Clubjazz - Honda Jazz & HR-V Forums

Honda Jazz Forums => Honda Jazz Mk1 2002-2008 => Topic started by: guest6479 on July 10, 2017, 08:19:59 PM

Title: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 10, 2017, 08:19:59 PM
Hi Everyone,

I've got a curious problem my Jazz - during acceleration the car jerks or has a flat spot (not sure what to call it exactly). I doesn't happen seem to happen above 60mph at all, when just lightly pressing the accelerator, or if you really put your foot down, just during normal acceleration. It might happen once, or a couple of times getting up to speed.

Does anyone have any ideas of what to try? or experienced the same thing and found a solution? 

Thanks,
Ben
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 10, 2017, 09:51:44 PM
Have the rear set of spark plugs been changed?
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 10, 2017, 09:56:57 PM
Thank Jocko - I'll check that out in the morning. It has a service not too long ago so i'm guessing yes, but i'll check with my guy at the garage.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 11, 2017, 07:40:03 AM
Lots of garages don't realise that our era Jazz has 8 spark plugs. The second 4 are buried down the back of the engine and are well hidden. Those garages that do know about them often don't change them because of the PITA factor, so a recent service is no guarantee they have been done. Other, well meaning garages, will change the front plugs, see they are not really needing changed, so don't even look at the back ones assuming they will be the same. However it may be several services ago since they were in fact done.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 11, 2017, 08:15:57 AM
Lots of garages don't realise that our era Jazz has 8 spark plugs. The second 4 are buried down the back of the engine and are well hidden. Those garages that do know about them often don't change them because of the PITA factor, so a recent service is no guarantee they have been done. Other, well meaning garages, will change the front plugs, see they are not really needing changed, so don't even look at the back ones assuming they will be the same. However it may be several services ago since they were in fact done.

+10     

rear plugs are a good place to start,  it is cheap enough to change all 8 so at least you know all plugs are good.

If the rear plugs are neglected for too long it can cause failure of a coil pack,  the coil pack will try to develop enough voltage to jump the ever widening gap as the plugs wear,  if gap has got too wide this can stress coil insulation and cause spark over,  once the insulation has been carbonised it will continue to track over, short circuiting the spark so basically the plug will no longer get a spark,
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 11, 2017, 11:37:28 AM
Thanks everyone - had a chat with my mechanic and he said he had a look at the rear plugs and thought they looked ok so left them... So I'll get them replaced in the coming days.

culzean - So if the plugs are replaced and we still have the problem, is the coil pack next on the list?


Lots of garages don't realise that our era Jazz has 8 spark plugs. The second 4 are buried down the back of the engine and are well hidden. Those garages that do know about them often don't change them because of the PITA factor, so a recent service is no guarantee they have been done. Other, well meaning garages, will change the front plugs, see they are not really needing changed, so don't even look at the back ones assuming they will be the same. However it may be several services ago since they were in fact done.

+10     

rear plugs are a good place to start,  it is cheap enough to change all 8 so at least you know all plugs are good.

If the rear plugs are neglected for too long it can cause failure of a coil pack,  the coil pack will try to develop enough voltage to jump the ever widening gap as the plugs wear,  if gap has got too wide this can stress coil insulation and cause spark over,  once the insulation has been carbonised it will continue to track over, short circuiting the spark so basically the plug will no longer get a spark,
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 11, 2017, 12:20:21 PM
had a chat with my mechanic and he said he had a look at the rear plugs and thought they looked ok so left them... 
To me this is a cop-out. No mechanic in the world is going to go to the hassle of checking the rear plugs and not change them. Even if they looked brand new he would still change then rather than have to go through all that again.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jem on July 12, 2017, 11:51:24 AM
had a chat with my mechanic and he said he had a look at the rear plugs and thought they looked ok so left them... 
To me this is a cop-out. No mechanic in the world is going to go to the hassle of checking the rear plugs and not change them. Even if they looked brand new he would still change then rather than have to go through all that again.

I agree it sounds like he didn't check or change them, maybe didn't know about them, and just said that to cover himself.

I changed all my plugs earlier this year and it was easy. Just got to make sure you take your time and don't cross thread anything. The only thing I found useless was the plug socket from Halfords. It would come off the extension bar in the hole. So I had to use a normal socket to undo the plug then a bit of garden hose to push over the top and pull it out.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 12, 2017, 04:44:17 PM
Sounds as though mechanic didn't check rear plugs but decided to cover himself just in case you checked them and found that old plugs still fitted.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: degzi on July 20, 2017, 12:05:24 AM
I recently had a mild flat spot on acceleration, I couldn't pin it down to a certain speed etc.
However I had some redex which I got on the cheap for about £1 seemed to clear it.
The other day I checked my plugs and found that they were quite oily, It looked like someone had put oil or something on the threads and it overheated and gummed the ceramic. I cleaned it off and wire brushed the electrodes while I was at it, its been fine ever since. Checked the gap and it was 1.1mm.

Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 24, 2017, 11:42:50 PM
Hi Chaps,

It took me a while to get it sorted - I ended up changing the spark plugs myself to make sure it was actually done, and done properly.

The sparks looked pretty worn to me (pic attached), and with the new plugs installed it's solved the hesitation/ flat spot problem! (Correct plugs and spacing) Yay! But... the car is still running a little rough with a bit too much exhaust noise - any ideas of what to chase? Faulty coil pack?

