Author Topic: So maybe something is wrong after all :(  (Read 9253 times)

Deeps

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Re: So maybe something is wrong after all :(
« Reply #15 on: November 30, 2016, 08:59:06 PM »
My car sometimes (rarely)  throws a tantrum when starting, I have always put it down to the stop start system being confused. It will seem to be reluctant to fire up and then run rough for a couple of seconds. It has happened in my garage and in a car park, my wife mentioned that the car was reluctant to start a few days ago. My thoughts so far are that the engine had auto stopped and then been switched off. It has not happened often enough for me to consider it a problem. (yet).
« Last Edit: December 01, 2016, 07:23:38 PM by Deeps »

andruec

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Re: So maybe something is wrong after all :(
« Reply #16 on: December 01, 2016, 08:48:44 AM »
Did the courtesy car have a night in the garage? If so, perhaps try leaving the car outside the garage and see if it is happier.
Good idea, but no. It just sat on my drive all day. It was a chilly day but it started just fine at the dealers in the morning (once I realised I had to hold the clutch down).

Deeps

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Re: So maybe something is wrong after all :(
« Reply #17 on: December 01, 2016, 09:57:14 AM »
Unless there is a temperature sensor fault I doubt if ambient temperature in the UK makes much difference. Hondas are sold from the arctic to the tropics and lead an easy life in our temperate climate. I have seen them in the north of Norway on studded tyres way below freezing (-15C) and in the south of India in 40C, they all seemed to work OK.
« Last Edit: December 01, 2016, 07:26:04 PM by Deeps »

andruec

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Re: So maybe something is wrong after all :(
« Reply #18 on: December 01, 2016, 08:00:14 PM »
Edit:Just saw your post of the 30th, Deeps. That sounds familiar and that's what I thought all through summer. Just the idle stop confusing things. At least it's one other owner seeing something awry so perhaps we can rule out my magnetic personality now :)

Deeps

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Re: So maybe something is wrong after all :(
« Reply #19 on: December 01, 2016, 08:48:03 PM »
Maybe we are sensitive souls who are in tune with our cars. That does not explain Mrs Deeps noticing a glitch, her mechanical knowledge does not extend beyond turning the key. :-)
« Last Edit: December 02, 2016, 08:36:42 AM by Deeps »

Deeps

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Re: So maybe something is wrong after all :(
« Reply #20 on: December 02, 2016, 08:32:12 AM »
Having slept on the engine start anomaly, the engine needs fuel, a spark, and compression occurring at the right time to start and run. I wonder if the engine stops in a particular position It takes a second or so to get things lined up. The variable is the camshaft position, it is electronically controlled and hydraulically (oil pressure) operated. My thoughts are that the overall engine system can take a second or so to get set up after certain stop conditions.

This may be complete rubbish, if it is possible I have no idea what causes it.

andruec

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Re: So maybe something is wrong after all :(
« Reply #21 on: December 02, 2016, 09:36:56 AM »
This may be complete rubbish, if it is possible I have no idea what causes it.
I think that's possible but it does seem to me to have a weather component about it. Mine stopped having the problem a month or two after I bought it. At the time I said I thought it was because I'd learnt to give the idle stop time to settle after restarting when I parked in my garage. As a theory it fitted very well. It even explained why I never had the problem in the evening at work - I reverse into my space and idle stop never activates there.

But now it seems that the reason it stopped could just have been that I bought it in early March and a couple of months later it's summer. Certainly it seemed to kick off again in October.

My current theory is something MAF (Mass Air Flow) related. I'm no mechanic but reading up on it it would explain a lot. It might also explain the occasional 'numb accelerator pedal' I get. That too seems to have crept back. It's not as bad as when I first got the car but I have recently had a couple of occasions when trying to accelerate out of a roundabout it's felt like the accelerator pedal is ignoring me. When I've pressed the issue (ha ha) the car has surged forward.

http://www.carsdirect.com/car-repair/how-to-tell-if-you-have-a-faulty-mass-airflow-sensor

The only thing that doesn't seem to match is fuel consumption. I'm driving 12 miles each way during the week including a somewhat tortuous evening rush hour experience and despite it being winter I'm still managing (measured pump to pump) 51 mpg.

