blinking check engine lamp

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Frosty - 29 Dec 2006 04:02 GMT

Hi All,

I have a 2003 Aviator with a 4.6L. The Check Engine light came on with
codes 0302 and 0308 (misfires). The dealer changed the plugs and
cleared the codes. One week later the engine has no power under load
and the check engine light is blinking and turns off... a total of 9
times now. I know that one reason for a blinking lamp is that misfires
are so severe that raw fuel is being dumped out the exhaust and can
cause severe damage. Oddly, there are no OBD codes stored when the
check engine light blinks so the dealer told me there was nothing they
could do. Does anyone know why the check engine lamp blinks without
storing codes? The dealer apparently will not troubleshoot misfires
without codes. There must be a reason for the light to blink and not
store codes.

Thanks for your assistance,
Jim

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NeedForSpeed3685 - 30 Dec 2006 16:15 GMT

I'm no expert, but I know my Fords and I've owned nothing but...

The Check Engine light is flashing because a major misfire has occured,
badly enough to risk damage to the catalytic converter. Misfiring
problems are most commonly caused by such things as a bad spark plug,
bad spark plug wire, or ignition coil/module problems. Since you've
had the plugs changed, re-check the dealership's work.

I've seen tooo many cases where someone has a major misfire occuring
from a disconnected vacuum line or re-arranged spark order (wrong
ignition wire on a cylinder).

Your ignition system should have markings to indicate the "cylinder
number" on top of the distribution coil packs. Follow each wire to
it's respective cylinder and make sure none are crossed. If the
computer thought it was firing a different cylinder than it actually
is, obviously the spark/fuel/compression cycle will be off and fuel
won't burn properly, or at all.

Next items to check would be the intake and exhaust systems. Check for
loose connectors and vacuum hoses. Make sure the intake tubing is
securely attached and no leaks occur.

Underneath, check both exhaust Oxygen sensors.

More than likely, you will find something wrong with one of these many
systems. If not, you may want to consider replacing the ignition
wires. These run anywhere from $30-$90, depending on your engine, so I
would wait to rule out other problems before replacing these.

Good luck! Has there been any significant work performed on the engine
other than the spark plug change recently?

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Ford Tech - 07 Jan 2007 11:22 GMT

> Hi All,
>
[quoted text clipped - 13 lines]
> Thanks for your assistance,
> Jim

Ya know there is actually a TSB out for this concern, and it states in
the TSB that the condition generally occurs on the left bank only. are you
sure he only replaced spark plugs? This TSB has them checking compression
and cylinder leakage, and all kinds of things. It also has them installing
new heads if a valve train problem is found... It even has head part numbers
listed right on the tsb.. I would say you could have a very serious
compression problem with your car. BUT, the tech cleared those codes and now
they have to reset in order to do any more work.
One more thing. Have they tried to see if there are any codes stored in
memory since the repair? The CEL can go off, but codes can be stored. I
would have them check for stored codes..

Ford Tech

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