FAS with CVT Insight?

[Mike Dabrowski 2000]

I got a call today asking if the FAS system will work on a CVT Insight.
http://www.99mpg.com/Data/resources/dow ... al_fas.pdf
The CVT has no clutch and neutral switches, so of course that would not be required.
Has anyone tried FAS on a CVT, using a simple injector cut switch? I am sure the engine will stop, but what I don't know is will it stay off and will it restart like the 5 speed

[ikhoudvanu199]

i have no idea about that

but i noticed in the picture at the top of your homepage...theres that shot of the insight dashboard...but the asst and chrg displays are backwards, like, in the wrong places...

[Mike Dabrowski 2000]

I never noticed the reversed display? I was not the one that generated that upper photo, so I can't say where he got that ?
Boy you must have good eyes to catch that one, you get the "most observant webpage viewer"

[ikhoudvanu199]

haha...yay! now, back on topic...anyone know anything about FAS in a CVT?

[gpsman1]

Originally Posted by ikhoudvanu199

but i noticed in the picture at the top of your homepage...theres that shot of the insight dashboard...but the asst and chrg displays are backwards, like, in the wrong places...

Wow... he's right... it's bass ackwards compared to my 2000.

I wonder if different markets have different dashboards?
Do any cars in Europe have the steering wheel on the right?

Sorry to be OT but I like interesting finds like that. It sure looks like a photo, but is it an artist's graphic by chance?

Hey! On closer look, I answered my own question! The steering wheel IS on the wrong side too!

[joecvt]

I tried a few things today in my CVT...It was pretty darn windy out there!...Anyway, I always wanted to check out that signal called the heater standby signal that gets sent from the climate control to the ECM. I hooked up a wire to pin 10 Brown/Yellow in connector C531 (under the dash. Changing the volt meter to show duty cycle it shows:

20% when engine is still warming up OR when AUTO mode is on (without economy mode enabled)

40% when engine is warmed up AND economy mode is enabled

60% when climate control is turned off

AutoStop will not happen at 20% ... Vehicle speed did not change any percentages so the climate control is not the main decision maker for AS (as I once thought awhile back)...It still confuses me how the climate control uses the VSS signal....Oh well....

The next approach I did was to monitor the fuel cut off relay that turns off the fuel pump. I attached a wire in pin 2 of connector C501 Black/Yellow. That wire is the voltage activated by the relay to power the fuel pump. While driving, if you let your foot off the gas completely (even without touching the brakes) the relay will open disabling the fuel pump within ~2 seconds and stay that way until press on the gas again. So no fuel is being used while coasting down a long hill or when comming to a stop while the transmission is in "drive".

The next thing I did was attach a wire to A15 of the ECM Green/Yellow...This is the wire that turns the relay on or off by providing ground to the relay (enabling voltage to the fuel pump) when fuel is needed. It is also interesting that the immobilization system within the ECM uses this same wire to disable startup by not providing ground to the relay...(Providing your own ground to A15 could probably then bypass this setup but that is another story)

So I thought if I could interupt this ground signal to cut off the fuel at will, why not try this method. I didn't want to cut any wires so I took the fuel cut relay out and just extended wires into the 3 connectors that would not be bypassed. I then attached a wire directly to the relay and brought the wire back into the car so I could manually ground it when I wanted.

Sure enough, without grounding it, the car would crank over but didn't start due to no fuel...I then grounded it and drove around the neighborhood. I first made sure the car would go into normal AutoStop and it did....Then when starting to coast to the next stop with my foot on the brake, I removed the ground and the slow down acted normally (still foot on the brake). When it got to about 4 MPH, the RPMS went to zero and the idle stop light was blinking. But I really didn't do anything special because that is exactly what it would have done anyway. I attached the ground wire again and took my foot off the brake and the car started up as normal.

My next test was to do the same test except put the A/C on so it normally wouldn't go into AutoStop when coming to a stop. So I did the same as above but when it got down to about the 4 MPH, there was no sudden cut off. Instead it kept on going down to 0 MPH showing a stall (no fuel)...Within about a second, the IMA motor automatically kicked in to try to start it up again. It does this a couple of cycles and I'm not sure if it would have eventually given up trying but I did not want to push the limits. I connected the ground and it started up....This was all with my foot on the brake so it seems like something else would have to be bypassed in order to insure no restart attempts every second or so.

I have never had my car stall like that so it was pretty cool that the IMA will try to restart when it wasn't planned....

I also thought that there could be other complications here because nothing told the TCM (CVT control module) to disengage the forward clutch at ~4 MPH like in a normal auto stop....That created a strange sensation.

So it seems like you need a method to stop the engine, a method to stop the engine start retries, a method to inform the TCM to disengage the clutch...

I looked over the entire FAS thread in this forum (that is long thread)...If I were to try just cutting off the ignition coils (as Calpod first did), I think that there would still be the three problems to overcome just mentioned above.

Also, as noted before, the fuel cut off really does work. I do like that that has been verified. It seems the only benefit if someone got this to work would be going downhill in neutral and saving the amount of gas to idle the engine (but there would be no regen either).

I don't really want to use a FAS at speeds above 10 MPH...I just don't like that when you come out of auto stop, you have to get going at least 8 MPH before you will go into auto stop again (usually).

This seems to me that it would be a little more complicated to get it working properly on a CVT model.

