring is all done. The voltage interceptor is patched into the MAP sensor output signal.

I've also made the modification to the DFA unit so it only intercepts when MIVEC cams are activated. This was achieved using the engine ECU pinout to the "Engine Control Relay", which is under 1V under normal driving, and 12V when the high-lift cams are used.

Interestingly, I found that the engine control relay is a "normally closed" relay... the opposite to the way I'd expected it to work. [edited 21/7/05 - Nope, that's b*ll*cks - see subsequent post] When the engine ECU signal to the relay is under +1V, the relay output to the MIVEC oil valves is +12V. And when the engine ECU wants MIVEC and switches on the relay, the oil valves are "switched off". I guess they are held closed, then "released" to enable MIVEC. [edited 21/7/05 - b*ll*cks, b*ll*cks, b*ll*cks]

The circuit on the relay side didn't really matter. But what did matter was that the ECU-to-relay voltage behaved unexpectedly when the ignition switch was totally off. Instead of an open circuit (as it is when at idle), it was a full +12V. I wasn't happy with the thought of the engine ECU keeping the DFA "intercept/bypass" relay powered whenever the car was parked up, so I added a separate relay that only connected the MIVEC switch-in wire when the system was actually running.

That's basically all in and working now. I still need to do an actual driving test of the interception, to ensure it really does kick in as MIVEC engages. That'll have to wait until tomorrow!!

Dyno's booked on Friday, and at this rate the whole system will be 100% ready well before then.

- Rich

[RichardH]

Okay, here's where I'm at with this project. Let's start with what I've learnt...

(1) If a hobby scalpel blade is too blunt to cut you, it's too blunt to strip electrical wires.

(2) If a different hobby scalpel blade is so sharp that it featured in "Kill Bill Volume I", it will happily strip electrical wires. Unless you give it to me. If you give it to me, I will re-enact the aforementioned movie using my right index finger as a stunt double for Lucy Liu. Apologies if my keybpard work is a bit ionaccurate right now,.

(3) Buy a set of proper wire strippers, for God's sake.


Now for the serious stuff...

(4) The FTO's "Engine Control Relay" (located low in the centre console, near the firewall) is nothing more than a dumb "engine running/engine not running" relay. It does NOT do anything directly related to MIVEC cutover... it simply supplies the constant +12V to the MIVEC oil valve solenoids when the engine is on.

(5) The actuation of the MIVEC oil control valve solenoids (that switch high-lift cams in) is performed separately by engine ECU connector B-33 pins 34 (blue with yellow stripe - right bank) and 35 (blue with black stripe - left bank). These pins don't provide +12V to the oil control valve solenoids... They pull the two circuits to EARTH.

It was quite a steep learning curve trying to put all the pieces together!

I wired up the interceptor for a test drive today, with zero mappings for MAP sensor voltage. In theory, it should have switched in at 5500rpm, but done absolutely nothing. I wish!

What I didn't know was that the original interception "switch in/out" relay had failed. When enabled, it was no longer supplying any output signal. Easy to find with a multimeter, but more exciting to find during a test drive.

As the revs hit 5500rpm, MIVEC kicked in. So did my interceptor. And it proceeded to tell the engine ECU that this particular FTO was floating in the endless vacuum of space, with a manifold absolute pressure of zero kPa. Not surprisingly, the ECU threw up its hands and piked out altogether. It was the most violent throttle off I've ever encountered!

So the unit came out (easily removed, as I've used DIN plugs when wiring everything up), and I was off to buy a replacement relay.

When I replace it, I will be able to rework the pcb setup slightly, to take advantage of the stuff wot I've learned this morning. It's going to end up pretty polished - once it works!

Last week's dyno session was a non-event also, as Hyperdrive had a problem job overrunning. I got there nice and early, but was told I could either wait around for an hour or two, or reschedule. It was good in a way, as the unit definitely needs more work to get it doing what I want it to do.

So maybe next week!...

- Rich

[Guest]

hey richard, howd this end up going?
i noticed in the other topic you mentioned you werent working on this anymore

[RichardH]

No, it's still a goer, but I just haven't had the time! A 3yo in the house makes it hard to ever have a soldering iron out. Our house ain't massive, so I don't have a dedicated room for "blokey stuff", hehe.

The project is tantalisingly close, but needs a final tweak or two. The relay still needs to be wired up to the MIVEC cutover at the ECU... I had a number of false starts, but know exactly what goes where now.

I also want a sodding LED that tells me when MIVEC/interception is ON.

There's another minor bit of rewiring inside the unit too... just to ensure the smoothest possible cutover.

Once that's done, and working properly, I can think about getting it tuned. Sigh....

- Rich

[Guest]

well you could hook the cross over light to the original seatbelt light,
buckle up!

[RichardH]

hehe. I don't need it on the dash... just something... *something*... on the damn unit that tells me if it's switching over and being useful!

In fact, I did have an indication of interception switching on during the previous test drive - the complete and total cessation of all fuelling! But that was a bit too violent. I'd prefer, like, maybe a little green LED instead.

- Rich

[(astroboi)]

hey thats a good idea i never thought of....
actually never put much thought into it in the first place...haha

it would be a good thing to have, an LED to turn on in the dash somewhere to tell me that the mivec kicks in...isit hard to wire it up to make it all happen? if not, it will def "rice" up the car a bit...haha....just makes it more fun when i am gunning it to realise that the mivec is actually on...lol

interested...

[RichardH]

Well, I've worked out the ECU pins required. A 12 volt LED and you're sorted.

- Rich

[(astroboi)]

so r u gonna make up a quick DIY?

or else can u show me how to do it one day while u are doing yours too...
maybe we can meet up one day and do it together...

tommy