I'm not sure about that one because it has never happened but yes what you said does seem to be the case. I'll try it later.

 

This thread has been really helpful, thanks folks. I am really glad I made the switch from edmunds to this forum.

Here is a summary of what I have come away with:

I was confused and thought that assist pressure and brake pressure were the same thing.

Either the assist or the mechanical backup can produce brake pressure to the calipers.

ABS bleeds brake pressure from the calipers not the assist. The ABS pump cannot repressurize the assist either, as it can only restore fluid/pressure lost during the ABS process. Therefore it does act to preserve whatever level of assist you have because it keeps you from having to further depress the pedal to restore brake fluid drained off by the ABS system. Another way of describing it is that ABS is a circulatory system, it bleeds pressure from the calipers and then pumps it right back into the master cylinder, thus keeping the main brake pressure constant.

My misconception was I thought the assist pump was used to restore fluid drained by the ABS, I did not know about the electric pump that is part of all ABS systems.

Other people who have observed that the act of depressing the pedal (as opposed to holding it) is what loses assist pressure are right on.

Therefore one can use ABS with or without assist pressure. The ABS warning light does not come on during an FAS either, so it thinks it is ok too. Thus depressing and holding the brake pedal during an FAS (even to the point of activating ABS) is an efficient and safe use of pressure, unlike pumping.

Here is a choice quote from an ABS article:

"ABS can only reduce pressure, therefore brake pressure can never be more than what the brake pedal allows".

I for one am not strong enough to activate the ABS without assist (unlike psyshakennegger, whom I respect and admire but don't have his leg strength, although I reject insinuations impugning my masculinity :-) ).

So I will now happily FAS, even at freeway speeds, but be careful to keep my brake pressure up by starting the engine anytime I release (not depress) the brake pedal.

Note: In case it is not clear, yes ABS will function with or without assist pressure if I understand things correctly and your leg is strong enough. I am looking forward to lakedude trying it.

 

Kurt, you and I agree about how all this brake stuff works. I pumped the brakes till the vacuum assist was gone and then tried to slam on the brakes hard enough to kick on the ABS but I didn't have the legs for it either. Last night I tried the Vette, I might try again in the Civic using both feet. Stopping cars without assist is not fun.

 

That's what I thought, it will be too hard to engage the ABS if all assist is gone. The only way it will come on is if the surface is slippery... like loose dirt on pavement or snow.

 

I can't imagine too many instances where people will be using a fas and riding the brake and then need to slam the brakes for an emergency. I guess the key is that if you bleeding the brakes by pumping them you should probably restart the car to get the resevoir filled.

 

....and keep foot #2 ready.
I hope nobody's doing this in heavy traffic or high speed.
Safety #1

 

And as Tom indicated, perhaps your Right Hand on the emergency brake lever to activate your rear brake(s). I assume the emergency brake actuates both rear brakes.

This has been an interesting thread. I think it would be cool if Honda put a button on your steering wheel that would engage a FAS. It would "kill" the engine, but then bring you right back to II on your ignition. Then whenever you hit the brake pedal, the computer would somehow disengage your CVT, restart the engine, reengage the CVT, and you'd be back to normal. Sort of a reverse of what happens during an auto stop where releasing the brake pedal starts the engine.

I can visualize this process in my mind, and I'm sure it could be designed. I suppose it could be set up to happen automatically whenever you take your foot off the accelerator for more than say 5 seconds. The car would put itself into FAS, and then reengage ICE if you hit the brakes while traveling at speed.

Does this make sense?

Mike

 

yeup... all the systems are there... take the cruise control option and reverse it, brake is pressed, cruise control goes off... so there are system that go off when an brake event occurs. in this case we want to start the car. and since cruise only works at above 25mph (i don't know the exact number) you could use the same limit.

 

I posted this bit in a thread about reboots a while back, but I thought it might be worth bringing up again...

HCH CVT Semi-forced autostop:

My understanding of the 2004 HCH is that the computer has a few things it looks for before it will perform an autostop. Engine temp has to be in the normal range, there has to be adequate vacuum pressure, IMA battery levels, the mph of the car has to rise past 10 mph and then fall below it again (for the CVT), and the brake has to be depressed (for the CVT). (there may also be an angle sensor involved as well, but I haven't experienced it enough to be certain)

My idea for a semi-forced autostop for the CVT HCH:
two switches
one momentary, the other a toggle with an annoying blinking led.

The toggle switch would be connected to the same wires as the brake light switch on the pedal, making the computer think I'm riding the brake but without putting any pressure or depleting vacuum. The annoying blinking led would remind me that it was on because my brake lamps will remain lit during this CVT forced autostop.

The momentary switch would be connected to the tach from the wheels and would serve as a momentary disconnect causing the computer to think that the car is moving slower than 10 mph for a brief moment.

By flipping the brake switch on and then hitting the tach momentary switch, I think it would satisfy the computer's requirements for an autostop.

This would seem to give me full control of the CVT HCH, the 12v would still be connected to the 144v IMA, and I'd have the ability to come out of autostop in an emergency by pressing the brake or by pressing on the gas like normal. When I'm done with the semi-forced autostop, I flip the brake switch to off and it takes the car back out of autostop. (The annoying blinking LED is to remind me that my brake lights are on in case I come out of autostop by any other means)

Any other thoughts or parts I missed?

Also, has anyone with a CVT HCH been in an actual autostop (not FAS) and coasted down a large enough hill to reach higher speeds (40+) and before coming out of it? How do the engine and transmission react?