scattermaster
Member
I've been chasing this #8 misfire for a while now. I also had lean codes for both banks.
So far I've:
1. installed a new intake manifold.
2. Installed a new PCV valve and hose assembly.
3. Cleaned and tested all 8 injectors. All look good. Moved #8 to #1 position.
3. installed new spark plugs. (#8 twice, + a new COP)
5. inspected all the vacuum lines that I can see. Checked with a gauge at idle and it's pulling about 18hg.(IIRC)
After about 400 miles, there are no more lead codes but I still have a pending #8 misfire and the catalyst and evap will not complete.
I checked fuel trims and I don't remember what the numbers were but it didn't seem like the computer was having to make real drastic corrections. I will say that the 2 banks have different amounts of correction. O2 sensors are responding normally.
I did a compression test today. (cold) All cylinders top out at about 200 psi. About 180 psi at 5 cranks.
I tested all the injector plugs with a NOID light and all 8 look good.
I noticed today that the ceramic near the electrode on the #8 spark plug was white. All the other ones were slightly tan.
I want to do a spark test but it's difficult to rig. When it's installed it's too tall for the coil wire/plug to reach. It's one of the ones with the light. I'm not sure how I'm going to make it happen.
Does anyone have any advice on how to rig the spark test?
thx,
Jim
EDIT:
I took a long piece of #10 wire and attached one end to a bolt on the engine. I attached the other end to the side of a plug. Then used one of the COP's with the that plug inserted and plugged it into the #1 COP connecter and hit the key.
It sparks. Then I moved to the #8 cylinder and did the same thing and got the same spark.
So, it seems to me that I have spark, fuel, compression, and air.
And a misfire...
I'm all out of things that I know to do except put it all back together and see if it went away.
Am I missing something?
Jim
So far I've:
1. installed a new intake manifold.
2. Installed a new PCV valve and hose assembly.
3. Cleaned and tested all 8 injectors. All look good. Moved #8 to #1 position.
3. installed new spark plugs. (#8 twice, + a new COP)
5. inspected all the vacuum lines that I can see. Checked with a gauge at idle and it's pulling about 18hg.(IIRC)
After about 400 miles, there are no more lead codes but I still have a pending #8 misfire and the catalyst and evap will not complete.
I checked fuel trims and I don't remember what the numbers were but it didn't seem like the computer was having to make real drastic corrections. I will say that the 2 banks have different amounts of correction. O2 sensors are responding normally.
I did a compression test today. (cold) All cylinders top out at about 200 psi. About 180 psi at 5 cranks.
I tested all the injector plugs with a NOID light and all 8 look good.
I noticed today that the ceramic near the electrode on the #8 spark plug was white. All the other ones were slightly tan.
I want to do a spark test but it's difficult to rig. When it's installed it's too tall for the coil wire/plug to reach. It's one of the ones with the light. I'm not sure how I'm going to make it happen.
Does anyone have any advice on how to rig the spark test?
thx,
Jim
EDIT:
I took a long piece of #10 wire and attached one end to a bolt on the engine. I attached the other end to the side of a plug. Then used one of the COP's with the that plug inserted and plugged it into the #1 COP connecter and hit the key.
It sparks. Then I moved to the #8 cylinder and did the same thing and got the same spark.
So, it seems to me that I have spark, fuel, compression, and air.
And a misfire...
I'm all out of things that I know to do except put it all back together and see if it went away.
Am I missing something?
Jim
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