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Originally Posted by Random1,Aug 25 2005, 11:36 PM
The car now has just over 53k miles (was 48k when the original problem started) and the rough idle came back in cylinder #1 about a month ago.
I'm curious what your original set of injectors look like (the area sticking into the manifold) when you took them out of mission. From what I read, I tend to agree that you seem to somehow have too much oil going into the intake and fouled the injector spray pattern. I've never seen so much gunk build-up on the injectors even after 100k miles (on other cars).
Originally Posted by Race Miata,Dec 5 2005, 07:26 PM
I'm curious what your original set of injectors look like (the area sticking into the manifold) when you took them out of mission. From what I read, I tend to agree that you seem to somehow have too much oil going into the intake and fouled the injector spray pattern. I've never seen so much gunk build-up on the injectors even after 100k miles (on other cars).
There is one picture near the top of the second page of this thread that shows the tip of one of the injectors. The tips looked perfectly clean.
Maybe the oil build up was from the PCV. You'd be amazed at how much oil goes through there when you run the engine hard. I also had multiple incidents at autocross on right hand sweepers where oil came through and lots of white smoke was created out the exhaust. Since then I have added an oil catch can, that's where you can see how the oil builds up. With catch can most of the oil is trapped before entering the manifold.
I have the symptoms as yours, but I seem to have cured it with the simple "MAP whack":
1) Two months ago, driving about 35 mph in town the CEL came on. Pulled into the parking lot, looked over the engine, wiggled the MAP sensor connector, and see nothing wrong. Go to Autozone and pulled the code:
P0302 - Cylinder 2 misfire.
After a few more engine start/stop cycles, CEL disappeared.
2) Today, driving about 40 mph in town CEL came on again. Pulled the following CEL codes this time:
P0301 - Cylinder 1 misfire.
P0302 - Cylinder 2 misfire.
P0300 - Random misfires
P1399 - Honda misfire code?
Did the full MAP whack (with anger!) and ECU reset this time, and suddenly the idle is as SMOOTH as it has ever been! I actually was never aware how lumpy the idle has been previously - I assumed that was how it was supposed to be.
Never overrevved, but lives in VTEC a few days of the year. I hope the fix is permanent.
Fellow drivers... especially trackers...
I notice that oil mist enters the combustion chambers from two places.
One, is the breather hose from the valve cover to before the throttle body. The second is from the PCV valve post-throttle body.
To eliminate the first, I plugged the breather inlet at the intake and installed a dedicated, filtered breather complete with a one-way valve (modified PCV valve). This way, the PCV sucks in air that is restricted, causes a slight negative pressure under the valve cover, and does not introduce oil mist at the throttle body. The throttle body has a small air bypass that can get dirty through oil mist and cause rough idle.
Lastly, for hard-driving track events, I have an oil catch-can installed between the PCV valve and the inlet manifold.
With the two mods, I am able to keep about -3BAR of pressure inside the valve cover and very little, if any, oil mist makes its way to the combustion chambers.
Drive on.
...and one more thing...
I just saw the pictures of the fouled injectors.
It's plausable that oil mist may cause such a condition, but mainly I am curious about the gasoline.
What gasoline do you use? From what vendor?
Me, I loyally stay with Chevron, and ocassionally, Exxon supreme.
What do you run with?
Here's what I have...
Note the dedicated filtered breather. AutoZone, $6. Plus there is a pcv valve with flow directed toward the filter, so flow is restricted in to the valve cover. I also drilled a tiny bypass hole in the pcv valve because negative pressures were exceedingly high. (I thought)
Modified gas filter. A bit restrictive, but it worked. Have it installed between the PCV valve of the valve cover and inlet manifold. Less than $6.
This setup seems to work.
Originally, I crafted this setup to fix two problems. Negative pressure for dipstick pop-up, and oil mist elimation under max performance conditions.
The dipstick popup was subesequently solved by replacing the o-rings and turning the dipstick handle 180 degrees - which provides enough lateral seating to keep it in place.
Sorry...
I left out the photo with the modified breather with the installed PCV valve for one-way breathing.
Here's what I have today for street driving.
I install the oil-catch can for HPDEs...
Note the PCV valve between the breather filter and valve cover.
11-29-2005, 08:32 PM
