'new' engine, misfire on cyl 8

[nerdwrench87]

so I got a used, low mileage motor installed, and overall runs great. however, yesterday I hosed it down because it was filthy. it started throwing a P0308 - misfire on cyl 8.

I figured it was from the water in the cylinder, as that is something I'm used to.

I heated it up nice and good and drove it around for awhile, since I don't have a compressor to blow the water out. I cleared the code, and all seemed well.

I drove it to work this morning, and going up a hill, I put my foot into it, maybe 3/4 throttle, and it starts bucking and the check engine light starts flashing. I am willing to bet it is the same code, I can pull it once I get on break.

if it is the same cylinder, could it be from water, or does it sound like the motor has something wrong with it, and I should take it back under warranty?

*note* the expy is a 2001, and the motor is from a 2004, with 82,000 miles on it. Aside from the year difference, is there a huge difference between those years? the shop also claims they did a tune up, coolant, and T-stat. anything in particular I should check out?

 

[1997SCEBFEX]

my bet would be water for sure.

the rear "T" for the rear coolant to the core back aft, if you have that, is notorious for leaking after moving things around, or not drying off properly etc. from disconnection to get to 7 & 8 plugs.

personally, these things don't like direct water/fluids on them aside from what you'd get driving.

hope you get it figured out and report back.

 

[nerdwrench87]

I just checked on break, and sure enough...P0308 is back. It is stumbling pretty good. I'm not sure about the rear T for the rear coolant... I know it has rear heating and cooling, but I have never actually used either outside of testing in the 14 years the truck has been in the family. the rear heat kind of works, but the rear a/c doesn't. I figured it was a blend door and never messed with it.

so these have another Tstat in the rear of the motor, huh? interesting!

I'll spray WD-40 and then blow it out with canned air when I get home.

 

[1955moose]

Now you know why you don't wash these motors! Your describing a shorted coil, or connection to it. A sharp on/ off bucking is electrical. Pull the connector to #8 coil, blow it out, use a smear of die electric grease, and should come back. If not swap the coil next to it, or better still if you have your old motor, grab one of those coils. In the future, wrap plastic bags around coils, and any electrical items if your going to hose down.

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[nerdwrench87]

Yeah, I guess I know that. Hopefully I didn't fry the COP. That number 8 is a PITA to get to come out to play. I lost my wigglies, so I am not looking forward to taking out the COP.

 

[nerdwrench87]

so I have not had time to pull the coil pack... I can do that on Thursday. (finals week). However, when its cold, it runs good.... until you jump on the gas. then it starts misfiring on cylinder 8.

yet it had a momentary good spell, and full throttle did not trigger the engine light, and I was doing 95 before I realized it.

sure seems to be more of a coil pack issue than a bent valve or something. and I knew better than to wash it down, my Hyundai doesn't like water either. *sigh*

 

[Bedrck47]

my bet would be water for sure.

the rear "T" for the rear coolant to the core back aft, if you have that, is notorious for leaking after moving things around, or not drying off properly etc. from disconnection to get to 7 & 8 plugs.

personally, these things don't like direct water/fluids on them aside from what you'd get driving.

hope you get it figured out and report back.

Isn't the rear "T" on the passenger side? Plugs #3 & #4
OP states P0308 That would be the back plug Drivers Side

I would check the wiring to the coil Also may be a bad boot on Plug #8

However Would agree that water and these engines don't mix

 

[1955moose]

Well if you were wondering the sex of your Suv, now you know it's a boy! Boys never like to take baths!

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[Bedrck47]

Well if you were wondering the sex of your Suv, now you know it's a boy! Boys never like to take baths!

Sent from my N9131 using Tapatalk

Is that from EXPERIENCE????

 

[docraymund]

No choice you have to pull the coil and plug out to examine and test them. If both are ok then check the electrical connectors for looseness -just slightly bend the tabs for a tighter fit.

 

[rjdelp7]

Swap coil to a new location. It new code is set, you found your problem. Beware: driving on a misfire will kill your Catalytic Converter(s). Disconnect the fuel injector on misfiring cylinder, if you are forced to drive it.

 

[1955moose]

When I was young, less than 11, baths were an option. Then I discovered girls, and took one everyday! Today its showers everyday! After getting dirty working on a car/truck all-day, nothing feels better than that hot shower!

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[nerdwrench87]

okay, so I pulled the plug and the coil pack. I replaced the coil pack on general principles, along with both front wheel bearings. plastic pos's were all messed up - luckily they didn't grenade and my races were fine.

so now with a new coil pack on #8 , it purrs like a kitten and you cannot even tell it is running.

and the vibration from the wheel bearings is gone.

now im preparing for the rest of the coil packs to go bad, since I replaced one.

 

[1955moose]

Actually if you didn't get them wet, you'll probably be OK. Water or coolant seems to be about the only thing that shorts them out. If you hose off again, please cover everything in plastic! Or better still clean by hand with rags and cleaners like simple green.

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[nerdwrench87]

Yeah I learned my lesson with that one lol.

Now the negative battery terminal broke.

Man.. I’m having bad terminal luck lately.

 

[1955moose]

Bad luck comes in threes, then done. Between the coil, the bearings, and now the battery cable, your done! Positive things from here.

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[nerdwrench87]

Hopefully the gas mileage will settle down a bit. I topped it off yesterday and it went from full to 3/4.... in 45 miles. Almost all freeway.

I’m gonna gather a look at the pcv and iat once I do the terminal, clean the MAF, and if all else fails I’ll hook up the Solus to it and get the live graphs

 

[Andy J]

While your at it, yank the front plug on the drivers and pass side and see if they look new. If they do, yank number 4 and see if it looks new. Alot of shops will do a shoddy tune up and only do the plugs that are easy to get to. When u have the front 2 plugs out, look at the boots. If they look brown, flared out on the ends, or feel sticky you should change them. If u need new ones autozone had a full kit with 8 boots and springs. If i recall its duralast part number 90003. If you do.replace the boots, get a tube of dielectric grease like what was mentioned earlier, and put a glob on the end that goes on top of the plug, and smear some around the little sealing ring on the boost about an inch below where it pushes onto the coil. Also, if you are going to replace the springs, use a pair of gloves and yank them off the bottom of the coil. Check the terminal where thr spring pushes onto. If theres any green stuff or corrosion, get a small flathead screw driver and gently scrap it off to clean the metal. What i found makes it very easy to install the springs is take a 13mm 3/8 shallow socket, put the 13mm end over the end of the coil and insert the spring thru the end that your ratchet goes on. Push down and youll feel it grab onto the terminal. The socket prevents the spring from cocking sideways and assures that you can push it onto the coil far enough. If you dont replace them, make sure all the boots are good, and all the plugs are new as well as running some injector cleaner on your next fill up, and clean the maf sensor. Also make sure ur air filter is clean. If you do that your mileage should increase signifigantly.

Hope this helps,

Andy

 

[Adieu]

NEVER wash a Triton V8... liquids under the hood can kill both coils and injectors easily on Ford 8 cylinders

and be reaaaaally watchful for coolant leaks or spills (that stuff refuses to evaporate)

 

[nerdwrench87]

plugs were all good. after checking mileage out of a few tanks, I'm now getting 18.5MPG. I DEFINITELY cannot complain about that. Did the GOTTS mod and cleaned the MAF. Still need to clean the IAC, as it sounds like there is a very loud hum at idle that goes away once I give it gas.

I know I need to cut the hoses to flush the heater core, but I am putting that off as long as I can, since its such a PITA.