Clubjazz - Honda Jazz & HR-V Forums
Honda Jazz Forums => Honda Jazz Mk2 2008-2015 => Topic started by: lexi on December 03, 2014, 08:46:40 PM
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Have been thinking of the scenarios of this box. Sitting at lights with foot on brake and in A1.
Am I right in thinking that we are in gear but de- clutched? If so, are we not putting pressure on release bearing? Any thoughts here?
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Can you let me know what you are hoping to find out? (I have an iShift so I am keen to know as much about them as possible).
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Very little online about the actual workings of the box. If you have a manual box and are sitting at lights, in gear but with clutch down, that is bad practice. You are stressing release bearing. I want to know how the iShift does the same thing with the hydraulic robot........without stressing the bearing.
It is not something that has reared it's head as a problem AFAIK but many owners have different practices.
Proper modern auto boxes have sensors that de-clutch when you sit at lights with foot on brake. The de- clutching in this instance obviously involves no release bearings as the clutch pack is disengaged by solenoid.
I want to know if we still have standard clutch fork and release bearing on our iShift and what the robot does at the lights with foot on brake.
My car is also 10 plate.
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I would note that with my Jazz Hybrid (CVT gearbox) I need to leave the car in gear with my foot on the brake in order for the engine's auto stop-start to work. If I shift the gearstick to N (still with foot on brake) then the engine immediately wakes up. So, if that system was designed around the driver keeping the car in gear at the traffic lights then it may indicate that Honda assume a similar driving style for the iShift.
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Thanks John. Interesting with the CVT.
Different animal mind you and our i Shift are manual boxes with a clutch.
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http://hondafitjazz.com/manual3/en/html_en/000000000001359.html (http://hondafitjazz.com/manual3/en/html_en/000000000001359.html)
If you follow the assembly drawings on this page and the associates links further down the page there are some references and pictures of the fork and release bearing. Certainly how to install the clutch actuator on an iShift. You might be able to get an idea of what's what?
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I think the wiki section on the Civinfo forum has tech details on the I-SHIFT.
Sent from my GT-S7500 using Tapatalk 2
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Thanks for info. Further to this thread;http://clubjazz.org/forum/index.php?topic=6451.0 (http://clubjazz.org/forum/index.php?topic=6451.0)
The research I have done indicates that my first assumption of using the handbrake may be correct procedure?
Use the hand brake and leave in gear and foot off pedals. Someone with high mileage Jazz has informed me that is the procedure.........rather than sit in gear with foot on brake. Would be good to get a consensus on the proper Honda way as a kind of reference for the forum.
Thoughts and discussion are welcome.
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I don't recommend this. My other half was waiting to pick me up from Hospital a while ago. She forgot the engine was still running, (It is very smooth and quiet). when she shuffled to make herself comfortable, she managed to catch the accelerator and the car lurched forward and touched the vehicle in front. Luckily only a cracked number plate. Could have been worse or even a person walking in front. Of course, when you are in traffic it is less likely that you would forget the engine was running.
Use the hand brake and leave in gear and foot off pedals.
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Did that happen with her handbrake fully on? I read elsewhere that once handbrake light is on,the clutch is disengaged? I will try this myself. ATM I am simply putting into neutral if more than a minute at lights.
The handbrake on, and foot off the pedals is what a Jazz owner uses who has put 110k miles on a Jazz from new. I am still gathering evidence here having read the Civic forum.
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Yes, handbrake fully on. Obviously a small number of revs wouldn't do too much but a fair number of revs and no handbrake would hold, even possibly dragging the locked rear wheels.
Handbrake on may disengage the clutch at tickover but it does not at higher revs.
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I am certain that the handbrake does not dis-engage the clutch, especially when reving.
I encounter several steep hills with traffic lights where I have to do a handbrake release while bringing the revs up.
The hill start mechanism (p303 in the manual) operates while the car is in gear only (not Neutral).
The brake servo maintains some pressure on the brakes for about 1 second to allow you to get the revs up. However on a steep hill it is not enough to stop it rolling back - so thats where I need to use the hand brake.
When you rev in gear with the hand brake on - the car hunkers down indicating that the clutch is engaging.
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Handbrake on may disengage the clutch at tickover but it does not at higher revs.
