Before performing ANY diagnostic procedures on your engine...


AllanD

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I see this time and time again "my engine does this and that!"

And there's usually a raft full of followup questions people ask
trying to work the problem....

In my considered opinion the FIRST intelligent question is the one where someone
asks "Have you changed the fuel filter"

All OTHER questions are jumping ahead in the logical thought process

It's like someone saying "I saw a dead animal alongside the road!" and
all the immediate follow-up questions are describing the different known
species of unicorn....

If you suspect that one of your legs is suddenly shorter than the other
you think ya'll might look to see if you are wearing shoes that match
rather than a wrestling flat on one foot and a cowboy boot on the
other before you rush off to see an orthopedic surgeon to shorten the long leg?

Lack of power on a 4.0 is more often not a fuel issue, because the ignition
generally works... or it doesn't.

there is no question of the ignition of the engine runns at all because the
two common modes are workign perfectly or not at all anything else would
be very odd... one in 10,000.

And if the fuel filter doesn't work pull the lid off the airbox and check for
leaves mouse nests and dead chipmunks (the crap collects UNDER the filter)

Last fall I had a problem, a noticeable "lack of power", I replaced the fuel filter
and it didn't go away... next on my thoughts was the airbox...

what did I find? it was packed full of that silky crap that the rag weed and milk
weed plants use to distribute their seeds on the wind....

Yup my airbox had collected about a pound of the stuff and it was
obstructing airflow into the engine... problem solved... never even
thought of reaching for my EEC4 scanner (I have a good one too, not a $20 "beep box")

Next on my list would have been pulling the spark wirees out of the coil packs
one by one and looking inside, if you see anything other than shiny aluminum
(or brass on an aftermarket "performance coil pack) you've probably found
your problem, but ignition doesn't cause a general lack of power it cause
uneven idle or an outright "miss" ranging from a "soft miss" that you only notice
under specific circumstances to a "hard miss" which is constant under ALL circumstances.

spark plugs can cause some weirdness, generally worn plugs will idle great,
but will only misbehave at high rpm or under heavy load that's because the
bigger the gap or the higher the load even the harder it is to fire the mixture


I might have reached for my code scanner if I had needed to but...


please check the "Stupid stuff" before posting....

AD
 
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Big Jim M

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Persorming???

Persorming??

I see this time and time again "my engine does this and that!"

And there's usually a raft full of followup questions people ask
trying to work the problem....

In my considered opinion the FIRST intelligent question is the one where someone asks "Have you changed the fuel filter"

All OTHER questions are jumping ahead in the logical thought process

It's like someone saying "I saw a dead animal alongside the roadl" and all the immediate follow-up questions are describing the different known species
of unicorn....

If you suspect that one of your legs is suddenly shorter than the other
you think ya'll might look to see if you are wearing shoes that match rather than a wrestling flat on one foot and a cowboy boot on the other before you rush off to see an orthopedic surgeon to shorteh the long leg?

Lack of power on a 4.0 is more often not a fuel issue, because the ignition generally works... or it doesn't.

there is no question of the ignition of the engine runns at all because the two common modes are workign perfectly or not at all
anything else would be very odd... one in 10,000.

And if the fuel filter doesn't work pull the lid off the airbox and check for leaves mouse nests and dead chipmunks

Last fall I had a problem, a noticeable "lack of power", I replaced the fuel filter
and it didn't go away... next on my thoughts was the airbox...

what did I find? it was packed full of that silky crap that the rag weed and milk weed plants use to distribute their seeds on the wind....

Yup my airbox had collected about a pounbd of the stuff and it was obstructing airflow into the engine... problem solved... never even thought of reaching for my EEC4 scanner (I have a good one too, not a $20 "beep box")

Next on my list would have been pulling the spark wirees out of the coil packs one by one and looking inside, if you see anything other than shiny aluminum (or brass on an aftermarket "performance coil pack)
you've probably found your problem, but ignition doesn't cause a general lack of power it cause uneven idle or an outright "miss" ranging from a "soft miss"
that you only notice under specific circumstances to a "hard miss" which is constant under ALL circumstances.

spark plugs can cause some weirdness, generally worn plugs will idle great, but will only misbehave at high rpm or under heavy load
that's because the bigger the gap or the higher the load leven
the harder it is to fire the mixture


I might have reached for my code scanner if I had needed to but...


please check the "Stupid stuff" before posting....

