engine problem 4.9L
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engine problem 4.9L
I have a 90 F250 with a 4.9 six, the problem that Iam having is that when it is cold it runs ok, but when it warms up it runs like crap. it wont run right till around 2200 rpm. On occaission it will lean pop. I have ran the codes and it comes up with a 41 code, and says that it is lean thru out the operating range. The spark plugs look fine except for a hot spot on side which left me thinking that it was an intake vaccum leak. What i found was no leak at all. My guess is that it may be the egr system acting up, possable the egr diverter valve sending all the air and gasses into the engine at all times insted of the exhaust and engine. I would like any help with this problem. I have changed the o2, egr, the sensor at the bottom of the distribter, new plugs, wires cap and rotor.
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
engine problem 4.9L
To check the EGR, start the truck and let it idle while you either a) hook direct engine vacuum to its port to open it, b) apply vacuum to its port with an external source, or c) push the valve open by sticking something thru the openings on the diaphragm housing. In any case, the engine should sputter badly & die when the valve opens. If it keeps running basically the same, then either the valve was already open, or its passages are blocked.
You should check the vacuum to get an idea of what's up.
You should check the vacuum to get an idea of what's up.
New User
Joined: Feb 2003
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engine problem 4.9L
I have what sounds like a similiar problem on my 87' f-150 ..
My posting is in the 'INLINE 6' Motor section tiltled:
CARDIAC ARREST!!!
I'm still working on resolving my problem but have made
some progress ...
This past weekend I installed a 'RESTRICTOR PLATE' on the
EGR valve ... which basically cuts it off but still allows the
computer to think it's doing it's thing ....
It was no big deal ... got some high temp gasket material
and a piece of 'flashing' ... traced the EGR valve connection
and made '2' gaskets and a plate ..... and slapped em' in
there ....
Also bumped my timing up a bit to a strong 11+ and it
seems to have made a difference although I'm not totally
convinced that my problem is resolved ....
There were some other things suggested as well ... so check
out the 'INLINE 6' forum for yourself!!
doc brown
My posting is in the 'INLINE 6' Motor section tiltled:
CARDIAC ARREST!!!
I'm still working on resolving my problem but have made
some progress ...
This past weekend I installed a 'RESTRICTOR PLATE' on the
EGR valve ... which basically cuts it off but still allows the
computer to think it's doing it's thing ....
It was no big deal ... got some high temp gasket material
and a piece of 'flashing' ... traced the EGR valve connection
and made '2' gaskets and a plate ..... and slapped em' in
there ....
Also bumped my timing up a bit to a strong 11+ and it
seems to have made a difference although I'm not totally
convinced that my problem is resolved ....
There were some other things suggested as well ... so check
out the 'INLINE 6' forum for yourself!!
doc brown
New User
Joined: Mar 2003
Posts: 2
Likes: 0
engine problem 4.9L
Im having the same problem with my 1988 ford 4.9l you can pull the #5 spark plug wire off and no change in engine.Ive changed plugs, wires,distr,and rotor button.This started all of a sudden cant understand it one mac. wants around 700.00 just to start saids valve stuck or broke is there anything i can try first.And i know nothing about fuel injected engines i can fix,work on old trucks,cars but these news ones everything under the hood has a warning lable on it.
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
engine problem 4.9L
drag
Ford's EFI system is much easier to work on than any carb because it's fairly intuitive and will tell you what's wrong.
Obviously, your #5 cyl isn't firing even when the spark plug IS hooked up, so you only have to find which of the basic components of combustion are missing: air (#5 intake valve & piston), gasoline (#5 fuel injector), compression (#5 piston, rings, cylinder, & valves), or spark (PIP, dist. cap, #5 plug wire, #5 plug). Use a screw-in compression tester, a vacuum gauge, & a digital multimeter to check. Swap the plug & wire with another cylinder to test them. Use the inside back cover of the Haynes manual to ID the problem with that plug.
Ford's EFI system is much easier to work on than any carb because it's fairly intuitive and will tell you what's wrong.
Obviously, your #5 cyl isn't firing even when the spark plug IS hooked up, so you only have to find which of the basic components of combustion are missing: air (#5 intake valve & piston), gasoline (#5 fuel injector), compression (#5 piston, rings, cylinder, & valves), or spark (PIP, dist. cap, #5 plug wire, #5 plug). Use a screw-in compression tester, a vacuum gauge, & a digital multimeter to check. Swap the plug & wire with another cylinder to test them. Use the inside back cover of the Haynes manual to ID the problem with that plug.
New User
Joined: Mar 2003
Posts: 2
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engine problem 4.9L
ive changed spark plugs and wires ive switched plugs and still nothing i had a friend look at it today at he said it didnt sound like a valve.I have compression on piston but i have had no luck finding a compression gauge??any in put would be greatly helpfull.i think im going to try to fix it my self my friend saids theres nothing to it ..
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
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New User
Joined: Jul 2007
Posts: 2
Likes: 0
I have what sounds like a similiar problem on my 87' f-150 ..
My posting is in the 'INLINE 6' Motor section tiltled:
CARDIAC ARREST!!!
I'm still working on resolving my problem but have made
some progress ...
This past weekend I installed a 'RESTRICTOR PLATE' on the
EGR valve ... which basically cuts it off but still allows the
computer to think it's doing it's thing ....
It was no big deal ... got some high temp gasket material
and a piece of 'flashing' ... traced the EGR valve connection
and made '2' gaskets and a plate ..... and slapped em' in
there ....
Also bumped my timing up a bit to a strong 11+ and it
seems to have made a difference although I'm not totally
convinced that my problem is resolved ....
There were some other things suggested as well ... so check
out the 'INLINE 6' forum for yourself!!
doc brown
My posting is in the 'INLINE 6' Motor section tiltled:
CARDIAC ARREST!!!
I'm still working on resolving my problem but have made
some progress ...
This past weekend I installed a 'RESTRICTOR PLATE' on the
EGR valve ... which basically cuts it off but still allows the
computer to think it's doing it's thing ....
It was no big deal ... got some high temp gasket material
and a piece of 'flashing' ... traced the EGR valve connection
and made '2' gaskets and a plate ..... and slapped em' in
there ....
Also bumped my timing up a bit to a strong 11+ and it
seems to have made a difference although I'm not totally
convinced that my problem is resolved ....
There were some other things suggested as well ... so check
out the 'INLINE 6' forum for yourself!!
doc brown
Did you found the problem finally ?
Mine do the same thing as your.
When he's cold run perfect.
When he's hot run crap. looks like it's missing 1 cylinder ?
Than'ks
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