coil on plug/wiring problems.. plz help!

usiskin99

New Member
Aug 29, 2007
26
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0
Weston, Fl.
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!
 
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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.
 
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.
 
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?
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.
 
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.
 
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!!!
 
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.
 
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.
 
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.