5.4 V8 Misfiring AGAIN!
2 still fires and I don't think I've ever had an issue with cylinder 2 misfiring. Oddly enough it always came up as cyl 8 misfiring, along with 4. 8 seems fine pressure wise.
Anyone have a link from here how to tear into this and get them (rings) replaced?
Anyone have a link from here how to tear into this and get them (rings) replaced?
Compression Test—Interpreting Compression Readings
Did you oil test it your low readings ? If one or more cylinders reads low, squirt approximately one tablespoon of clean engine oil meeting Ford specification on top of the pistons in the low-reading cylinders. Repeat the compression pressure check on these cylinders.
1. If compression improves considerably, piston rings are damaged.
2. If compression does not improve, valves are sticking or seating improperly.
3. If two adjacent cylinders indicate low compression pressures and squirting oil on piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil and/or coolant in cylinders could result from this condition.
Also, use the Compression Pressure Limit Chart in my sig if you want or if you don't have one. Keep in mind when checking cylinder compression, the lowest reading SHOULD be within 75 percent of the highest reading.
Your numbers are all over the place lol. I'd check it again following procedure and add in a shot of oil when getting a low reading to confirm where the problem is. IMO, it's hurt, but reconfirming might help you decide whether or not a new/used motor would be in order.
I had my wife in the drivers seat with the gas peddle on the floor and turning it over for me while I counted 5 turn overs then stopped.
So far on cyl 2 & 3 testing with oil resulted this:
2: without oil was 97psi with oil 130 psi
3: without oil was 135psi with oil 150psi
I was using that link in your sig as a guide, and my numbers are all over the place.
So far on cyl 2 & 3 testing with oil resulted this:
2: without oil was 97psi with oil 130 psi
3: without oil was 135psi with oil 150psi
I was using that link in your sig as a guide, and my numbers are all over the place.
I had my wife in the drivers seat with the gas peddle on the floor and turning it over for me while I counted 5 turn overs then stopped.
So far on cyl 2 & 3 testing with oil resulted this:
2: without oil was 97psi with oil 130 psi
3: without oil was 135psi with oil 150psi
I was using that link in your sig as a guide, and my numbers are all over the place.
So far on cyl 2 & 3 testing with oil resulted this:
2: without oil was 97psi with oil 130 psi
3: without oil was 135psi with oil 150psi
I was using that link in your sig as a guide, and my numbers are all over the place.
Yea, I would re-soak for each comparison test (adjacent only). Just because oil can eventually leach back into the pan. How fast depends on ring condition and piston/stroke position. So,depending upon where the piston is, oil may leach faster. These engines tend to have a little piston slap @ #1 and #2 cylinders, it's common and generally not a problem, but if the piston is positioned opposite of TDC, it will leach faster. So, to perfect testing a re-soak of adjacent would be in order.
Time consuming and a hassle, but worth the effort IMO.
Time consuming and a hassle, but worth the effort IMO.
And here's the results:
Cyl 1 was 195psi with oil is 230psi
Cyl 2 was 97psi, 1st oil test was 130psi now it's 180psi
Cyl 3 was 135psi 1st oil test was 150psi now it's 200psi
Cyl 4 was 95 psi with oil is 150psi
What do you think?
Cyl 1 was 195psi with oil is 230psi
Cyl 2 was 97psi, 1st oil test was 130psi now it's 180psi
Cyl 3 was 135psi 1st oil test was 150psi now it's 200psi
Cyl 4 was 95 psi with oil is 150psi
What do you think?
Think you misunderstood, - just oil in the low compression cylinders as the write up suggests. Test adjacent to see if #'s change. No oil in adjacent tho. This test verifies the gasket condition.
Now I understand, test the cylinders next to the low psi ones after putting oil in them but not putting oil into them.
Well sadly I misread and put oil in all 4 of them to test,so now what? Do I wait a while and test them again?
Well sadly I misread and put oil in all 4 of them to test,so now what? Do I wait a while and test them again?





