Cel on Code P0303
 

Hi
We had the cell light come on a few weeks back and had the local Honda Dealer do the code check and ECU Re-set.
On this Occasion the code was P0303 a misfire on Number 3 they gave it back to us but the light came on again so it is back in.
OK having read the posts in FAQ it would seem that if it comes up with the same fault this time i have a component failure on No 3?

My Questions are as follows

It would seem that it could be coil pack (are these one per plug?)
Plug
Valve issue clearance maybe? (are they checked as part of regular service?)

I hope to have some more info later from Honda but interested to hear if owners may have had simliar problem

Cheers Liam

Not uncommon.

One coil per cylinder.

Really tricky to diagnose ove the net but it could be:

Plugs / Injector / Coil Pack / Lambda / MAP / Crank sensor / Engine problem

One tactic is to replace the plugs and then swap coil packs around to see if the fault follows to another cylinder. Same with the injectors if that doesn't work.

Some other tips in the link at the bottom of my signature.

Can be valve clearances and these are checked on some of the service intervals.

There are very recent posts on here along similar lines. Coils, injectors etc all possibles and first place to check.

Ok The fault code shows No 4 now so not likely to be one plug or coil
Honda are doing the valve clearances as i type to see what we find!
I have asked them to note the existing for my reference.

Liam

If its moving between cylinders you can nearly rule out the plugs / injectors / coils and concentrate on other stuff 1st. Of that lot i'd say injectors are most likely.

It now looks like a common type fault.

Valve clearances if they will do it.

See if it comes back.

If it does you have to start looking at the things common to the ignition system (map / lambda / ECU wires etc)

OK the update is that Honda checked all the valve clearances.
The Exhaust valves where all tight (not good)
My wife reports the car feels so much better on the road so i hope this is the cure!

As a point of interest the car was recently on a Rolling Road and was 30 odd BHP down on the book figure.
If the clearances were tight i am guesing the valves may not of been fully closing when hot so it could help explain the low figures??

I intend to Roll the car again soon to double check!

Thanks for your feed back guys and i hope we have the cure.

Liam

Correct and good work!

Be very interested for you to report the RR figures back on this post.

I aim to Roll the car soon and will post the results hope to find nearer the book figure.
In the mean time the car seems much better so hope it stays tha way!

Liam

Ok the Issue with the car continues.
The car ran great after the valve clearences were done and on the Dyno a small inprovement too but still low compared to book.
The car gained 5% 10 BHP but still only delivers 212 BHP

The real problem is the return of the Misfire on No3 fault Code!!
Last week it started running poor again i called the RAC to find the fault code was again No3 Misfire
This time i decided to do some ground work
Full compression check showed no issues around 200 PSI all around
So then i figured to do what HONDA have not!
I swapped no 3 coil pack for no1 and ran the car it threw the light again.
I had the code checked again to find fault on No 3 Still!!

So i have moved No3 plug to No1 to see if that moves it??

The question is what else could be causing the No3 misfire code
Supply to ingnition coil No3?
Injector Issue?

Going to have to go back to Honda and try to resolve this.

Thanks for reading the post and for any help you can offer

Liam

Injector is quite likely given you have eliminated other options.

Apart from swapping them, someone recently suggested you can measure the resistance with a multimeter, but I didn't really investigate as to wether this was a valid test or not.

I'd just swap it with number 1 and go from there.

Good to see you have done the obvious and tried plug / coil pack swap.

If only everyone were like you!