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Frustrated
Dodge Dakota
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7/26/2011
08:39:09
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 Subject: Misfire, cylinder 4 plug soaked in oil?
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Message:
I'm looking for some reassurance. I'm in the process of
replacing my plenum gasket because the intake had a good
puddle of oil inside. The pcv line seemed fairly dry(not wet
enough to to form a puddle). My problem is this engine was
just rebuilt 25,000 miles ago so how is the plenum gasket
already bad? I know the magnum engines are notorious for
this. My main concern is my truck sounds like it's running on
4 or 5 cylinders. There's a complete loss of power so I
checked compression and have 175-180 in all cylinders. I
also checked for spark and every cylinder seems fine there.
Fuel pressure is 45 psi.
In the past I had issues getting
it started maybe 4-5 times with the rebuilt engine. I'd let it sit
for a day and it would run and start fine after. That had me
thinking I might have a bad cam sensor? That still doesn't
explain the puddle of oil at the bottom of the intake though.
Right now I'm in the process of changing the plenum gasket
with the Hughes kit so I'll post any progress if it's better.
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daddio
Dodge Dakota
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7/26/2011
11:03:19
|  RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
What year is your truck?
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Frustrated
Dodge Dakota
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7/26/2011
13:44:22
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
99
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daddio
Dodge Dakota
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7/26/2011
16:32:09
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
Let us know what you find after changing the plenum gasket. That #4 plug, the electrode was soaked with oil?
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Frustrated
Dodge Dakota
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7/27/2011
07:17:00
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
Yea the whole plug was black and shiny. The injector had
signs of oil on it too. I bought new injectors so it's not
injectors either
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daddio
Dodge Dakota
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7/27/2011
08:08:15
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
How did the compression test look on this cylinder? Could be a broken oil control ring or a bad valve stem seal. Was there a warranty on the rebuild?
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Curly
Dodge Dakota
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7/27/2011
14:57:40
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
If that cylinder is getting oil into then
compression reading has to be lower then other
cylinders. Did you have throttle wide open when you
did the compression test?
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Frustrated
Dodge Dakota
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7/28/2011
07:21:19
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
I was afraid of the same thing but the compression read 175
which was just about on with the other cylinders which read
somewhere between 175-180. I ran the compression test
without the throttle body on and the plugs out. I was
wondering if that would change the results of the test?
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Curly
Dodge Dakota
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7/28/2011
09:49:36
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
It was a good test then, Only other thing it could
be in a valve seal. with only one seal failing then
it wasn't done right. If you can find the tools and
have the know how you can change it right on the
engine without pulling the head off.
|
Frustrated
Dodge Dakota
JOIN HERE
8/14/2011
20:12:31
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
Alright so I finally finished the plenum gasket,
yea I know it took awhile, I just haven't been in
the mood to work on the truck. Needless to say it
still runs poorly so I'm assuming its a bad valve
seal? I know a bit about engines but lack
information on valve seals, why would this
necessarily cause misfiring? Even after cleaning
off the spark plug it misfires so it cant be the
fouling of the plug that's causing the misfire. I
was almost certain that it was either poor spark,
no fuel, low compression in cylinder four, or a
vacuum leak but I can't seem to find the cause.
Like I mentioned before the compression test
showed 175-180 in all cylinders. Would a leak down
test help?
|
Frustrated
Dodge Dakota
JOIN HERE
8/24/2011
18:21:25
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
Ok, so I just did a leak down test and i tried
cylinder four first, it showed roughly just under
45% leakage which is close to the ok range but it
fell into moderate. I tried cylinder one just for
comparison purposes which showed about 35%.
Regardless of the difference in % I was getting
noise from the oil dipstick and oil cap from both
tests in cylinder 4 and 1, nothing from the
overflow bottle, intake, or exhaust.
Also I tried hooking up a timing light to cylinder
four and noticed that the light wasn't flashing
consistently like all the other
cylinders(sometimes id get a second or two with
now spark) which is leaving me to think that the
spark is off in cylinder four causing it to
misfire. Only question is why is one cylinder
doing this compared to all the others? I think the
crank sensor and cam sensor only control injector
pulse? Either way i already replaced the rotor and
cap so its definitely not that. Any help would be
appreciated
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daddio
Dodge Dakota
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8/25/2011
12:57:43
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
This is a 3.9 V6 right? If it is and your timing light acted up on cylinder #4, try changing that plug wire.
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Frustrated
Dodge Dakota
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8/26/2011
17:10:43
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
Yes this is a 3.9
I checked for spark at the cap and its almost
nonexistent you can see a few small jumps to the
screw driver but its very weak. I have no clue what
would cause spark failure in one cylinder?!
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daddio
Dodge Dakota
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8/26/2011
17:50:42
| RE: Misfire, cylinder 4 plug soaked in oil?
IP: Logged
Message:
Have you done a complete tune up on this truck lately? Also, are you running an aftermarket coil?
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Frustrated
Dodge Dakota
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8/29/2011
09:49:47
| RE: Misfire, cylinder 4 plug soaked in oil?
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Message:
Yea I just recently put new plugs, wires, cap and rotor.
Maybe 15,000 mi ago. I also have an accel coil on it. I've
been trying to find my old coil to swap in to see if it'll fix but as
of now the thing seems to be lost.
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daddio
Dodge Dakota
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8/29/2011
13:18:06
| RE: Misfire, cylinder 4 plug soaked in oil?
IP: Logged
Message:
Check your cap and rotor. With a higher than stock voltage coil, you will go through caps and rotors quicker than with the stock. you may also want to try replaceing that #4 wire.
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Frustrated
Dodge Dakota
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8/29/2011
15:53:53
| RE: Misfire, cylinder 4 plug soaked in oil?
IP: Logged
Message:
I just replaced the cap and rotor I thought the same thing too
it didn't fix it. What I'm confused about is the check engine
light hasn't come on with such an obvious misfire
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