Author Topic: Cruise Control and its ability to control speed downwards  (Read 6294 times)

guest5079

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Cruise Control and its ability to control speed downwards
« on: January 24, 2017, 02:26:57 PM »
This only applies to our I shift EX, I can only surmise all I shifts with cruise control, will be the same. CVT might have the same software but of course it would not work on a manual.
I raised the point of speed control by cruise control either by braking or engine/gearbox. The general opinion was that although cruise control maintained speed on the level or uphill, it did not control either brakes or gearbox when going downhill.
I have to travel the A30 fortnightly and for the past two trips I have been able to use cruise control a fair bit of the journey from Launceston to Truro. On both occasions the cruise control has stopped the speed increasing downhill. Travelling westwards, on Bodmin Moor there is quite a steep hill off the moor into the Fowey  valley and up the other side where the Jamaica Inn is located. Cruise control set at 70mph, over the brow and down the steep climb, I noticed that the car held 70 mph, no running away. On the trip yesterday I made a conscious effort to pay attention to what was happening. There was no lurching, nor a sudden rise in engine revs just a definite holding back. Also, I looked at the gear indicator and saw that the car had of it's own volition changed down into 4th gear and as the hill bottomed out and we started to climb, engine revs increased and gears changed up to 6th. Moving further along into the road works, which are subject to 40 mph there are two moderate downhills. In both cases the car, just ran way no control from the cruise control, so I had to apply the brakes. I believe I am correct in the fact that when the throttle is completely closed no fuel is injected into the cylinders, however despite this the car will increase speed unless brakes are applied on a downward slope.
Does the Jazz have some clever software in the cruise control to prevent 70 mph being exceeded downhill. There is no doubt that the cruise control definitely controlled downhill speed when set at 70mph.

applicationcen

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Re: Cruise Control and its ability to control speed downwards
« Reply #1 on: January 25, 2017, 03:19:54 PM »
The i-shift cruise programming attempts to very roughly maintain the target speed. I also agree with you that using the brake on a down hill is a precise way to induce engine braking and have it maintained.

On uphill segments I rather manually flip it down rapidly to 4th or even 3rd then knock it back to auto, rather than hit the accelerator and lose the cruise speed setting.

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #2 on: January 26, 2017, 02:47:03 PM »
The point I was trying to make was that I did NOT brake when going down the hill at 70mph. I purposely had both feet flat on the floor. ( No traffic about) The car did all the work.
At 40 mph I still had to brake to stop the car running away which of course deselects the cruise control. What also impresses me is the hill in question by Jamaica Inn is pretty steep and the car maintained 70 mph  going up the hill with the box changing up and down to maintain the speed. This occurs at all times going UP a hill but going down is a different matter. I have found that cruise control is pretty good at maintaining the set speed. I merely wondered why cruise control would involve the brakes/engine braking at 70mph and no other speed.

applicationcen

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Re: Cruise Control and its ability to control speed downwards
« Reply #3 on: January 27, 2017, 09:51:11 AM »
Ah, I agree.

I actually get frustrated that it wont free wheel faster on a long fast slope. However Ill do the same test as you say when I next go down Telegraph Hill and see what I experience.

culzean

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Re: Cruise Control and its ability to control speed downwards
« Reply #4 on: January 27, 2017, 05:26:27 PM »
70 mph is probably terminal velocity for a light car like Jazz on most UK hills, where wind resistance and tyre drag balance gravity.  There is a long steep hill close to where I live and the Jazz mk2 will not go over 70 in 5th without adding power from loud pedal. However to limit the speed to 40 I would have to be in second or third gear because the wind resistance is not enough on its own to limit speed and help from engine braking is required.
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #5 on: January 28, 2017, 11:48:36 AM »
I have asked Honda about this matter, it will be interesting to see what there answer is.
As to the hill in question if I let the car go it will reach 90 plus  by the bottom of the hill , no problem. I hasten to add I have only done this once  with eyes everywhere and no traffic. Purely as an evaluation of the car. I want to keep my nice clean licence.
As an aside I am surprised just how willing this little 1.4 engine is and I find I have to be very careful about speed limits in the lower quadrant.  6th gear in a 30mph area is decidedly dodgy. Yes I know I could overide the I shift but what is the point. I just have to be aware.
I will post the reply from Honda. I do not have much faith as the last question I asked about an alleged dip stick on the I shift box elicited the answer take it to a Honda dealer. It was one of them in the guise of their service  manager that told me the I shift box has a dip stick. It doesn't it has a level plug. The CVT box has a dip stick. I am extremely grateful to whosoever published the manual on line.

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #6 on: February 22, 2017, 10:35:38 AM »
Whilst I appreciate the problems being experienced with a MK3 aren't funny, the comment about checking with the manufacturer has some bearing on my query over the Cruise Control.
I E mailed Honda with the query and received a bit fat zero. I then sent another, which did elicit an automated reply that a technician will be back to me within 5 days. Zilch. So I shall wait till the end of the month and then write a letter.
I know this is nowhere as important as the problems with the MK3 but come on if they can't answer the question who can?
I am still a bit miffed by a) the main dealer service manager and his answer to how does one check the level on an I shift. It has a dip stick NO it doesn't the online manual tells me it's a level plug. Honda couldn't tell me that just told me to contact the dealer. b) the fight to get faults fixed on a used car that had been gone through thoroughly!!!!!!!!!!!. and c) paintwork problems that were nothing to do with them despite 2 years warranty. The main dealer doesn't deserve the car because time after time I read here about poor after sales service.
Lets hope Honda sort the MK3 problems out.

