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4 and 6 Cylinder misfire I checked fuel pressure (OK)

Tiny
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  • MEMBER
  • 2002 FORD ESCAPE
  • 190,000 MILES
2002 Ford Escape V6 3L - 4&6Cyl misfire. I check : fuel pressure (OK), compression (OK), coils (OK), spark plugs (new), injectors(OK) but I don't now if is signal from computer. Catalytic converter on this side is melted inside. Only 304 & 306 codes in memory.

2 years ago same side cylinder. Misfire and cat was melted. I put new cat and new coils / plugs.

Pleas help me, great site for me :-)
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Monday, February 6th, 2012 AT 12:31 AM

32 Replies

Tiny
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  • 6,110 POSTS
Are the plugs getting spark?
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Monday, February 6th, 2012 AT 12:50 AM
Tiny
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Yes I have sparks.
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Monday, February 6th, 2012 AT 1:36 AM
Tiny
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How did you check fuel pressure and the injectors?
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Monday, February 6th, 2012 AT 1:50 AM
Tiny
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I rent fuel pressure test kit - with engine off and running was 65psi. I don't now if fuel pressure regulator is good - no change when I disconnect vacuume hose. When pressure was on I check each injector for (spray) by two wires + & -. They was working (no leaking).
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Monday, February 6th, 2012 AT 3:18 AM
Tiny
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Are the injectors being pulsed when you try and start the engine? Will it start if yo spray carb cleaner in the intake?
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Monday, February 6th, 2012 AT 3:53 AM
Tiny
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I have no problem to start engine but is not working on 4 & 6 cyl. - Is shaking.
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Monday, February 6th, 2012 AT 11:06 PM
Tiny
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Disconnect the fuel injector harness and measure the resistance of #s 4 and 6. See attached for specification.
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Monday, February 6th, 2012 AT 11:45 PM
Tiny
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I would also check compression and make sure the injectors are being pulsed.
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Monday, February 6th, 2012 AT 11:52 PM
Tiny
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Resistance is OK, I check all 6. Compression is 195-205 at all 6 cyl.
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Tuesday, February 7th, 2012 AT 1:46 AM
Tiny
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Can you move the individual injectors around? Like put #3 into #4, and #5 into #6, and vice versa. See if the problem follows the injectors. What about plug wire impedance?

If I recall this has a distributor. What does it look like? What about the cap?
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Tuesday, February 7th, 2012 AT 3:48 AM
Tiny
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There is no plug wire, distributor or cap. This is coil on plug system.
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Tuesday, February 7th, 2012 AT 11:35 PM
Tiny
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Can you move the COP assemblies around then? To see if maybe they or their wiring is the issue.
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Tuesday, February 7th, 2012 AT 11:46 PM
Tiny
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That was first think I did - always 4 & 6 misfire.
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Wednesday, February 8th, 2012 AT 12:42 AM
Tiny
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Ok. That means it's either the plugs, the connector for the COP assembly, or bad compression in those 2 cylinders.
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Wednesday, February 8th, 2012 AT 1:07 AM
Tiny
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Were you able to swap injectors around?
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Wednesday, February 8th, 2012 AT 1:10 AM
Tiny
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All injectors works same, compression is same on each cylinder, plugs are new, connectors OK.
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Wednesday, February 8th, 2012 AT 1:42 AM
Tiny
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Measure voltage at each COP assembly with the engine running. I have attached the pertinent schematic. Make sure #4&6 are being triggered properly and powered.
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Wednesday, February 8th, 2012 AT 3:33 AM
Tiny
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I can't read - letters to small.
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Thursday, February 9th, 2012 AT 1:46 AM
Tiny
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Download it. I expanded it to over 14 inches wide in actual size.
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Thursday, February 9th, 2012 AT 4:12 AM
Tiny
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How to download this?
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Friday, February 10th, 2012 AT 2:54 AM

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