 

Thanks for all the help so far :)

[attachment deleted by admin]
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 25, 2017, 05:50:36 AM
With the engine running stick your hand over the exhaust pipe. This will show up any leaks. Check condition of middle box behind offside sill.
Coil pack normally shows up as an OBM code. Do you have access to an OBM reader?
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 25, 2017, 08:35:07 AM
Hi Chaps,

It took me a while to get it sorted - I ended up changing the spark plugs myself to make sure it was actually done, and done properly.

The sparks looked pretty worn to me


Those plugs have been in a long time, gap looks huge ( did you measure it ? )

I know I sound like a worn record with Redex injector cleaner but pop some in,  it is cheap enough and certainly will do no harm.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 28, 2017, 01:30:31 PM
The sparks gap was massive probably 2mm! Must have never been changed!

I've made a couple of videos to show what's going on.

1. Intermittent erratic idle - 2. Engine to exhaust noise - not sure if the sound will be good enough to tell what's going on.

Aslo I have one of those wifi ODBII testers, I used it before I changed the spark plugs and there were not errors. Just had a look again now and it's pulling up error "Code P1351 type Powertrain" - I've reset and take her for a spin later and see if it pulls up the same code again...

P.S i'll pick up a bottle of redex asap :)
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 28, 2017, 01:58:06 PM
Read this:
http://www.hondafitjazz.com/manual/A00/HTML/98/SAA2E98K72100081155FAAT10.HTML (http://www.hondafitjazz.com/manual/A00/HTML/98/SAA2E98K72100081155FAAT10.HTML)
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: JohnAlways on July 28, 2017, 02:04:22 PM
Was just going to post the same :) via the Fittreaks forum http://www.hondafitjazz.com/manual/A00/HTML/98/SAA2E98K72100081155FAAT10.HTML (http://www.hondafitjazz.com/manual/A00/HTML/98/SAA2E98K72100081155FAAT10.HTML)
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 28, 2017, 02:11:15 PM
Sounds like those massive rear plug gaps may have damaged a coil.   Hope you mention the plugs to that mechanic of yours,  better still show him the ones you took out and ask him if they still look OK (and give him a specsavers voucher at the same time).
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 28, 2017, 04:41:50 PM
Sounds like those massive rear plug gaps may have damaged a coil.
The code actually points to a front coil. You didn't swap a front to a rear did you? They are different and not interchangeable.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 28, 2017, 05:35:38 PM
Sounds like those massive rear plug gaps may have damaged a coil.
The code actually points to a front coil. You didn't swap a front to a rear did you? They are different and not interchangeable.


@benferrari

When did front plugs get changed,  did you change all 8 and find that they all had a large gap or was it only rear ones ?
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 28, 2017, 06:47:13 PM
I changed all the plugs - the front ones weren't as worn as the back ones thou. Looked like the large spacing was due to wear... 
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 28, 2017, 09:25:14 PM
I changed all the plugs - the front ones weren't as worn as the back ones thou. Looked like the large spacing was due to wear...

Every time the plug sparks the gap is widened slightly by the erosion of the metal by the spark and combustion heat - the reason iridium and platinum plugs last so long is that they are much harder and resistant to heat and the spark.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 30, 2017, 12:09:22 PM
I've done about 150miles in the car since resetting the codes and it's pulling the any codes yet. Should I follow the trouble shoot link as posted above, or try something different?

Thanks!
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 30, 2017, 12:38:26 PM
If it is running okay and not creating codes I would just drive it. I had an Engine Management Light months ago. It reset and I have never had any further problems. Same thing happened with my Volvo. Occasionally a spurious fault will flash up and may never return.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 30, 2017, 01:34:32 PM
Cool - it's not running great is the thing, sounds quite rough and feels underpowered during acceleration.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: culzean on July 30, 2017, 01:38:10 PM
Redex - cheap enough to try
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 30, 2017, 01:58:03 PM
Done the redex - didn't really help :(
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 30, 2017, 02:01:16 PM
Check that one plug and coil pack. You could even replace that one plug again. I once had a plug change and then had issues. Turned out one of the plugs was faulty.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest5079 on July 30, 2017, 02:10:39 PM
Jocko is quite correct DO NOT ASSUME AS ITS NEW ITS OK.
Whilst I appreciate it was a while ago, I have never forgotten. A straight six missing, started with plugs then plug leads and plug caps then distributor cap, then condenser and finally coil. ALL NEW. We had ruled out mechanical faults. Despite all attempts still missing. So we started again and what was it? a flipping faulty plug cap. In those days we didn't charge the customer for the hours. I wonder if that would apply today.
Of course it couldn't happen today with their computer hook ups?????????????
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: guest6479 on July 31, 2017, 12:06:06 PM
Thanks guys - I've tested all the coil packs, they're all working - If they're all working does that eliminate the faulty plugs too?

Anything else this rough running could be?
- a bit noisy
- feel under powered during acceleration
- intermittent idle
- throaty exhaust
- slight tapping noise from engine

*The new plugs solved the jerking*

Thanks,
Ben
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Hopipola on July 09, 2023, 04:25:47 PM
Have you bud been able to resolve your jazz. I have a next edition but by sounds mine has the same problems that yours have.
Title: Re: Honda Jazz flat spot / jerking during acceleration
Post by: Jocko on July 09, 2023, 09:45:06 PM
Change all eight spark plugs.