Honda Odyssey Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
97 Posts
Discussion Starter #1
Hi all,

Ody 2001 EX with 245,000 miles on it.
(Not related to this thread, but JUST had to replace the transmission)

I am continually getting rough cold idle/start with error codes P0303, P0305, P0306 (and, of course, P0300)

Things that have been done to address the issue:
  1. I recently had a valve adjustment (March 2020)
  2. I replaced all the spark plugs with NGK 2477 Iridium Spark Plugs (May 2019)
  3. I replaced all the coils (generic from Amazon) (Sept 2018)
  4. Timing belt replaced (March 2015 at 180,000 miles, so 65,000 miles ago)
I also recently did the spark plug extender trick which FINALLY got rid of my P0420 O2 sensor error code (
)

Any thoughts on what I can do to fix this issue? Once the car is warm, it runs smoothly. Recently did a 1,000 mile trip (on the new tranny) and got 24 mpg.

Many thanks!
 

·
Registered
Joined
·
826 Posts
Generic from Amazon coils may not work as well as OEM Hitachi.
With this generation, you can't always trust the misfire code for being at that cylinder.
Did you do a coil drop test? That's how I diagnosed my misfire, replacing one coil fixed my misfire.
With the engine running, pull the coil off of the spark plug. If the idle is worse, that's not the problem coil. If the idle is unaffected then you found the bad coil. Went to my u-pull yard and got a replacement out of one a generation matching mine. (Also pulled a spare) In the lot quickly swapped in the new coil, problem gone! I also tested my spare so I could get an exchange if it was bad.
Do a drop test to verify that your coils are not the problem.
Good fix with the extender on the cat.?
 

·
Registered
Joined
·
679 Posts
If by chance you saved your original coils, Put them back on and see of that clears the problem. (Assuming they were all working, and you were just being proactive, when you replace them all).
 

·
Registered
Joined
·
12,037 Posts
Any smoke on initial start up when it's running rough? White smoke would indicate coolant in the cylinders and blue smoke would indicate oil in the cylinders. If it was me, I'd start it cold, see if it runs rough. If it does, shut it off right away and pull the plugs. See what they look like.
 

·
Registered
Joined
·
97 Posts
Discussion Starter #5
If by chance you saved your original coils, Put them back on and see of that clears the problem. (Assuming they were all working, and you were just being proactive, when you replace them all).
Interestingly, I did save the originals. I wasn't sure they were actually the problem. I will put them back in.
 

·
Registered
Joined
·
826 Posts
Very interesting how some problems spring up in multiple posts around the same time. Check out this post- P0300-306,P1399,EGR uncommon fix
If it hasn't been looked at, the EGR passages on the top of the engine may need to be cleaned out. Or more likely, will need to be cleaned out in any case!
 

·
Registered
Joined
·
97 Posts
Discussion Starter #7
Very interesting how some problems spring up in multiple posts around the same time. Check out this post- P0300-306,P1399,EGR uncommon fix
If it hasn't been looked at, the EGR passages on the top of the engine may need to be cleaned out. Or more likely, will need to be cleaned out in any case!
I should have mentioned that I have cleaned out the EGR passages twice, and replaced the EGR valve as well. The suggested post was interesting, and I did disconnect the EGR and noticed no differences.
 

·
Registered
Joined
·
97 Posts
Discussion Starter #8
Interestingly, I did save the originals. I wasn't sure they were actually the problem. I will put them back in.
Well, well, well. I unplugged each coil in turn (just the front bank) and noticed that the middle one made almost no difference at all. I reinstalled my old Hitachi coil, and it seems like the engine is running smoother! I usually reset the codes, but didn't bother this time, and then just cleared out themselves after a couple of runs.
 

·
Registered
Joined
·
826 Posts
Well, well, well. I unplugged each coil in turn (just the front bank) and noticed that the middle one made almost no difference at all. I reinstalled my old Hitachi coil
Great! You basically did a coil-drop test and found the bad coil!
Good to hear you're familiar with the EGR passages clogging, and that wasn't the problem.
 

·
Registered
Joined
·
97 Posts
Discussion Starter #10
Any smoke on initial start up when it's running rough? White smoke would indicate coolant in the cylinders and blue smoke would indicate oil in the cylinders. If it was me, I'd start it cold, see if it runs rough. If it does, shut it off right away and pull the plugs. See what they look like.
Thanks for the suggestion John. No smoke at all on startup.
 

·
Registered
Joined
·
679 Posts
I remember reading many posts. Owners, install "generic" coils. They work fine for a while, (year or so), then "act" up.
You can keep your "old" ones, and replace your "generic" ones when they fail. Or bit the bullet, and buy OEM's,
Anyway, glad you have the solution. (y)
 

·
Registered
Joined
·
3,030 Posts
Well, well, well. I unplugged each coil in turn (just the front bank) and noticed that the middle one made almost no difference at all. I reinstalled my old Hitachi coil, and it seems like the engine is running smoother! I usually reset the codes, but didn't bother this time, and then just cleared out themselves after a couple of runs.
The middle spark plug in front , cyl 5, is known to be one plug that has gotten loose on it;s own. Mine did.
Next time you remove that ignition coil, check that plug for tightness.
Buffalo4
 
1 - 14 of 14 Posts
Top