Yes, this is key. I would like to see the drawing of handbrake sensor activation and what it is doing.
As you say App. It is the revs that picks the clutch up and drives car forward. All ECU and engine speed sensor/servo controlled. Good info guys in understanding the unit and making it last.
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Been reading a bit about 'normal auto gearboxes' with a torque converter link between engine and gearbox, seems there is no clutch and the torque converter is still trying to drive the car even at tickover, but cannot put enough power through to move the car, as the revs rise the power transmitted goes up and if the brakes are off the car will move, but if the brakes are on and you increase the engine revs the converter will try to drive against the brakes, and the excess energy is lost as heat into the gearbox fluid. It seems that the torque converter never really removes drive power from the gearbox, and maybe the i-Shift has a torque converter which works like this, and has the ability to do a hill start because the system has devices to stop the car going backwards and will increase the revs to stop car rolling back. The fluid link between engine and gearbox means that when you put lever to 'park' position there is a mechanical lock applied to the output shaft of gearbox, which is why you should never select 'P' while car is still moving as this can shear the lock mechanism and/or damage the gearbox. It is recommended that with an auto box you should select neutral or park when standing still in traffic for longer times because it disconnects the torque converter, unloads the engine and the car uses less fuel.
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and maybe the i-Shift has a torque converter which works like this.
And maybe it doesn't have a torque converter? As far as I can see, it just like a manual gearbox with a conventional single dry plate clutch. Compared to a normal manual the only thing that is different is a computer and actuators are doing all the donkey work.
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Yes Eddie, I am leaning towards what you say. I think basically there are two actuators. Clutch and gearchange. Switches on the 2 brakes will trigger de-clutching. Once lever is manually moved into drive the actuators can do the 6 forward gears. Neutral and reverse can only be obtained by operator, manually. The Volkswagen robot boxes have more stages and complication. Our iShift and the Citroen Sensodrive are similar ilk.
Your premise on the true auto box is correct Culzean, but with a few additions. Same as above with only being able to select neutral, drive and reverse manually. However the last 2 generations of autobox from Aisin (Toyota) have the following feature. When in drive and at a stop with footbrake applied, the ECU will de -clutch the transmission after 30 seconds. This is to avoid the issues you mention and is a safety device.
I am thinking the iShift does similar with it's clutch actuator. It still leaves me thinking that the true clutch fork has the pressure on release bearing, so I am going into neutral , till I find out otherwise.
The true auto box (epicyclic) still has clutches. They are inside the torque converter. When converter fails the clutches have worn and overheated. They slice the flat cylinder like opening a roll. Replace the clutch packs, then weld it back together on a precise machine for the purpose. This is why it is serious money.
A buddy of mine who has stripped these proper auto boxes down, still maintains they are easier to work on than manual boxes. Also, proper auto boxes are much stronger for big horsepower. The "sealed for life" concept has killed lots though. 40k oil changes on the real autos for me. No fails yet.
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The true auto box (epicyclic) still has clutches. They are inside the torque converter.
Not the case (usually). For instance the forward and reverse clutches of the Borg-Warner 35 are inside the main box and are wet multiplate type as you described. The torque converter stator has a one-way clutch which is more of a roller type type arrangement that allows solid movement in one direction and slippage in the other.
In ye very olden days these autos could be tow started (as could the early Mini/1100 4 speed AE boxes) as they either had a secondary oil pump on the output or the main pump on the output shaft so pressure could still be built up in the hydraulics without the engine turning.
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That is what I meant by clutches.........wet multi-plate clutch packs.
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Yes, but you said they were inside the torque converter and not inside the gearbox??
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I have been interested to resolve the -assumption- for want of a better word, that the handbrake disengages the clutch so I called Hendy Honda technical service department in Exeter 01392 423 800- this is their response:-
The hand brake does NOT disengage the clutch (aka the Parking brake as referred to in the manual).
Sitting at zero MPH or at low revs makes no difference.
I actually went and tested that out - it has a 'creep' function at low revs and I think this allows one to think the clutch is disengaged, where as it is at least partially engaged or being made to slip by the ECU.
On his advice a momentary hand brake start on a hill is acceptable, but do not sit at idle in gear with the hand brake on UNLESS you have your foot firmly on the foot brake as well.
