Misfire diagnosis help
03-19-2014, 12:28 PM
#1
Misfire diagnosis help
I am having misfires, not enough to throw a hard code, but have had the shake around 50 mph and TC lockup and drivability issues.
I have the torque app, and running mode 6 / test results I am able to see that cylinder 1 is far and away misfiring the most.
Information:
1. I have new plugs (under 5k mi). Ordered new plug for cyl 1 in the off chance the new plug has a problem.
2. Swapped COP between cyl 1 and 2...no change.
3. Misfires seem to be related to engine rpm. I can get misfires to pile up quickly by holding rpm from 1100-1400 or so. Truck runs uneven, rough, while under light load (1100-1400). If I hold it in this area I can get a misfire to show up (one count) on a few random cylinders, but nearly all on cyl 1.
4. Periodically get the full truck shake when TC locks around 50mph up slight hill.
5. Fuel filter is new.
6. VCT solenoids new. Tech said engine had considerable sludge (looking in solenoid opening).
Bottomline - if this isn't plugs and isn't COPs, what can cause misfires on a single cylinder? My first step is to drop in a new plug for Cyl 1, but this is looking doubtful. Could I have a bad cylinder / compression failure?
Am I correct to assume that MAF/EGR/throttle body and cam/follower/timing would all have either random cylinder misfires or tied to one bank (left or right cylinders)?
I have the torque app, and running mode 6 / test results I am able to see that cylinder 1 is far and away misfiring the most.
Information:
1. I have new plugs (under 5k mi). Ordered new plug for cyl 1 in the off chance the new plug has a problem.
2. Swapped COP between cyl 1 and 2...no change.
3. Misfires seem to be related to engine rpm. I can get misfires to pile up quickly by holding rpm from 1100-1400 or so. Truck runs uneven, rough, while under light load (1100-1400). If I hold it in this area I can get a misfire to show up (one count) on a few random cylinders, but nearly all on cyl 1.
4. Periodically get the full truck shake when TC locks around 50mph up slight hill.
5. Fuel filter is new.
6. VCT solenoids new. Tech said engine had considerable sludge (looking in solenoid opening).
Bottomline - if this isn't plugs and isn't COPs, what can cause misfires on a single cylinder? My first step is to drop in a new plug for Cyl 1, but this is looking doubtful. Could I have a bad cylinder / compression failure?
Am I correct to assume that MAF/EGR/throttle body and cam/follower/timing would all have either random cylinder misfires or tied to one bank (left or right cylinders)?
The following users liked this post:
Ptaaty (03-19-2014)
03-19-2014, 03:14 PM
#3
Mark
iTrader: (1)
and an aftermarket plug
03-19-2014, 04:45 PM
#4
It has the newer style motorcraft plugs, replaced within that last 5k miles.
My next steps are:
1. Replace cyl 1 spark plug (just in case there is an issue).
2. Swap fuel injectors 1-2.
3. Bring it in to shop - get compression test and/or turn it over to shop for troubleshooting.
Seem like the right approach?
My next steps are:
1. Replace cyl 1 spark plug (just in case there is an issue).
2. Swap fuel injectors 1-2.
3. Bring it in to shop - get compression test and/or turn it over to shop for troubleshooting.
Seem like the right approach?
03-20-2014, 10:54 PM
#5
Problem solved!!!
Had the plugs done less than 5k ago but they must have messed up. Plug was loose in cylinder 1, maybe hand tight. Get it out and it was missing the very tip of the electrode.
Put in a new plug (motorcraft of course) now zero misfires.
This forum is a great resource. I had a shake at 50 mph or so with TC lockup, after a rebuilt tranny happened (grr...) I came here and find out it can be a misfire - folks said to look at COPs and plugs.
So I bought a BT OBD2 reader and torque, ran mode 6 (test results) to get individual cylinder misfire data...found that all misfires were on cylinder 1. Swapped COPs between 1 and 2...no change. So checked the plug - bingo!
Had the plugs done less than 5k ago but they must have messed up. Plug was loose in cylinder 1, maybe hand tight. Get it out and it was missing the very tip of the electrode.
Put in a new plug (motorcraft of course) now zero misfires.
This forum is a great resource. I had a shake at 50 mph or so with TC lockup, after a rebuilt tranny happened (grr...) I came here and find out it can be a misfire - folks said to look at COPs and plugs.
So I bought a BT OBD2 reader and torque, ran mode 6 (test results) to get individual cylinder misfire data...found that all misfires were on cylinder 1. Swapped COPs between 1 and 2...no change. So checked the plug - bingo!
03-23-2014, 03:01 PM
#6
Problem solved!!!
Had the plugs done less than 5k ago but they must have messed up. Plug was loose in cylinder 1, maybe hand tight. Get it out and it was missing the very tip of the electrode.
Put in a new plug (motorcraft of course) now zero misfires.
This forum is a great resource. I had a shake at 50 mph or so with TC lockup, after a rebuilt tranny happened (grr...) I came here and find out it can be a misfire - folks said to look at COPs and plugs.
So I bought a BT OBD2 reader and torque, ran mode 6 (test results) to get individual cylinder misfire data...found that all misfires were on cylinder 1. Swapped COPs between 1 and 2...no change. So checked the plug - bingo!
Had the plugs done less than 5k ago but they must have messed up. Plug was loose in cylinder 1, maybe hand tight. Get it out and it was missing the very tip of the electrode.
Put in a new plug (motorcraft of course) now zero misfires.
This forum is a great resource. I had a shake at 50 mph or so with TC lockup, after a rebuilt tranny happened (grr...) I came here and find out it can be a misfire - folks said to look at COPs and plugs.
So I bought a BT OBD2 reader and torque, ran mode 6 (test results) to get individual cylinder misfire data...found that all misfires were on cylinder 1. Swapped COPs between 1 and 2...no change. So checked the plug - bingo!