Engine Vibration

[guest979]

Hi

We have recently purchased a 2005 Honda Jazz with 40k miles which is running fine apart from a rough idle.  With the bonnet open the engine seems like its struggling during the idle although the revs are under 1k.  When driving it seems to be fine.  The vibration is similar to a washing machine on the spin cycle. 

Is this common on the Jazz or could it be due to some fault?  Any replies will be greatly appreciated.

Thanks

[guest809]

Definitely not usual but I will leave others more technically able than me to suggest solutions.

[guest255]

I have no problems during idle but have heard of cases of the egr valve giving problems. Also worth checking all connections are ok esp spark plugs and associated components.

[guest979]

Many Thanks for the replies, I have checked the connections today and also removed the spark plugs which look ok.  In addition to this I tried to disconnect the connector to the EGR which had no impact.  When the connector to the EGR is disconnected would that disable the EGR?  Before removing the connector I removed the EGR unit and sprayed wd-40 within the opening, again has had no impact.

[culzean]

Firstly removing the EGR plug will prevent it opening but if it is stuck open anyway it will have no effect, also removing the plug will disconnect the position sensor as well and may confuse the ECU.  If the EGR is stuck closed it should not affect the low down running and should only affect the emissions at higher revs.

I would NOT recommend using WD40 on the EGR as this will not have any effect on the carbon deposits and will probably just gum it up further (WD-40 tends to dry to a sticky goo anyway, but given the heat of the EGR it may well turn into superglue). Use a carburettor cleaner if you want to try and clean the EGR. Otherwise make a tinplate or other thin metal plate to fit under EGR and block the hole completely, only use this for diagnosis, don't leave it in place permanently.

Misfire may be due to ignition problem, try disconnecting and replacing the 2 pin plug from each ignition coil in turn with the engine running at tickover (its only 12volts), if the removal of a plug has no effect on the misfire then suspect that coil pack or sparkplug, if it makes the problem worse with the plug disconnected then that coil is probably OK.  If you do have an sparkplug or coil problem then you may also notice some 'pinking' when going up hills or accelerating.

[guest979]

culzean, I disconnected the front spark plug connectors and this had no impact on the engine vibration, I then reconnected and disconnected the front and back plugs in pairs, this made the vibration worse.  When each connected was plugged back in the vibration went back to normal.

I also read that it would be useful to do the ecu idle procedure which I did which again had no impact.  Not sure what else to try apart from booking it into the dealership, any further ideas will be appreciated.

Thanks

[guest684]

I disconnected the front spark plug connectors and this had no impact on the engine vibration,

With my limited general mechanical knowledge(!): It seems therein lies your problem as I'm guessing disconnecting these connectors should make a noticeable difference to your engine idle -as it did when you removed the rear connectors.  It may be worth checking the leads themselves. (-not sure how you would do this as I am not sure it would be possible or safe to swap your leads around).

I understand leads are quite expensive.

[culzean]

tjd - If you disconnected the 'front and rear ignition leads in pairs' then you would effectively have disconnected BOTH spark plugs in each cylinder.  I am not surprised that the vibration got worse as you hade turned a 4 cylinder engine into a 3 cylinder.  Either disconnect the front OR rear plug, one cylinder at a time, as this will still leave at least one (this was the purpose of the exercise) working spark plug per cylinder.

[guest979]

I disconnected each connector and then reconnected which has made no difference, I have also checked the fuses for the front and rear spark plugs which again are fine.

[guest765]

TDJ thats a bit of info i didnt know........i didnt know the spark plugs have fuses......posh or what.............

[guest979]

joejazz, I was suprised to see the service manual detail the fuses which were fuse 2 and 24 both are 15 amp.  They were both ok and are located under the steering wheel fuse box.

[guest979]

After reading a few other articles I decided to give the car in to Honda to have the valve clearance checked/adjusted.  As this has not been done in the past I thought it may resolve the engine vibration issue.  After the clearance was done the same issue persisted 

I have now put in some new spark plugs and was going to replace the air filter when I noticed a substantial amount of oil within the airbox.  The oil had also covered the throttle body.  I suspected the PCV valve which is located under the intake manifold, this was removed and the PCV valve taken out.  It was stuck and made no noise when it was shaken.  Hopefully when I put a new valve in this should cure the initial issue with the rough idle.  Will update this post once I install the new valve.  Thanks for all the help.

[culzean]

tdj - Instead of taking in the car to Honda dealer for the valve clearances to be checked (at a cost of around £300) why not take it in and ask their opinion on the vibration problem?  They have all the diagnostic equipment to check out the engine and could surely come up with a cause at less than £300.

[guest5360]

Sorry for digging out this thread but are there any updates on this issue?