Missing 5.4
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Elder User
Joined: Apr 2004
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From: New Roads, La
Missing 5.4
Hey, I have a '00 f250 w/ the 5.4 lately it started 2 miss. i was told that it was a coil or COP. The mechanic said his machine wouldnt work unless the service light was on. i was wondering how i could tell for myself witch one isnt working so i dont have to pay $70x8 to get them all replaced. Or if i cant just figure out witch one is missing then how to make the check engine light come on. Any help is appretiated Garrett Couch
Cargo Master
Joined: May 2001
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obdII may or may not flag it. I have seen them missing badly and never turn on a cel. Or log a pending. I have an OBDII scanner set up on my laptop and it sometimes will show one pending some times it doesn't. I had them flag cylinder misfire and never feel it miss and I have had them with a dead miss I mean a spark plug wire the was totally open and not fllag anything. just unhook the power wire to each coil and see if the engine acts differently. Wihen you find the missing cyl nothing will change then go from there a new plug/coil/injector.
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Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
The Ford scan tool doesn't need a CEL to detect a misfire. It watches all PCM functions in real time. An occasional miss will not always throw a code. It could be something else causing the miss IE; bad injector, TPS, ETC.
How many miles are on it and has it ever had plugs put in it?
How many miles are on it and has it ever had plugs put in it?
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From: New Roads, La
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From: APACHE JCT ARIZONA
From My Knowledge It Is 90% Of The Time The #4 Coil That Builds Up Leaking Antifreeze On The Top Of The Coil. It Leaks From The Hose That Runs Above The Cop. #4 Is Located On The Passenger Side, It Is The Coil Closest To The Firewall.
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Joined: Dec 2004
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I have the same problem, a misfire. I checked each coil as the Haynes manual said. "0.55 ohms Primary resistance (the 2 input pins at the top) and 5,500 ohms secondary resistance (input pin to spark plug out put)". Every one checked good. Some one suggested an infared thermometer on the exhaust manifold. It was also suggested to use a stethoscope on each fuel injector??
Junior User
Joined: Jun 2004
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Checking coils with a couple volts provided by an ohm meter won't necessarily tell you much about how well a coil does with 40,000 volts applied.
Even though no trouble code has been set, even cheap code readers will at least provide you with Pending Codes; and an inexpensive scanner will provide detailed info. Although no code was set, this is a small sampling of the kind of info my EZ-Scan 6000 provided in response to a weak #5 COP:
Pending: DTC P0300 random/multiple cylinder misfire detected
$53 $04 Pass
Pass High 0000 <= FD00
Cyliner #4 Misfire Rate Exceeding 200 Rev Type A Threshold
$53 $05 Pass
Pass High 12B6 <= FD00
Cyliner #5 Misfire Rate Exceeding 200 Rev Type A Threshold
$53 $06 Pass
Pass High 00D1 <= FD00
Cyliner #6 Misfire Rate Exceeding 200 Rev Type A Threshold
$53 $07 Pass
Pass High 0000 <= FD00
Cyliner #7 Misfire Rate Exceeding 200 Rev Type A Threshold
$54 $00 Pass
Pass High 1763 <= FD00
Highest Type A Misfire Rate Exceeding 200 Rev Type a Threshold
$55 $00 Fail
Fail High 13AF not <= 0A3D
Highest Type B Misfire Rate exceeding 1000 rev Type B threshold
Even though no trouble code has been set, even cheap code readers will at least provide you with Pending Codes; and an inexpensive scanner will provide detailed info. Although no code was set, this is a small sampling of the kind of info my EZ-Scan 6000 provided in response to a weak #5 COP:
Pending: DTC P0300 random/multiple cylinder misfire detected
$53 $04 Pass
Pass High 0000 <= FD00
Cyliner #4 Misfire Rate Exceeding 200 Rev Type A Threshold
$53 $05 Pass
Pass High 12B6 <= FD00
Cyliner #5 Misfire Rate Exceeding 200 Rev Type A Threshold
$53 $06 Pass
Pass High 00D1 <= FD00
Cyliner #6 Misfire Rate Exceeding 200 Rev Type A Threshold
$53 $07 Pass
Pass High 0000 <= FD00
Cyliner #7 Misfire Rate Exceeding 200 Rev Type A Threshold
$54 $00 Pass
Pass High 1763 <= FD00
Highest Type A Misfire Rate Exceeding 200 Rev Type a Threshold
$55 $00 Fail
Fail High 13AF not <= 0A3D
Highest Type B Misfire Rate exceeding 1000 rev Type B threshold
Postmaster
Joined: Apr 2003
Posts: 2,703
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From: Harrisburg, NE
does each cop have its own number? as in will a #3 cop on #8 still read as a #3?
and could a torn boot possibly cause a misfire?
sorry about the highjack
we got a 100 code reader from wally world thats has worked well so far. i just wish that it was able to do a power balance test (same thing as unplugging a cop) like the cheapie actron that i have for my ranger
and could a torn boot possibly cause a misfire?
sorry about the highjack
we got a 100 code reader from wally world thats has worked well so far. i just wish that it was able to do a power balance test (same thing as unplugging a cop) like the cheapie actron that i have for my ranger
Senior User
Joined: Oct 2004
Posts: 422
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From: N. Carolina
The COP's are interchangeable ... they are not "assigned" a cylinder number. You can put any one in any cylinder.
For instance (and my recommendation), when my 5.4L was reading 3 bad COP's, I replaced 'um .... but I put the new one's in the back where it's hard to get to and moved the older one's to the front where it's easy to get to. That way if the older one's ever go bad it would be a big thing to change 'um out!
A torn boot could possibly cause a mis-fire, as most likely if the boot was torn then it may be damaged else where. But rather than just replacing the boot, you would be better of in the long run with replacing the entire COP ... IMO.
For instance (and my recommendation), when my 5.4L was reading 3 bad COP's, I replaced 'um .... but I put the new one's in the back where it's hard to get to and moved the older one's to the front where it's easy to get to. That way if the older one's ever go bad it would be a big thing to change 'um out!
A torn boot could possibly cause a mis-fire, as most likely if the boot was torn then it may be damaged else where. But rather than just replacing the boot, you would be better of in the long run with replacing the entire COP ... IMO.
Last edited by 98SurplusExpy; Dec 7, 2004 at 11:03 AM.