Then again it's clearly intermittent so maybe it just doesn't happen often enough to impact fuel consumption. I don't think 51mpg is bad for what my car is doing. On long journeys (like last weekend) it self-reported nearly 60mpg for a steady 60mph run.
« Last Edit: December 02, 2016, 09:40:41 AM by andruec »

culzean

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Re: So maybe something is wrong after all :(
« Reply #22 on: December 02, 2016, 09:44:36 AM »
The camshaft position is not altered by the VTEC system, its relationship to crankshaft position remains fixed,  What happens with VTEC is that the camshaft has extra cam lobes with different profiles and there are also extra rocker arms which follow these cams but are normally not connected to main rocker arm,  so they just freewheel and do not affect valve operation positions. The extra arm(s) can be linked or un-linked to main arm (the main arm is only one long enough to touch both the cam and the top of valve, the extra arms are only long enough to touch the cams) by hydraulic pins which have springs to return them to retracted (unlocked) position when engine oil pressure not pushing them forward,  this oil pressure to pins is controlled by ECU via an on-off solenoid valve,  but in the absence of oil pressure (engine stopped) the pins will be returned to unlock position by their springs, always leaving the valve timing in its basic position for starting and low rev operation.
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

Deeps

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Re: So maybe something is wrong after all :(
« Reply #23 on: December 02, 2016, 11:51:56 AM »
The camshaft position is not altered by the VTEC system,

I agree, but the intake camshaft position (timing) is altered by the VTC (Variable Timing Control) actuator. It is under the lump in the cam chain cover just behind the dipstick.

http://www.honda.co.nz/technology/engine/VTC/
« Last Edit: December 02, 2016, 12:31:01 PM by Deeps »

culzean

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Re: So maybe something is wrong after all :(
« Reply #24 on: December 02, 2016, 01:19:08 PM »
http://asia.vtec.net/Engines/ivtec/index.html

Yes you are right,  Honda have refined original VTEC principle by adding VTC and introducing a helical linkage between camshaft and its driving sprocket to enable the intake cam shaft to be moved  relative to its driving sprocket.  This seems to be to make VTEC system operation smoother and get rid of the noticeable 'switch-over points' that used to be a feature of VTEC alone.

« Last Edit: December 02, 2016, 01:21:40 PM by culzean »
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

Deeps

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Re: So maybe something is wrong after all :(
« Reply #25 on: December 02, 2016, 01:58:43 PM »
I think you will find that Honda do not use the system you have linked to. That VTC sprocket is a belt drive spiral system. If you search for Honda VTC in Google images it is the type with four internal lobes which act as vanes to move the camshaft using oil pressure from the control valve.

Deeps

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Re: So maybe something is wrong after all :(
« Reply #26 on: December 02, 2016, 02:49:50 PM »
As my car has only had a brief cough on start up on three well spaced occasions I am not concerned at the moment. As I am from the age of manual and then dodgy auto chokes the odd splutter at start up is no problem.

andruec

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Re: So maybe something is wrong after all :(
« Reply #27 on: December 02, 2016, 03:44:51 PM »
As my car has only had a brief cough on start up on three well spaced occasions I am not concerned at the moment. As I am from the age of manual and then dodgy auto chokes the odd splutter at start up is no problem.
Funnily enough I'm less concerned now that I know it's not restricted to my vehicle. Possibly mine is a particularly bad example but it seems to me that it's just a characteristic of the model. That gives me confidence that it'll always start on the second attempt and maybe one day Honda will fix it.

I've just added it to my list-of-things-wot-Honda-got-wrong.

It's quite a list which will be useful in two or three years when I consider my next car purchase.

Deeps

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Re: So maybe something is wrong after all :(
« Reply #28 on: December 02, 2016, 03:52:08 PM »
Mine has never refused to start first time.

culzean

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Re: So maybe something is wrong after all :(
« Reply #29 on: December 02, 2016, 04:43:05 PM »
I think you will find that Honda do not use the system you have linked to. That VTC sprocket is a belt drive spiral system. If you search for Honda VTC in Google images it is the type with four internal lobes which act as vanes to move the camshaft using oil pressure from the control valve.

Thanks for the up to date info
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

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