Misfire on start up, since oil change

[Dan Evans]

Hi guys looking for some help regarding a newly developed misfire on my dc5.

-Since an oil change last week my teg has ran with a misfire for a split second on start up, before returning completely to normal,

- yesterday on a cold start it ran on three cylinders for around a minute, before returning to normal

-today it wouldn't start and was probably trying on two cylinders. I left it for a few seconds and tried again, it was still struggling but this time started and then returned to normal after a few seconds.

So I tried to figure it out tonight, it does it on cold start, and it also does it after being left on a hot engine for 10 minutes...so it's not a cold start issue. If you turn the engine off and then crank it straight over again it starts perfectly, Coil packs, spark plugs, loose connections etc wouldn't be limited to start up so that's out of the window I think. My dad thinks the hamp filter could have a faulty valve and isn't maintaining oil pressure, hence why after being stood it doesn't start, so I may get a new genuine honda filter tomorrow. Does anyone have any suggestions? Or agree with the above?

Thanks in advance

 

[beppe786]

check injectors. . i had similar odd problem changed everything ended up 1 faulty injector

 

[davidpingu]

Are you getting any fault codes at all Dan?

It may be completely unassociated but a similar problem I had one day after giving it some vtec was about 4 hours later I returned to the car, it started fine and ran for about 10 mins when all of a sudden it cut out. On restarting it wouldn't run unless I kept revs above 1.5k and it was very lumpy indeed. If you have similar issues it could be a faulty VTC spool valve. These can become clogged with oil and make the car run very rough indeed.
It's only a shot in the dark based on my own experience and obviously difficult to give any certainty from a keyboard but perhaps something worth considering if your other ideas don't come to anything.

Good luck and don't be disheartened. Usually finding the cause is the biggest issue. Once you find it it's usually a straightforward fix.

 

[Dan Evans]

Thanks beppe, it could be and work a check, but when it's at its worst I'd say it's more than just one faulty injector. Sometimes it's as though it's one, but then other times it would have to be two faulty as it quite bad on start up.

No engine management lights on either so I can't scan anything off it. I've never really known a faulty filter but I might try that today for the sake of a tenner and a bit of oil.

Any other suggestions? Worried I could end up chasing this for a while

 

[Rob.]

Could be a dodgy injector..

If its running on 3 cylinders try pulling a plug of each coil pack one by one until you find which cylinder is at fault (so if it makes no difference when pulling a plug off that cylinder is the problem) then move the injectors about an see it the missfire moves to the other cylinder

If non of this makes any difference then its something else electrical !

When my injector failed was also a small missfire at times then really bad other times to the point where it was backfiring just on idle !

 

[Dan Evans]

Cheers for the suggestion, although the misfire is in on average between 2 and 5 seconds so it might be a bit difficult in that respect. I started it three times today with no misfire and thought it might have cleared, but then the last two times it has misfired slightly at start up again

I didn't try the oil filter today as I thought it was too much of a long shot, likely a coincidence since the oil change. At least it's starting again and slightly better now. Just confusing as it runs so well after the initial start up.

Will see how it is tomorrow and maybe check Injectors

Cheers

 

[wj51fut]

Check the spark plugs too. Make sure they are not coked up. Check the coil packs are on tight as well. Look for any lose wiring around the ignition area. It will most likely be something simple. You might have knocked something whilst doing the oil change. Oil pressure switch is right next to the filter. And the CKP (crank position sensor) is just below. Could be one of those.

 

[ghhtty]

Oil pressure switch is right next to the filter. And the CKP (crank position sensor) is just below. Could be one of those. Fut coins