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #7 on: March 02, 2017, 10:02:16 AM »
Yesterday, was an I hate Honda day. After 2 Emails and a mail shot encouraging me to contact my dealer about a new Civic at fantastic discounts I am afraid it was 'the gopher gets it'.  Two Emails with a simple question about the Cruise Control being ignored and finding that the poor paintwork I complained to the dealer about and ignored,  now getting worse, a letter was composed to Honda HQ.  The Jazz is the ONLY car I have bought from a main dealer and to be honest I am not impressed. I feel so sorry for those that have spent a lot of money and found they are 'lumbered' with a problem that the dealer and manufacturer are trying to fob off. Mine thankfully are not as serious as some.
I don't suppose Honda will take any notice but basically after listing my gripes I told them that the little Jazz essentially a nice little car doesn't deserve the manufacturer and main dealer it is lumbered with. I also made the point that given my experience and those I read about on Club Jazz, it is no wonder Honda are losing their market share.  Given the mark up on both s/h and new cars, it is disgusting that when it comes to problems that should have been sorted prior to sale are left in the hope that some fool will be conned into paying out. 
Sorry chaps it was worth the stamp and paper. I finished by saying why should I buy a new Honda after my experiences with the one I have?. I am grateful to have the facility whereby I can let off steam.

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #8 on: March 03, 2017, 02:04:55 PM »
Yes the moany old so and so is still off on one. Today, in my inbox was an Email from the Honda engine shed? it was basically asking me if I really wanted to unsubscribe to their site. I, yesterday unsubscribed to Honda and a few others to rid myself of some of the junk. I have never been asked before if I really meant to unsubscribe. The fact that Honda could not reply to TWO Emails was rather rubbing the salt in the wound.

guest6040

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Re: Cruise Control and its ability to control speed downwards
« Reply #9 on: May 01, 2017, 02:24:54 AM »
Having had several cars with cruise control,including 2 Preludes, '92 & '96; + various large Aussie Ford Fairlanes, Falcons,  I was pleasantly surprised to find our Jazz has Adaptive C/C ! Meaning it will accelerate & brake (with engine/gearbox) the vehicle to a set speed. It appears it is std with Jazz in all models ! Yippee ! When going downhill it takes a bit of overrun before it activates and changes down 2-3 gears to bring the car back down to speed, as there is not much engine braking with the auto version. Very useful ! :o ;D :'(

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #10 on: May 12, 2017, 02:41:40 PM »
I have been in considerable correspondence with Honda over this question. Letters have been backwards and forwards but today's answer I am afraid is the end. I give up.
I have tried several ways to explain what I am asking but I get anything from take it back to your dealer, we have a technical department that is available for dealers and today it is we have been in contact with your dealer and they say your car is too old to have the later type system installed. When did I shift cease to be fitted? I asked why they could not ask their technical dept direct. In each and every case the point of the question has been ignored. and the repetitive take it back to the dealer. The service manager of which did not know how to check the oil level in an I shift gear box.
This was the last effort to get an answer ' Is the software on the I shift gearbox programmed so that when using the Cruise Control set at 70mph, it controls downhill speed to remain at 70mph by gears and throttle which does not happen at lower speed settings' I now doubt my ability to converse with the human race. PLEASE I would appreciate any observations as to whether what I ask is reasonably clear. Criticisms are welcome.

VicW

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Re: Cruise Control and its ability to control speed downwards
« Reply #11 on: May 12, 2017, 03:33:30 PM »
When did I shift cease to be fitted?

2011 facelift.

Vic.

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #12 on: May 13, 2017, 11:41:40 AM »
In my original letter to Honda, I ended it with if you do not know then please say so. My frustration is because they kept banging on about taking it back to the dealer and they will road test it and report on the fault. Each reply to Honda has 'there is no fault this is merely a technical inquiry'
The latest reply is I am afraid ambiguous . Do they mean a later model car as Vic W has informed me was 2011, which of course is a CVT .Do they mean a MK3? So why could they have just said not fitted to Ishift. OR did they mean it was fitted to later models fitted with I shift. We know that our Australian cousins have access to the true auto box and a report of reactive cruise control. It does not affect those fitted with a manual box.
I really cannot get my head around a manufacturer who has a technical department asking a dealer for advice. All I am trying to do is keep my aging brain active with questions however pointless they may appear to some.I always understood an inquiring brain is an active one and I happen to believe that asking questions is the only way to learn.
I also asked in my last letter to Honda 'when are the airbags likely to be replaced in the 2010 cars?'. IGNORED..

culzean

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Re: Cruise Control and its ability to control speed downwards
« Reply #13 on: May 13, 2017, 12:14:25 PM »
I also asked in my last letter to Honda 'when are the airbags likely to be replaced in the 2010 cars?'. IGNORED..

My wifes 2011 Si has just had a recall letter for airbag.
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

guest5079

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Re: Cruise Control and its ability to control speed downwards
« Reply #14 on: May 14, 2017, 02:39:08 PM »
Culzean
May I ask if it is  to do the job or one of the don't do anything till we notify you letters of which I have two.
Can you tell me what part of the UK your dealer is please?
Thank you

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