My F150 is my once a month vehicle, and the other day when I tried to
start it, it turned over about 3/4 then stopped cold, like something
was blocking something. any advise what it could be? my friends and I
say that it is either something wedged in the starter area or possibly
a stuck vavle wedged against a piston. snows pretty deep and I'd
prefer to work on it when warm, so I don't have any rush to find out.
Pull the plugs an turn it over to find the one full of fuel
or water and hope you did'nt bend a rod or crack a piston
when it locked. This can on rare occasions be caused by a
stuck valve but, I don't recall that being an interference
engine offhand. It will be best to turn it by handwith the
plugs already out . Fuel means a leaky injector - water is
usually a head gasket. Water in the oil is also a bad sign.
You might have a 'compression lock' or a 'water lock' on the rotating
mechanism of the pistons and crank shaft.
Crack a block and get water to seep into the piston, it fills the top as
the values are closed on the compression stroke ... and the engine
stops, sometimes it will even whine a bit before it stops ...
as you would whine as well if someone was kicking you in the ass to turn
over and you couldn't.
Soooooo ... pull the truck into your gargage, thaw it out, pull the
spark plugs, and see if you can crank it by hand in a backwards
direction and then in a forwards direction until it stops again or not.
If it stops with the spark plugs pulled .. then a mechanical function is
broken, a piece of metal is in there hindering the rotation the engine
pistons and crank.
If it all moves, then put it together with the plugs back in, check for
spark, add engine start to the fuel system, and give it a crank.
Not work again, then check for the compression, vapor, water lock stuff
again. It is likely to be made known to you what it is at this time if
you have not figured it out when you take it and thaw it out.
hope that helps ...
On Mon, 08 Feb 2010 19:43:38 -0800, "Alan B. Mac Farlane"
He should not turn these engines backwards with the
hydraulically tensioned timing chains. If the plugs are
out, he should be able to turn it in it's normal rotation.
It should also be turned at least 2 complete revolutions to
make sure all cylinders have been fully cycled. He should
see the suspect cylinder (not always) when the plugs are
pulled. If there is a lot of fluid in a cylinder that is
just beginning the compression stroke, it may lock before
any liquid is pushed up to the plug. That is the reason for
hand rotation in it's normal direction.
ya lugnut .. this is sooo easy to Dx once the plugs are pulled.
he will see what the problem is real quick ...
if he has any eye for reading plugs.
This has been going down for some time and a hard freeze is what pulled
it over just like taking a borderline battery down.
IMO and all that rot.
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