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This shows the clutches inside TC https://www.youtube.com/watch?v=vk3n_ss0x5s (https://www.youtube.com/watch?v=vk3n_ss0x5s)
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Good stuff APP. Handbrake is a misnomer then. I think from the info here it is plain and simple to make a choice for the best.
My routine will be set now .
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Yes, but you said they were inside the torque converter and not inside the gearbox??
My bad on poor wording Eddie. The clutches that lock transmission through the gears are in there. What I was getting at really, is that the TC is the key component of the box as it does so much and also that there are clutches in there. Without lock up clutch you have low gears and high revs, so terrible economy.
I fitted a switch on my old Nissan Patrol that enabled me to lock up 2nd third and fourth for more flexible driving. Modern autos do all this by better design.
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That video link has enlightened me to the "modern" practice of adding a lock-up clutch to the TC (in additon to the two or so inside the box).
Interesting that the ishift has a creep clutch burner function.
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I wont be letting mine creep much Eddie . It will be into gear and away. Sounds like a dragging clutch function that creep thing. ;D
An interesting thing that crops up is that the actuators on Honda system (probably others too) are made by Bosch. Seemingly Honda dealers were instructed to change actuators when Civics were stuck in reverse. It seems that the actuators needed separating and then system reprogramming. Honda dealers were simply replacing actuators at 1300 quid I think.
The Citroen system has been doing similar things, so I think they would be replacing as well.
It does seem that out of most Techs in a dealership, you are lucky to get one who knows the score. I suppose they have no need to know, or desire to know.
I think The Jazz in UK has had upgrades on software with iShift as well as other things improved. Not many failures with it.
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I called a Honda employee that I know when I first got interested in each of the Hondas I have bought.
On the iShift he said that they had ironed all the initial problems out and it is very reliable.
So it is a bit of bargain against the rest of the range (if you can put up with / learn to deal the jerking gear changes) as the press warns people off them which is good for price and availability second hand.
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I was and still am a little in awe? of the I shift. I stated in a previous post, I had changed the air filter, since when I have found the I shift a little more amenable, especially changing between 1st and 2nd.
Having driven conventional automatics for over 10 yrs, I am trying to get into the habit of foot off footbrake and handbrake on when stopped at lights etc, leaving it in gear. As far as I can make out, reading the info in the manual etc, providing the engine is not running above tickover, the clutch is disengaged. I like most, wonder about the 'clutch release bearing but conventional stick shift cars seem to cope with people sitting with their foot on the clutch, in gear at lights etc.
I am mindful, that when sitting still for any length of time, an auto box should be put into N or P as the torque converter will overheat. The I shift doesn't have a torque converter, so presumably the clever little men at Honda have set the system up, so that when stopped, with the engine on tickover, the clutch is disengaged. SO back to the clutch release bearing, I suppose you pays yer money and takes your chance.
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As I mentioned , a chap has a blog on Jazz . His method with stop and handbrake on, is same as yours. 110k miles from new......no issues. There are never any issues with a release bearing........till gearbox has to come out of course to replace it. :D
The good news for us is that I can find no mention of a problem with that bearing from any owner.
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Very interesting reading what you said.
I have been outside my house for the last 15 minutes testing that out with the hand break in a1 and R.
There -must- be a sensor relating to handbrake position (on) at idle. (Which is at odds with what I was told by Hendy Honda).
I orientated the car first pointing up a very slight incline allowing it to roll back very slowly with the hand brake lifted to the first notch at tick over in a1. As soon as you drop the hand brake it creeps forward - indicating that the clutch was disengaged until I dropped the hand brake.
Same happens in reverse.
As soon as you increase revs clutch engages with handbrake on.
Ill get one of the service people at Hendy to tell me what they think happens when I take the car for a service and enlighten them with a demo!
I was and still am a little in awe? of the I shift. I stated in a previous post, I had changed the air filter, since when I have found the I shift a little more amenable, especially changing between 1st and 2nd.
