Cylinder #7

[Adieu]

I'm going to back up to first having problems. About 6 months ago, I drove through a Texas thunderstorm with "torrential" rain. It was bad enough that water was getting on top of my motor even though I was traveling at 85+ mph. My grandson needed me. I am his bestest GRANDMA (Oma). I am mechanically inclined, can rebuild most motors inside of 6 hours with all the parts at my side! Anyway, after this day, I started having numerous problems and was fixing them as they appeared. So, when my OBD II reader showed 3 misfires along with other problems, I fixed all the quick ones and left the misfires for a short time, I changed the front four plugs and was down to 2 misfires #4 & #7 I ordered a complete set of COP's because I had found on the plug change that my COP's in the back were coming apart, literally! When the packs came in, I replaced all 8 plugs, checked the connector gaskets, added dielectric grease to them, I replaced all 8 COP's and reassembled the vents and all the wires, hoses and crap under the hood that makes working on them a PITA! I test drove while running the OBD II coder and received #7 misfire. I believed it may just be build up in the cylinder so I drove it hard for a week. You know like a man, because I have a lead foot! The following weekend, I swapped the coil pack with the one beside it. Misfire stayed on #7. My connectors are tight, no water, no bad COP's, Motorcraft Plugs, just can't get rid of this stupid misfire and my inspection is now past due! So, I will be trying the noid light after my husband brings my car back tonight. He took it to work to test the wiring harness because my meter is missing.

Anything else you may think of...I'm checking aside from asking or stating things that may imply my lack of knowledge like where #7 is located!

PS The bad COP's #7 & #8 the connector (the end that looks like a plug wire, in case you don't think I would know) separated, the spring was stretched and broken on one, and the other was attached to the plug and stretched. Both boots came off the hard plastic body in pieces. I think #7 was dead before the storm and it just didn't throw a code until after. If so, would carbon build up take this long to clean up?

CBU is a mostly a twin turbo thing for newer engines with aggressive EGR....

 

[rexster314]

I had the same thing on my '12 Expy. Symptoms identical. Turns out I had a cracked head. Coolant leaking into cylinder

 

[1955moose]

That's the last resort we hope didn't happen. You might want to pull#7 spark plug, third from front, drivers side, for those of you without a score card. If it was me, I'd pull the fuel pump relay, mines #301, check your owners book which is yours. Run your suv till it dies, pull #7 plug, have an assistant crank key, see if water shoots out of that hole! Im sure theirs tricker ways to check, but if your getting water in there, something should shoot out. I don't need to tell you, wear safety glasses, don't want to get sprayed with water/fuel combo.









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[JZiegler]

I had the same thing on my '12 Expy. Symptoms identical. Turns out I had a cracked head. Coolant leaking into cylinder

I'm not adding any coolant/water to radiator, levels are normal

 

[1955moose]

It's probably not your issue, but with the deluge you went through, might as well eliminate all possibilities of that cylinder,. While the spark plugs out on that bank do a compression test of#7. We've had members in the past do as you with secondary ignition replacement parts, fuel parts, then found out they had a bad valve, or something mechanical that was causing their miss. Exaust all the standard tests first, as any good tech would, then attack internals last.

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[T2p2]

nope my #7 is drivers side and 2nd from the firewall!

Mine is both driver side 3rd from front and driver side 2nd from firewall.
hmmm ...now I have 9 injectors......thats him in the middle

 

[1955moose]

30,000 comedians out of work and Mr Ziegler's auditioning! Well you are close to Los Angeles! Our poor op has been battling his #7 for awhile now. Good or bad He's going to come up with a fix. Guarantee it!

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[1955moose]

My bad its t2p2, who's are in house comic, read it wrong.

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[rjdelp7]

Have you run it low on oil or with wrong viscosity? You may have starved the top end and dislodged a cam follower. That would cause a dead cylinder. A fuel injector problem, can cause a misfire code.