I have a 1998 Taurus 3.0 duratec V6 24valve. two of the four injectors are
not firing. looking from the front of the engine (passengers side) injectors
1-3 are firing 2-4 are not. there 12VDC at all with key on engine off. the
car runs with a miss. This problem suddenly occured with no known causes...
no wet driving, wrecks or repair work. a scan shows that it is missing on
two cylinders and that the coil pack is likely. but this was switched with
no cure.
My question is.
1. is the a truly sequential system or does it fire two injectors at a
time... 1-3, 2-4?.
2. are there any causes outside of the computer that will cause this?.bad
connector, broken wire...etc.
Thanks in advance for any input/ suggestions.

id check injector with ohms meter,compare the two not fireing to the
ones fireing . i think about 11 ohms is normal. if an injector has
shorted out ,the drivers in the computer can be damaged . i put a noid
light on injector lead to see if its pulsing or not , that would
indicate if computer drivers are still sending. lucas

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Well..... you have a V6.... right way, we know you have 6 fuel injectors
rather than 4.... More importantly, we have to discover how you know that
your concern is with two injectors "not firing". I imagine you unplugged
them? All that is going to indicate is if those cylinders are contributing
or not....

Without having the time to look at the manual, most of these SEFI systems
will resort to "bank firing" at various times - this is dictated by
operating strategy programmed into the PCM.

On testing injector resistance/continuity.... By all means, check it... but
it isn't the last word on whether an injector is flowing or not.
Additionally, the chances that two injectors would be affected at the same
time should ring some bells....

Getting back to the 1-3 and 2-4 concept.... Since this is a V6 with a "waste
spark" ignition system, cylinder numbering becomes of paramount importance.
Cyliunders 1 through 3 are at the rear side of the motor (against the
firewall) and are numbered from right to left (passengers side to drivers
side - to try and keep confusion to a minimum, the sides of the car are
ALWAYS considered as if we are sitting in the drivers seat.... ALWAYS.... NO
EXCEPTIONS... and it doesn't matter what way anything is pointing). In this
manner, we can decide if any two cylinders would be running mates and this
might direct our thoughts to an ignition concern rather than an
injector/fuel concern.... And let's not forget about testing compression.

DTCs.... trouble codes.... these can help immensely.... Do you have a P030?
.... this would be a misfire detection code.... This is known as a "symptom
code" since many things can cause a misfire... Other DTCs can indicate
electrical malfunctions and might be considered "causal" codes... learning
the distinction is invaluable.

My best suggestion... study the system a little.... gain a better
understanding of it.... ask questions before assuming things....


"shylow101" <123@anytown.net> wrote in message
news:48dba5ac$0$5503$bbae4d71@news.suddenlink.net. ..
>I have a 1998 Taurus 3.0 duratec V6 24valve. two of the four injectors are
>not firing. looking from the front of the engine (passengers side)
>injectors 1-3 are firing 2-4 are not. there 12VDC at all with key on engine
>off. the car runs with a miss. This problem suddenly occured with no known
>causes... no wet driving, wrecks or repair work. a scan shows that it is
>missing on two cylinders and that the coil pack is likely. but this was
>switched with no cure.
> My question is.
> 1. is the a truly sequential system or does it fire two injectors at a
> time... 1-3, 2-4?.
> 2. are there any causes outside of the computer that will cause this?.bad
> connector, broken wire...etc.
> Thanks in advance for any input/ suggestions.

On Thu, 25 Sep 2008 09:52:08 -0500, "shylow101" <123@anytown.net>
wrote:

>I have a 1998 Taurus 3.0 duratec V6 24valve.injectors
>1-3 are firing 2-4 are not.
> My question is.
>1. is the a truly sequential system or does it fire two injectors at a
>time... 1-3, 2-4?.
>2. are there any causes outside of the computer that will cause this?.bad
>connector, broken wire...etc.
>Thanks in advance for any input/ suggestions.

According to the factory data (via alldata) for my 99 duratec...each
coil fires 2 cylinders on every stroke (waste spark system). cylinders
1/5 3/4 2/6 are paired.

FI is true sequential, every other stroke.

before spending any money on parts, consider getting an alldata
subscription and running thru the diagnostic routines. It's saved me
loads of $$ and time over the years.

www.alldatadiy.com

--Don



Don Byrer KJ5KB
Power & Glider Pilot Guy
kj5kb-at-hotmail.com

"I have slipped the surly bonds of earth; now if I can just land without bending the gear..."
"Watch out for those doves...<smack-smack-smack-smack...>"