Having driven conventional automatics for over 10 yrs, I am trying to get into the habit of foot off footbrake and handbrake on when stopped at lights etc, leaving it in gear. As far as I can make out, reading the info in the manual etc, providing the engine is not running above tickover, the clutch is disengaged. I like most, wonder about the 'clutch release bearing but conventional stick shift cars seem to cope with people sitting with their foot on the clutch, in gear at lights etc.
I am mindful, that when sitting still for any length of time, an auto box should be put into N or P as the torque converter will overheat. The I shift doesn't have a torque converter, so presumably the clever little men at Honda have set the system up, so that when stopped, with the engine on tickover, the clutch is disengaged. SO back to the clutch release bearing, I suppose you pays yer money and takes your chance.
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As soon as you drop the hand brake it creeps forward - indicating that the clutch was disengaged until I dropped the hand brake.
Same happens in reverse.
As soon as you increase revs clutch engages with handbrake on.
I think that what this indicates is that at engine idle the handbrake is capable of holding the car stationary even though the clutch is lightly engaged.
As you increase revs the clutch bites more and overcomes the handbrake.
The only way to totally disengage the clutch is to put the car in neutral which exactly the same as the way the CVT operates.
Vic.
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Well - I put the car pointing both up hill and then down hill. The hand brake on first notch will not hold the vehicle at a 'stop' at idle revs. It will roll down hill.
This observation suggests that at idle with the hand brake engaged at notch 1 - the clutch is either fully disengaged or sufficiently disengaged as to be ineffectual on a less than 2% slope. The hand brake wire is not over stretched.
Remove the hand brake and the car moved in the selected gear direction, against the effects of gravity.
I was surprised about that to be honest.
Until someone gets a correct and accurate answer out of Honda we can surmise all we want:)
As soon as you drop the hand brake it creeps forward - indicating that the clutch was disengaged until I dropped the hand brake.
Same happens in reverse.
As soon as you increase revs clutch engages with handbrake on.
I think that what this indicates is that at engine idle the handbrake is capable of holding the car stationary even though the clutch is lightly engaged.
As you increase revs the clutch bites more and overcomes the handbrake.
The only way to totally disengage the clutch is to put the car in neutral which exactly the same as the way the CVT operates.
Vic.
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I decided to read the book of words. ie the 400 plus page Honda instruction book;
Not word for word but, it just says pull up in what ever gear you are in. Foot off accelerator and onto brake. Before moving off make sure you are in the correct gear.
It also says DO NOT HOLD THE CAR BY USE OF THE ACCELERATOR.
That's what Mr Honda says
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I would say that it is poor practice to stop, at a junction or lights etc., in gear with foot brake. I would suggest that, unless you expect to be held up only momentarily, when you roll to a stop you should apply hand brake and shift into neutral. This will reduce wear on gears, clutch ( as it drags and heats up etc), fuel ( as the dragging clutch causes engine to call for more fuel to keeps revs 'up' ) and stress to normal hydraulic brake system. Also not blinding people behind you with all them 21 Watt brake lights illuminated ( I know they are LED's, but are equivalent to 21Watt ). By the way it is probably wise to 'nip up' your hand brake adjustment so that is capable of holding the Jazz in first gear at tick over speed on first or second notch / click. Remove your centre console around your hand brake, jack up a rear wheel and with a 10 spanner do up the slack until the wheel just starts to bind. Then swap the jack to other rear wheel to compare. maybe take for a little test before you put the console back. Tools are 8mm socket ( cross head if your strong enough for rea cup holder hidden screw ), medium blade screwdriver, trim tool ( to remove trim under hand brake lever ) and 10mm spanner.
The car can pull off with hand brake on.
I have had a Jazz EX (1.4) I-shift for 1 week now and am liking the semi automatic. I have giving it new filters and engine and gearbox oil ( MTF 3). Sweet as a nut! As they say.
Just my opinion about waiting in Neutral with handbrake on ( similar to normal motorbikes with sequential gears and clutch ) I hope I don't offend with my tips. If you are not moving put it in Neutral! :D
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The car is under a full service arrangement and extended warranty. If anything needs doing it will get done under that contract:) Thanks for the comment.
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The point about testing the clutch action relates to the fact that the ECU monitors engine revs and handbrake position as well as foot brake.
Each of these factors helps it decide whether to engage or disengage the clutch, and when to release the brakes under hill assist.