Still throwing code #P0304 cylinder 4 misfire
#1
Still throwing code #P0304 cylinder 4 misfire
OK gang, I've tried everything i can think of here and I am still throwing the code P0304. Cylinder #4 misfire detected. Thus far to correct this issue I have replaced the cap, plugs, rotor, and wires. I have installed headers with gaskets. I have installed spark plug wire seperators to keep the wires well apart.
Lastly I have done a compression test. on the first round the compression tested as follows for each cylinder:
#1: 155 PSI
#2: 155 PSI
#3: 145 PSI
#4: 135 PSI
#5: 145 PSI
#6: 150 PSI
#7: 145 PSI
#8: 155 PSI
So the left bank is reading:
#1: 155 PSI
#3: 145 PSI
#5: 145 PSI
#7: 145 PSI
So the left bank seems to be within spec as the book says the minimum is 100 PSI and acceptable drop between adjoining cylinders being a Max of 40 PSI. so with only a 10PSI drop between #1 and the rest I think i'm ok here.
The right bank read is a little less desireable but well within specs according to the book with numbers reading:
#2: 155 PSI
#4: 135 PSI
#6: 150 PSI
#8: 155 PSI
so the right bank has a more noticable difference between cylinders and the #4, the cylinder throwing the code, has the lowest pressure of the lot. Its still only a 20 PSI drop or 15 PSI drop from the cylinders to either side.
So I focused on the #4. following the books instruction I squirted 3 blasts of oil into the #4 cylinder and ran the test again. this time the cylinder read at 155 PSI. According to the book that indicates worn rings on that cylinder. I am of course hesitant to tear the engine down to replace the rings on just one cylinder obviously. But do you think the rings could be whats throwing the code? Or is there something else I should be looking at here?
btw its the 5.2L V8 on a 98 1500 with the 46RE and 2Wd
Lastly I have done a compression test. on the first round the compression tested as follows for each cylinder:
#1: 155 PSI
#2: 155 PSI
#3: 145 PSI
#4: 135 PSI
#5: 145 PSI
#6: 150 PSI
#7: 145 PSI
#8: 155 PSI
So the left bank is reading:
#1: 155 PSI
#3: 145 PSI
#5: 145 PSI
#7: 145 PSI
So the left bank seems to be within spec as the book says the minimum is 100 PSI and acceptable drop between adjoining cylinders being a Max of 40 PSI. so with only a 10PSI drop between #1 and the rest I think i'm ok here.
The right bank read is a little less desireable but well within specs according to the book with numbers reading:
#2: 155 PSI
#4: 135 PSI
#6: 150 PSI
#8: 155 PSI
so the right bank has a more noticable difference between cylinders and the #4, the cylinder throwing the code, has the lowest pressure of the lot. Its still only a 20 PSI drop or 15 PSI drop from the cylinders to either side.
So I focused on the #4. following the books instruction I squirted 3 blasts of oil into the #4 cylinder and ran the test again. this time the cylinder read at 155 PSI. According to the book that indicates worn rings on that cylinder. I am of course hesitant to tear the engine down to replace the rings on just one cylinder obviously. But do you think the rings could be whats throwing the code? Or is there something else I should be looking at here?
btw its the 5.2L V8 on a 98 1500 with the 46RE and 2Wd
#2
#3
RE: Still throwing code #P0304 cylinder 4 misfire
I'm not afraid to do a tear down. I'm fairly mechanically inclined and have a host of tools to do the job. It just seems like an awful lot of work to replace one cylinders rings if thats not the actual cause of the issue, not to mention the down time.
#4
#5