coil on plug/wiring problems.. plz help!

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usiskin99

New Member

Aug 29, 2007

26

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Weston, Fl.

Sep 30, 2009

#1

• Sep 30, 2009

• #1

ok, this is what happened (01 gt):
was on m way to work when suddenly lost most of the power, engine started shaking and rough running. made it to work, but worried about it went and got a obd scanner. it threw out 4 codes (p0351, 52, 53, and 57). coils/secondary. had some spare cops at home so proceeded to change them.... no luck. took one of the "bad" ones nd replaced it with one that was working, and no spark/current. so my conclusion is: its not the coils that are bad. its probably the wiring. any ideas, suggestions to figure out what the problem is?

thanks!

 

N

n0v8or

10 Year Member

Aug 23, 2003

604

8

39

Rhode Island

Sep 30, 2009

#2

• Sep 30, 2009

• #2

Is your Mustang parked in a area where mice or other critters like to nest and chew on the wiring? Do you sees any droppings on top of the engine? Another Stangnet member reported a problem identical to yours and it turned out his cause was chewed wires.

 

U

usiskin99

New Member

Aug 29, 2007

26

0

0

Weston, Fl.

Sep 30, 2009

#3

• Sep 30, 2009

• #3

well, it just sits on my driveway overnight and its driven on a daily basis... i did chck the wiring visually, not extensively and didnt see anything obvious. i will look thorughly tom and will post findings. any other suggestions?
thanks.

 

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n0v8or

10 Year Member

Aug 23, 2003

604

8

39

Rhode Island

Oct 1, 2009

#4

• Oct 1, 2009

• #4

See:

*&%$#! Squirrels under the hood of my car!!! - Florida Gardening Forum - GardenWeb

It's also possible the harness is damaged where it rubs againsts something when the engine shifts during acceleration. When inspecting the harness, look for a location where this might happen.

Have you determined if just one cylinder is misfiring, or multiple cylinders?

 

K

Kilgore Trout

Fried or Broiled ?

10 Year Member

Mar 30, 2005

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Oct 1, 2009

#5

• Oct 1, 2009

• #5

My first thought after reading the original post was also mice...

 

G

GDTrumbo

Member

Jan 22, 2009

199

0

17

Nashville, TN

Oct 1, 2009

#6

• Oct 1, 2009

• #6

Some of the COP assembly's "boots" need replacing maybe? I had this trouble with my daughter's '00 Taurus.

GT

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Oct 1, 2009

#7

• Oct 1, 2009

• #7

n0v8or said:

See:

*&%$#! Squirrels under the hood of my car!!! - Florida Gardening Forum - GardenWeb

It's also possible the harness is damaged where it rubs againsts something when the engine shifts during acceleration. When inspecting the harness, look for a location where this might happen.

Have you determined if just one cylinder is misfiring, or multiple cylinders?

Click to expand...

The last digit of the code points to the cylinder with the problem. For an 8 cyl car, it would be cylinder 1, 2, 3, and 7. The last digit does not point to the cylinder number for 6 cyl and 4 cyl engines.

+1 on the wiring. It is a long shot to loose 4 COP's at the same time.

 

N

n0v8or

10 Year Member

Aug 23, 2003

604

8

39

Rhode Island

Oct 2, 2009

#8

• Oct 2, 2009

• #8

Perhaps your code P0357 is actually P0354 (4 and 7 might look similar on your scanner display). If that were the case, all 4 misfiring cylinders are on one side (passenger side). The common COP power wire goes first to the driver's side bank, and then via a jumper to the passenger side bank. A break in that jumper wire, or either splice, would disable all 4 COPs on the passenger side.

There is a radio noise suppression capacitor at the rear of each valve cover, connected by a single pin connector. If you have a voltmeter, you could disconnect the passenger side capacitor and check for +12V with the ignition On at the connector pin.

 

U

usiskin99

New Member

Aug 29, 2007

26

0

0

Weston, Fl.

Oct 2, 2009

#9

• Oct 2, 2009

• #9

ok guys, new findings with no positive outcome. i got cilynders #1,2,3, and 7 dead..... checked all the plugs to the cops from the main plug (upper left on passengers side on the firewall) and found continuty on all of them. didnt find any spliced, chafed or melted wires that could be shorting the circuit. next step to follow, check the computer. is there a way to check the computer for possible errors??? what else can i do? this is getting really frustrating. please help me!!!

thanks guys!!!

 

N

n0v8or

10 Year Member

Aug 23, 2003

604

8

39

Rhode Island

Oct 2, 2009

#10

• Oct 2, 2009

• #10

OK, I checked the wiring diagram more closely and discovered something interesting. Not all of the COP driver wires pass through the same connector to the computer. Two different connectors are involved. See the list below:

Cyl Connector Color
1 C104 Lt Green / white stripe
2 C104 Pink / white stripe
3 C104 White / pink stripe
4 C1007
5 C1007
6 C1007
7 C104 Pink / blue stripe
8 C1007

Do you notice something common to cylinders 1,2,3,7?
C401 is a 42-pin connector located near the firewall near the passenger side fender.

 

U

usiskin99

New Member

Aug 29, 2007

26

0

0

Weston, Fl.

Oct 3, 2009

#11

• Oct 3, 2009

• #11

is that connector the one that goes bolted on? because i checked that one (the one w the bolt) and im getting continuity from the pins all the way to the cop connectors so what i think is that the problem might be somewhere between the computer to the female part of the connector.

 

N

n0v8or

10 Year Member

Aug 23, 2003

604

8

39

Rhode Island

Oct 4, 2009

#12

• Oct 4, 2009

• #12

I checked my '03 and yes, it looks like the 42-pin connector is the one that is bolted together. I also noticed a nice big cavity below that connector that would make a great nesting area.

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Oct 5, 2009

#13

• Oct 5, 2009

• #13

Check for water in the spark plug holes

I thought of something else the check. In the 4.6 SOHC, the spark plugs holes point straight up. I have encountered misfire problems when water/antifreeze collects in the bottom. The fluid grounds out the spark causing a misfire/weak spark.

Try removing the COP and blowing the holes out with compressed air. Look down inside the holes because sometimes, grit turns into a kind of concrete at the bottom of the holes.