Extreme Cold miss fire ?
 

Putting this in "off topic" as it relates to my 07 Pilot

Really just curious on this....might get long winded here so please forgive me.

About two~three years ago when it was really cold out - remember this is NC - I had a headlight out. Picked one up while out at work. Came home and replaced it, started the car to test it out and the CEL came on :shrug:.

Got my simple code reader out...P0301, humm. Cleared the code and re-started the car and nothing came back. Wrote it off as one of those WTH - never saw another code or any issues (mpg, performance, ect) until.........



Fast forward to yesterday. It has been below freezing for ~4 days, lows in the teens and the highs in the twenties. Went to start the car at lunch time, bam there is the CEL - not flashing, just on. Didn't feel/hear anything strange with the engine but I shut it off anyways. Dug around in the console and glove box and found my code reader.

Sure enough, this time I had multiple codes. 0300 through 0306. We all know Honda isn't real good at pin pointing a single cyl when this happens sometimes. How many times have we read/seen these codes and it turns out to be a single coil/cyl that is the issue.

Cleared the codes, re-started and nothing came back. Drove a short distance and parked it and went back to work. On the drive home, still no issues and made a few stops picking things up on the way home. Remember my drive to and from work is a good mixture of conditions - bumper to bumper all the way to highway cruise.


So if you are still with me......What gives here? Does the car just not like "really cold" temps :shrug:. We got it as an "off lease" trade in - about 3 years old with like 38K on it, it is now ~11 years old with 175~180K - so I have a good knowledge of its history. Regular maint/wear items have been done and are up to date. These are the only two times the CEL has ever come on.

Again, just kind of curious here and wondering if anyone has seen/read something like this before......and if nothing else I haven't started a thread in a while :)

A highly intermittent problem is very difficult to resolve.

Some possibilities to investigate:

1) LTFT may provide an indication of lean or rich drift in a fuel injector but not which one other than bank affected.

2) A frequent problem for the Honda V6's is tightening of exhaust valves to point of missing. Possible early signs of problem in your case. You're at mileage where this problem could arise. I found 2 out-of-spec (not by much) exhaust valves on my son's 03 MDX at 200K miles.

3) Possible failing COP leading to misfire (cyl 1) and misidentification of multiple cylinder misfire. Possibly swap cyl 1 COP to cylinder 4?

good luck

Thanks for the idea's.

1) Didn't think about reading fuel trims on the ride home. I'll have to make a note and watch/read them on the drive to work on Monday.....my cold butt doesn't want to go outside for anything all weekend if I can help it.

2) I did the valve adjustment at 110~120k....so at just shy of 180K I wouldn't think I messed them up that bad :shrug:

3) With a 2+ year gap in getting any code(s), it could be one of the coils just doesn't like the cold.

Performance and MPG have not moved - with my drive style and route, mpg is always in the low 18's to low 19's. I'll worry for a week or so and if nothing comes back, write if off until the time the "issue" decides to grow up and show up more often.

If this only happens in very cold, and then goes away when it warms up then it sounds like an intake manifold gasket problem to me. When it warms up the metal expands and the gasket seals. The colder it gets the metal contracts allowing unmetered cold air into the cylinders. You can spray engine starting fluid or WD-40 around the intake if it throttles up there you go change the intake manifold gasket problem solved. Just be ready incase of fire with an extinguisher handy. And do it when the engine is cold before you start it in the morning. I have done this test MANY times and have NEVER had a fire yet.

Thanks but waiting until it has been less than 20 degrees outside for about a week to try to "catch it" when it decides to ever happen again doesn't sound like my cup of tea.

Again, it has been six months and nothing has come back- of course it is like 90 outside :) , which I like a whole lot better than anything under 40.

Thanks but waiting until it has been less than 20 degrees outside for about a week to try to "catch it" when it decides to ever happen again doesn't sound like my cup of tea. Again, it has been six months and nothing has come back- of course it is like 90 outside :) , which I like a whole lot better than anything under 40.

You do NOT need to wait until it is 20 degrees, You can do it now just do it when you first start it in the morning. True this test is much more effective in the winter when the problem is actively happening but you can still try it right now. Again just spray engine starting fluid or WD-40 around the intake if it throttles up there you go change the intake manifold gasket problem solved.

I have a 2002 Chevy Corvette It did exactly the same thing "only in the winter" it was the intake rubber O rings. I had a Toyota it also did the same thing and it too was the intake O rings. In both cars the problem ONLY reared it's ugly head in the winter and only lasted until the engine warmed up.

The Space shuttle Challenger had the same problem on it's final mission.

How to Diagnose an Intake Manifold Gasket Leak</h1>https://youtu.be/uW3Zw_EH5PU<h1>How to quickly test for vacuum (manifold) leak (All make and model vehicles

Again, since I only see this every 2+ years, I'm not going to worry with it. I've checked fuel trims and see nothing that would lead me to an intake leak. Plus remember, I can't even "feel" the miss the two times in X years it has happened.

I'll keep it in my memory but until something changes - comes back more often, MPG change, fuel trims look "wonky", other potentially related codes come along - I'm not going to worry about it.

Plus, the intake runner set up on the J35 isn't that easy to get to :)