Persistent #8 misfire, 01 Navigator

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Fordgirl01

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Last December I picked up a 01 Navigator from Arizona. For me it was quite a find (even with its issues) living in northern NY where vehicles rust very quickly. I just washed it off and parked it for the winter. With spring and warmer weather hopefully arriving here one of these days, I am thinking about getting to work on this 01 soon. Of course I am looking for the excellent advice that I always receive here! The person I got it from got hit with a pretty hefty repair bill from the dealer and it still did not fix it. I’m sure they gave her a horror story (they told her it needed a new motor) and sold her a different vehicle. Maybe their diagnosis is accurate, but I always question info from a dealership repair shop as they are in the business to sell vehicles. I got some service records with this vehicle so I will post the history that I know:

6/18/18. Passed Arizona inspection: 111,785 miles (a guy in the military owned it and that is how it made it up here)

6/29/18. Davidson Auto Group
Front end alignment, repaired chafed wire on starter solenoid: 113,205 miles

8/2/18. Davidson Auto Group
new owner said engine light was on steady since she purchased vehicle but never flashed.
Mileage: 114,000
Complaints: low idle, stalls, shudders between 40-50 MPH during acceleration.
TESTS:
Power balance-dead skip on 5,7,8
Injectors tested OK
Ignition system test-coil fail on 5,7,8
Repairs: replaced coils and plugs on bank 2 (5,6,7,8), noted #8 spark plug had burnt electrodes.
Test drove - #8 still had dead skip
“Due to cylinder being washed down from lack of spark which resulted in low compression. Need to remove cylinder head from bank 2 to inspect engine.”

One of my friends who has his own shop told me to check the cats. So it makes me wonder if the vehicle has been driven with the misfires, could it have damaged the cats? Also-I put my scanner on it when I got it and it is showing misfire on 8 and now 3, lean bank 1 and lean bank 2. The guys that delivered it to me said when they let off the throttle, the engine skip stops and the SES light goes off.

Thoughts??!



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1955moose

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The lean running codes can be bad catalytic converters. As we've posted here, concentrate on those 2 cylinders for now. #3 is a new code, so you'll want to replace that coil with one next to it, see if miss fire moves. After that I'd get a smoker, and see where the smoke comes out from in the intake. I also like taking old school compression tests of those suspect cylinders. If you've got a bad valve or 2, you can be chasing your miss till Christmas. After you get a handle on the miss, run it by an exaust shop and let them check the back pressure of the 4 cats. Are you doing the work yourself? Report what you find, we'll get you through it.

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Fordgirl01

Fordgirl01

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The lean running codes can be bad catalytic converters. As we've posted here, concentrate on those 2 cylinders for now. #3 is a new code, so you'll want to replace that coil with one next to it, see if miss fire moves. After that I'd get a smoker, and see where the smoke comes out from in the intake. I also like taking old school compression tests of those suspect cylinders. If you've got a bad valve or 2, you can be chasing your miss till Christmas. After you get a handle on the miss, run it by an exaust shop and let them check the back pressure of the 4 cats. Are you doing the work yourself? Report what you find, we'll get you through it.

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Yes I will be doing the work myself unless it’s something I feel is wayyyy beyond my ability!! I know you will get me through it! I won’t be starting in it for a bit but I will surely take suggestions and report back when I get into it. They did do a compression test at the dealer but I’m not certain if it was before or after the coil/plug replacement. It shows 0% for 3,2,6,5,4. 4% for 1, 5% for 7 and 36% for 8 (I’m assuming that’s bad)!! Mean cranking RPM 168.


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1955moose

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Those readings make sense. Your SUV wouldn't even run. Either get a scanner that can read cylinder compression/balance, or pull fuse for ignition, or crank position sensor, so it won't start, and do all 8 old school, with a screw in gauge. Looks like #8 is leaking causing your miss. Would explain why the miss in #8 doesn't go away.

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Fordgirl01

Fordgirl01

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Those readings make sense. Your SUV wouldn't even run. Either get a scanner that can read cylinder compression/balance, or pull fuse for ignition, or crank position sensor, so it won't start, and do all 8 old school, with a screw in gauge. Looks like #8 is leaking causing your miss. Would explain why the miss in #8 doesn't go away.

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I do plan on getting a screw in gauge to test it myself. So what I find odd is...#1, it runs and #2, the SES light does not flash. My 99 Navigator flashes not long after it trips the light when it misfires. I replace the coil and it’s good to go! I would think the light would be flashing. Well you’ve given me some great places to start. I will get a gauge and plan on testing #8 first (after I look at the coils to make sure they really did replace them)!

Thank you and I’ll keep you posted!


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1955moose

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The fact that 3 coils in a row needed replacement says someone tried to give your overweight baby a bath, and didn't cover the coils. Shorts em out every time. If you get a low reading on #8, squirt a little oil into that hole, let it sit about 1/2 hour, do test again. If it goes up, rings, if not, a valve.

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Fordgirl01

Fordgirl01

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The fact that 3 coils in a row needed replacement says someone tried to give your overweight baby a bath, and didn't cover the coils. Shorts em out every time. If you get a low reading on #8, squirt a little oil into that hole, let it sit about 1/2 hour, do test again. If it goes up, rings, if not, a valve.

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I will definitely put your advise to good use. It’s winter here again now so my overweight baby is still parked in a snowbank waiting for warmer weather! I will keep you updated when I get into it. Thanks again.


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1955moose

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If concentrating on that #8 doesn't yield results, you might want to pull the driver's side valve cover. We've got another member that had a similar situation, and found a broken valve spring. Hopefully yours is simple, but life rarely is.

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Fordgirl01

Fordgirl01

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If concentrating on that #8 doesn't yield results, you might want to pull the driver's side valve cover. We've got another member that had a similar situation, and found a broken valve spring. Hopefully yours is simple, but life rarely is.

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I think the fact that I have to deal with #8 immediately makes it not simple! So far I have only changed plugs and coils on #5-lucky break-2 different vehicles and both the easiest ones to get to. Any tips of tricks for reaching the more difficult ones (like #8)? It looks like I’ll have to remove several things to get to it. The good news is they were just replaced (supposedly) on that side, so it shouldn’t be hard to get out once I get at it.


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1955moose

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Items have to be moved aside. Also you'll need a 7mm flex 1/4 inch drive socket to get off/on the bolt that holds down the coil. A sparkplug socket that has locking extensions helps. A hunk of hose that fits snug over new sparkplug to start into threads helps a bit. No one said this is going to be easy! But once you figure it out, it's not that bad the next time you have to change those back 2 on both sides. Lots of videos online to show you how. You can do it!

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