JoeCVT = Just you average CVT owner

[Mike Dabrowski 2000]

Really nice report joecvt,
I remember that you felt that this climate control signal may have been one of the key signals in AS.It is interesting that it is a proportional PWM pulse , like CMDPWR and MAMODE 1.
The guy that called was more interested in using FAS to cut the engine at lights, when AS did not work.
On the immobilizer, not only is the fuel cut, but the spark and injector activation is stopped as well. I remember trying to get the CVT Insight on a stand running without the key. I finally brought the whole thing to a honda dealer to have a new key code programmed in.
I guess that the CVT is not a good candidate for a simple FAS system, at least not without some more reverse engineering.
Hopefully I will get my CVT on a stand fully functional soon, and we can play some more. The system will have test points on all key signals, so we may be able to dig a bit deeper to simulate hill climbing or running down hills.

[joecvt]

Hi Mike,

I don't know how it was in CT but the winds where terrible in NH yesterday...

Yeah, I was really hoping that I could get a signal from the climate control that once the car moves 8 MPH again, that it would send that signal to the ECM indicating that it is ok for another AS...Oh well, I proved my own theory wrong...It looks like ECM is really the main control unit for AS and it just takes input from the climate control unit and also informs the climate control that it has performed an AS so it can turn the fans off while the engine is stopped (based on climate control settings)

From looking through the manuals yesterday, another strange thing I found that I forgot to mention is that there are two switches on the brake pedal. One for normal brake functions and the other is an Idle stop switch. The strange part is that both go back to the ECM...Why are two needed (unless one is adjusted differently based on pedal movement)?

I remember reading in the manual awhile back that there are two lines of communication back and forth for the TCM and ECM...I just checked today and they are called:

TMA - Data communication line - Engine control data input from the ECM
TMB - Data communication line - Transmission control data output to the ECM

Both are described as pulsing signals. TMA is a grey wire on pin B7 and TMB is a Pink wire on pin B6 of the TCM connector.

I would guess that the ECM will somehow tell the TCM that it will perform on autostop so the TCM knows to disengage the forward or start clutch.

Just like everyone looking at FAS...I wish there was just one wire somewhere that you could tap into to make it all happen like a normal AS.

I agree with the guy wanting FAS at just the lights and heavy traffic...When there is a lot of stop and go traffic, I find myself leaving a gap in front of me or taking off a little later than normal so I can get the car up to 8 MPH just so AS will work again. But that method wastes more gas starting out that way and probably makes others think "what is this clown doing?"...A FAS would be great in that situation.

Even if we somehow solve the problem of the car wanting to restart itself every few seconds, I have a fear of long term damage to the CVT if that part is not resolved. I think most CVT drivers know that normal feeling of how your are coming to a stop and all of a sudden at ~4 MPH when the transmission "lets go" and you coast to the rest of the stop like the car is in neutral. I think that is the start clutch or the forward clutch disengaging to create that feeling. The experiment I tried yesterday when the AC was on and just cutting the fuel made the car coast slowly to the stop without that letting go feeling. I guess the hydraulic pressure loss would make the clutch disengage eventually but would there be any long term damge from doing it that way over thousands of miles?

I may try to access TMA and TMB later on today to see if anything seems unique in the signals for autostop.

JoeCVT = Just your average CVT owner

[Mike Dabrowski 2000]

Joecvt
Yep it was pretty windy yesterday, and cold to boot.
You should come down once it warms up a bit, and I start the Saturday workshops, we can get that CVT on a stand running, and connect the signal breakout box to all of the key signals. I have run it several times, but the rpm keeps reving and slowing down, and it seems to be related to vacuum leaks in the intake manifold.
The intake manifold was smashed pretty bad, and I am too cheap to buy a new one, so there are some leaks that still need patching. I want to set it up with a single drive shaft that will drive a motor generator so I can simulate hill climbing and down hill to get the IMA to work.
I share your concerns about possible damage to the CVT if FAS is not correctly done.

[joecvt]

Mike, Thanks for the invite. I would like to drive down there one Saturday and see first hand what youv'e been up to Earlier today, I took a look at TMA and TMB signal wires at the TCM. The TMA wire made a bit more sense than TMB.

66% on power up (without the engine running)
71% during idle
71% while driving without much engine load (normal cruising)
73% when driving with more engine load (even with assist)
66% when decelerating (with or without the foot on the brake)
66% when coming to a stop with A/C on (so the enigne will idle 71%)
66% during auto stop

I never saw it go below 66% and the highest I saw was 75% for a split second. I didn't see any percentage that would indicate an AS is soon approaching.

The TMB percentage jumped between 81% to 83% and was not predictable. It seems to be a different type of communication. The climate control readings yesterday were very clearly defined compared to today's go around.

Perhaps one way to do this would be to simulate what I do in traffic. We already have a wire from the ECM called ENGRDY (pin A2 engine ready signal) that is 12V when the engine is running and less than 1V when in AS. What if we had a circuit (powered by ENGRDY) that would generate 0v and 5V pulses to match the specs of what 9MPH would be like on the VSS wire. The VSS signal going to the ECM would be swapped (just for a few seconds) with this signal to simulate that the car has gone over 8MPH. The relay that would switch the VSS would only operate for about 2 seconds (each time ENGRDY supplies 12V) then shut off and default back to the real VSS signal back to the ECM.

If this works we would only be cutting the VSS wire near the ECM and tapping into the ENGRDY wire. I'm not sure if the ECM is "smart enough" to want the circuit to ramp up the speed from 0-9MPH within a few seconds or if just dumping 9MPH will do.

I believe this may be able to trick the ECM into AS each time in traffic without the driver having to do anything differently than a normal AS.

JoeCVT = Just your average CVT owner