Misfire with P0301 & P0304 codes

Misfire with P0301 & P0304 codes

Author
Discussion

PaulKemp

Original Poster:

979 posts

144 months

Saturday 17th February 2018
quotequote all
Only happend the once after a near rev limit sprint, had a double flash of engine warning light but no feeling of misfire.
As soon as I got home put the OBD2 on the car came up with misfire cylinder 1 & 4
As 1 & 4 fire of the same side of the coil pack I’m thinking either bad connection at the 3 pin plug on the coil pack or 1 side of the coil pack is the issue.
Does this sound right?

stevieturbo

17,229 posts

246 months

Saturday 17th February 2018
quotequote all
If it only happened the once and you felt no problem....clear the code and keep on driving.

if it becomes more frequent then start looking.

PaulKemp

Original Poster:

979 posts

144 months

Saturday 17th February 2018
quotequote all
That’s what I’m going to do
But is my premise right?
I have spare plugs and leads but may buy a spare coil pack as I can use it on a kit car build if not needed

stevieturbo

17,229 posts

246 months

Saturday 17th February 2018
quotequote all
Possibly....but a lot can depend how it determines a misfire.

Is it actually able to distinguish between the two cylinders when it offers a code ? ie it could be any issue on one of those which could be electrical or mechanical.

GreenV8S

30,150 posts

283 months

Saturday 17th February 2018
quotequote all
Seems to me the error code might have been spurious, or it might be indicating a transient fault. If it doesn't come back my view is if it ain't broke don't fix it. Nothing stopping you buying spares ahead of time if you want, but I suggest you avoid the temptation to try speculative fixes for what may not be a problem - it's easy to end up with maintenance induced failure.

PaulKemp

Original Poster:

979 posts

144 months

Saturday 17th February 2018
quotequote all
stevieturbo said:
Possibly....but a lot can depend how it determines a misfire.

Is it actually able to distinguish between the two cylinders when it offers a code ? ie it could be any issue on one of those which could be electrical or mechanical.
Good question, I don’t know that’s why I assumed because it showed 1&4 it was a coil based issue

I just don’t like seeing engine managment lights flash

To add some context this is the first real drive after an engine swap so I am hypersensitive to any thing

PaulKemp

Original Poster:

979 posts

144 months

Saturday 24th March 2018
quotequote all
Problem fixed
Coil pack found to have small crack on the underside and slight swelling from overheating

PaulKemp

Original Poster:

979 posts

144 months

Thursday 19th April 2018
quotequote all
Problem not solved apparently.
New coil pack, plugs, leads and a few weeks later engine light came on, it only seems to happen when I’m giving it the beans and I’m mean near red line stuff and then lift off and hard braking.
The exhaust is a large bore straight through cat back system which pops and burbles, clutching at straws here could that confuse the ecu via the knock sensor which I assume is the only way the ecu can detect cylinder firing.

bearman68

4,642 posts

131 months

Thursday 19th April 2018
quotequote all
ECU doesn't detect misfire through knock sensor (That detects knocks smile). It's done through the crank angle sensor and the acceleration of the crank. (Clever stuff).
Is this a BMW? N43 engine - sounds like the timing chain is on the way out. (clutching at straws)

PaulKemp

Original Poster:

979 posts

144 months

Thursday 19th April 2018
quotequote all
Fiesta ST150 Duratec engine.
I’ll check crank position sensor,distance from 36 tooth wheel and sensor plug.

StoatInACoat

1,352 posts

184 months

Friday 20th April 2018
quotequote all
Are you still getting the same codes? I know on my wiring loom coils 1 and 4 are on a single circuit and 2 and 3 on another. With what you have already done I would swap injectors 1 and 4 with 2 and 3, reset and see what happens. If the same fault comes back I'd be looking at wiring which is the fault I had and it showed itself under similar conditions to yours.

PaulKemp

Original Poster:

979 posts

144 months

Friday 20th April 2018
quotequote all
Thanks for your info, the last few codes over different incidents threw up a P0300 which is multiple cylinder misfire and individual P0303 & P0301.
Will check loom plugs and look at injectors

StoatInACoat

1,352 posts

184 months

Friday 20th April 2018
quotequote all
P0300 makes sense, especially if there is a wiring fault. Start swapping things about to see if the fault moves and see if you can get a wiring diagram for the car.

Just re-read - 01 and 03 suggest that the fault has already moved from cylinders 1-4 to 1-3?

Edited by StoatInACoat on Friday 20th April 12:57