iPwn

I'm running into a bit of an annoying problem with my 2002 LX (380 k) showing the following misfire codes:

P0300
P0302
P0303

P0300 and 03 don't happen very often, once in a while. The 02 comes up daily, I really have no idea what could be causing it apart from either a faulty sensor or wiring maybe?

Anyway, I've tried the following to no avail and was hoping for some insight:

- Compression test on all 4 cylinders, all came at 150 psi +
- Inspected and changed spark plugs, Cylinder 2 did have some carbon build up, but nothing significant (Still came up with P0302 after being replaced)
- There is no oil leakage on the spark plugs when they were replaced
- Tried fuel injector cleaner on 3 full tanks in a row, maybe I need to do a couple more?

iPwn

just wanted to add, that I've also rotated the Coils around on Cylinder 2 with Cylinder 4 to see if the problem follows it, but no dice.

ezone

Got freeze frame data?

Does this engine have an EGR valve?

iPwn

Can you elaborate on that? i use Torque to read my codes through a blue tooth OBDII reader.

Yes it does

Brandon@fattysmotorsports

Sounds like a ignition issue. Does it only misfire at idle or all throughout the rmp range?

ezone

Freeze Frame Data is a set of parameters recorded by the PCM at the moment the fault code set.

It would have info about RPM, VSS, ECT, Fuel trims, Calculated Load, MAP, and more. Sometimes a whole lot more, depending one the scanner, the car, year, and code.

I can tell more about what was going on with the engine at the time the code set that way. FF data can give me far more info than the owner/driver can.

Example: A lean code that sets while driving down the road may have a completely different cause than a lean code that sets at idle.
Ditto for misfires.




If the code set while driving at a steady(ish) speed, maybe 30-60MPH, warmed up engine........
I'm thinking the intake probably need pulled off to clean out the EGR passages.

iPwn

it happens at all ranges, when I'm driving on the highway, or cruising, or stopped... that's another bit of the frustration - there's no consistency.

well there is, it happens every time I drive it lol

iPwn

I'll see if I can get that, I dont know if Torque is capable of doing that... wish me luck!

ezone

Are you just saying the check engine light is on under all those conditions?

Or are you saying you can feel it misfire under all those conditions? Can you even feel it at all when it misfires?


------------------------------------

Have you checked valve adjustment lately?
When was the last head gasket done?
Is it losing any coolant?

Compression test? I know you said 150+, but be more exact.
I expect 180+ out of these, and one with 150 would be a problem. Also, I keep on cranking it until the gauge is positively maxed out, then let it hit a few more times just to make sure.

iPwn

I have not checked the valve adjustment, the last head gasket was changed about 60k ago, and there is no coolant being lost.

I cranked it for about 5-6 turns, I dont think i maxed it out, but I can redo that as well.

I generally clear the code, and I will witness the light flash while im driving into a solid, the odd time I will feel the car lag even jerk slightly when it comes on - I read the code and it's always a P0302 (Misfire in Cylinder 2) with P0300/p0303 once and a while. The car has a pretty rough idle as well (a noticeable shudder).

ezone

Ok just for laughs, disconnect the wire connector from the EGR valve and drive it for a day or two, or however long enough it takes just to see if the misfire codes go away.
(It will still set new codes because the valve is unplugged though.)

This could eliminate at least one possible cause for the moment.

iPwn

I've disconnected the egr, reset the faults.. Very little laughter during the process but I'll let you know how it goes after a day or 2.

I may go ahead and clean it as well if it's dirty.

ezone

When the head gasket was done last, did the EGR passages get cleaned out at that time? Seems like it takes quite a bit of mileage to accumulate enough buildup to cause misfire code problems.

iPwn

I don't believe so, I bought this car used last year as a beater, he changed the timing belt and gaskets.

Just an update, 2 days without the egr plugged in and no 302 code yet. I've done maybe 50-70 km, and it would usually have shown up by now.

I also wanted to note, I didn't think this was related; my car would make a rattle snake like noise in short bursts under load (going from say 1st to 2nd). I didn't think much of it thought it was an engine mount. But that has now disappeared.

But yeah no more 300/2/3

ezone

Pull the intake manifold. The cylinders that DIDN'T set misfire codes are the ones you will find clogged....but clean all of them.


Here's an epic thread, the fix comes in around the last page IIRC
https://www.civicforums.com/forums/36-mechanical-problems-vehicle-issues-fix-forum/345718-2003-ex-misfire-p0300-p0301-p0303-p0304.html
Probably related, due to unequal EGR distribution.

iPwn

Thank you sir for your help, I appreciate it

ezone

Wait until you are satisfied that the misfire codes should have shown up, then attack it.....

You will find the EGR channels in the distribution plate (fuel injector manifold) PACKED with carbon, and a bunch of carbon in the sides of the intake ports. It all needs to be removed, scraped somewhat clean. Doesn't have to be shiny or anything, but get all the deposits out.

Screwdrivers, scraper, and a shop-vac with a small tube taped to the nozzle to suck out the loose stuff?

I reuse gaskets without a problem. We never have any on hand when I need them.

iPwn

Beauty; I'll give this a whirl this weekend when I have a chance - basically what I've read to do is scrape it out as you had mentioned.