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04 Monterey misfire

Tiny
J.STIEG
  • MEMBER
  • 2004 MERCURY MONTEREY
  • 190,000 MILES
Having misfire problems with 3rd cylinder, I got code p0303 and another code that said problem before 1st 1000 revs.
Friday, June 24th, 2011 AT 5:44 PM

25 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
P0303: Check the no.3 cylinder's -sparkplug, compression and injector-let me know
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Friday, June 24th, 2011 AT 7:31 PM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
I swapped spark plug and wire from cylinder 2 and put them on 3 and problem still came back to cylinder 3. I checked compression on cylinder 3 and it was over 100psi in first stroke and 150 in next and so on up to 200psi with engine off and just cranking with throttle open.
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Friday, June 24th, 2011 AT 9:45 PM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,005 POSTS
Coil packs on all plugs?

Swap it to another, see if misfire changes cylinders.

Recently had same similar issue with Wifey's '03 Escape---I do not know your rig, but I hope you do not have to disassemble the engine, as I did, just to get to the back 3 plugs!

This has been a commercial break, from CJ MEDEVAC

Continue to follow RAZ'S instructions. These new things kill me!

The Medic
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Saturday, June 25th, 2011 AT 12:02 AM
Tiny
RASMATAZ
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Medic, if its COP it doesn't have S/P wire -DIS or TFI Ignition system? You got a lot of car problems hang in there -I'm also responding to your New Yorker

200 psi-lil too muchy-could be a carboned-up cylindercausing it to raise. Have you check the injector-try checking its solenoid resistances and spray pattern/PWM
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Saturday, June 25th, 2011 AT 1:10 AM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
Ok, I will check "injector coil" resistance and compare with other injector,

do you think the misfire on cly3 is spark or fuel injector related?
Note: problem seems to be more repetitive and less intermittent now than a few weeks ago.
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Saturday, June 25th, 2011 AT 1:49 AM
Tiny
RASMATAZ
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Dunno yet-till you check it
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Saturday, June 25th, 2011 AT 2:33 AM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
I checked injector resistance and they all seemed to be around 12.4 Ohms including #3.
I also checked injector spray on #3 and it came out as an even cone pattern. I tested injector spray by supplying voltage to the injector. Where do I go from here?
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Monday, June 27th, 2011 AT 1:36 PM
Tiny
RASMATAZ
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Inspect and test the camshaft and crankshaft position sensor
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Monday, June 27th, 2011 AT 11:19 PM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
I am ready to do that, I'v tested sensors like that before. I think They all have three wires. Can you give diagram, and while I rotate engine what wires should I be checking for.

Question: will a bad crank sensor repeatedly trigger the #3 cylinder misfire? I reset dtc's three times back to back before working on engine.
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Monday, June 27th, 2011 AT 11:34 PM
Tiny
RASMATAZ
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See below
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Tuesday, June 28th, 2011 AT 12:02 AM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
Each of the sensors have two wires. I checked the resistance on the crank sensor, and while rotating I got ohms from 1250 ohms to 130 ohms. At all positions not moving I got 642 ohms.

For cam sensor it was at 591ohms not moving, and 830ohms high side and 450ohms on low side
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Tuesday, June 28th, 2011 AT 1:59 AM
Tiny
RASMATAZ
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Not too sure -I don't have the specs for it-Have you check the sparkplug wire resistances on no.3 if not do so-
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Tuesday, June 28th, 2011 AT 2:30 AM
Tiny
J.STIEG
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  • 352 POSTS
When I started diagnosing the problem I swapped the plug and wire from cyl#2 and put on cyl#3, and #3 to #2. Code always came back to cyl#3 repetitive.

Whats causing the cly#3 to set?
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Tuesday, June 28th, 2011 AT 3:16 AM
Tiny
RASMATAZ
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Test the coil resistances primary and secondary windings for no.3
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Tuesday, June 28th, 2011 AT 6:48 AM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
I think it could be the waste system. Do you have diagram? Thanks
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Tuesday, June 28th, 2011 AT 11:34 AM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
I checked the three places for primary resistance all being consistant at 1 ohm. Secondary seemed infinite on all. I look closely at #3 coil tower for cracks, din't see any.
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Tuesday, June 28th, 2011 AT 12:50 PM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
Here are some readings I got from plug wires in ohms.

Cylinder# 1 2 3 4 5 6
plug wire length inches 22 14 14 40 38 42
resistance in ohms 7.1k 4.5k 4.2k 11.7k 11.8k 13.5k
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Tuesday, June 28th, 2011 AT 5:43 PM
Tiny
RASMATAZ
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Try swapping injector for no.3 and see if I moves-
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Tuesday, June 28th, 2011 AT 5:53 PM
Tiny
J.STIEG
  • MEMBER
  • 352 POSTS
Yes I swapped it around. Have not tried it yet because upper manifold is so hard to remove just tring to get every thing done before it goes back on.
I also checked wires pcm to injectors and pcm to ign coil. All wires are fine with no opens and ohms at.5, I will see how injector swap goes and post results.
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Tuesday, June 28th, 2011 AT 6:29 PM
Tiny
J.STIEG
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Put it all back together and It still says misfire on cylinder #3
Do you know if a bad crank sensor would set off a code for just cyl #3?
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Tuesday, June 28th, 2011 AT 9:30 PM

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