AD
 

alwaysFlOoReD

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I agree, my diagnostic procedure sucks. I'm one to jump to conclusions so, is there or could you write a general procedure to follow. [Or maybe I'll buy a repair manual :icon_surprised: Even those don't help me much, I'm to easily distracted- oh, that sure is shiny/cool, wonder if I can make one:icon_confused:]
Or a list of more stupid stuff to check first.

Richard
 

Angie

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Engines work on this concept Gas - Air - Spark ... take away one of those and you have a problem (as Allan said) you can't drive on an empty tank so think in this way:

G. gas
A. air
S. spark
 

Jason

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Wouldn't you check the airbox first? I do agree though.

We used to have those "alternator, starter, battery, fuse" type of techs at work. Boy they made me a ton of cash.
 

modelageek

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I see this time and time again "my engine does this and that!"

And there's usually a raft full of followup questions people ask
trying to work the problem....

In my considered opinion the FIRST intelligent question is the one where someone asks "Have you changed the fuel filter"

All OTHER questions are jumping ahead in the logical thought process

It's like someone saying "I saw a dead animal alongside the roadl" and all the immediate follow-up questions are describing the different known species
of unicorn....

If you suspect that one of your legs is suddenly shorter than the other
you think ya'll might look to see if you are wearing shoes that match rather than a wrestling flat on one foot and a cowboy boot on the other before you rush off to see an orthopedic surgeon to shorteh the long leg?

Lack of power on a 4.0 is more often not a fuel issue, because the ignition generally works... or it doesn't.

there is no question of the ignition of the engine runns at all because the two common modes are workign perfectly or not at all
anything else would be very odd... one in 10,000.

And if the fuel filter doesn't work pull the lid off the airbox and check for leaves mouse nests and dead chipmunks

Last fall I had a problem, a noticeable "lack of power", I replaced the fuel filter
and it didn't go away... next on my thoughts was the airbox...

what did I find? it was packed full of that silky crap that the rag weed and milk weed plants use to distribute their seeds on the wind....

Yup my airbox had collected about a pounbd of the stuff and it was obstructing airflow into the engine... problem solved... never even thought of reaching for my EEC4 scanner (I have a good one too, not a $20 "beep box")

Next on my list would have been pulling the spark wirees out of the coil packs one by one and looking inside, if you see anything other than shiny aluminum (or brass on an aftermarket "performance coil pack)
you've probably found your problem, but ignition doesn't cause a general lack of power it cause uneven idle or an outright "miss" ranging from a "soft miss"
that you only notice under specific circumstances to a "hard miss" which is constant under ALL circumstances.

spark plugs can cause some weirdness, generally worn plugs will idle great, but will only misbehave at high rpm or under heavy load
that's because the bigger the gap or the higher the load leven
the harder it is to fire the mixture


I might have reached for my code scanner if I had needed to but...


please check the "Stupid stuff" before posting....

AD
Great honest post.........I am just becoming reasonably comfortable with my knowledge level and I have started to preach what you said.....the fuel filter does not get changed enough and 90% of all issue would not have happened if people followed the maintenance schedule......
 

scheetz21

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Engines work on this concept Gas - Air - Spark ... take away one of those and you have a problem (as Allan said) you can't drive on an empty tank so think in this way:

G. gas
A. air
S. spark
that is true but wont get any where with out compression...suck, squeeze, bang, blow, but usually if your truck that's stops running one day prob is a "GAS" problem.
 

jimbo59

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following previous advice ! lmao ! i have a 2000 ford ranger 4.0 v6 , automatic 4x4 , 272,000 miles and change.

fuel filter changed , spark plugs changed , air filter changed ( with box cleaned out ) and fuel pressure damper replaced .

problem ! when engine is cold it floods all cyclinders with gas ! thus the engine wont start , once i remove all plugs and clean them and blow off excess gas it will start and run , until later when the engine cools and it starts all over again ! sometimes as long as a week later !

it has been in 2 local shops ! to include the local ford dealership ! and no one knows why its doing this ??????

just short of insurance fraud ? and ideas !!!!!!!!!!!!!
 

spiralthomas

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valvetrain...

chased my 94 4.0 isuue for 1&1/2 years, ignition+fuel+eec all gone over. should have listened to the first guy that said 'burnt valve' - the main issue w/these motors seems to be valvetrain(rockers, lifters, pushrods) which look like other problems, especially to those who don't want to believe their engine needs gutting. check the posts regarding valvetrain issues, also check your intake&exhaust bolt torques before it's too late...
 

coopab

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persorming???

Typos are a PITA

AD
Unless the typo makes the meaning unclear I follow this motto from my tagline file.

"All spelling and grammar errors are intentional. Grammar Nazis' need entertainment"
 


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