DTC P0351 - Ignition Coil "A". At the end of my rope.
Hey all, this is going to be a fairly length post, but then again, I've spent a VERY long time trying to fix this problem.
I'm sure many of you have heard of the issue with the wires breaking at the ignition coil connector. Well, this is just like that, except replacing the connector didn't fix the problem. Have a read through, if you have ANY suggestions on where I need to go from here, PLEASE PLEASE let me know.
I'm pretty much out of options... and I'm NOT the type to give up or ask for help lightly.
1. Symptoms starts
a. DTC: P0351 only
b. Heavy jerking under acceleration as car switched from 2-4 cylinders. Drops for ½ second, comes back, does it again
c. Rough idle, cylinders 1 + 4 not firing, tested with spark tester
d. Occasionally symptoms will persist, firing on 2 cylinders constantly
e. Quickly cycling the key on and off seems to alleviate the problem 80% of the time. Comes back a minute later, cycling the key again gets rid of it.
2. Spark Plugs
a. Testing old plugs, resistances 6000-9000, all good
b. Bought and tested new plugs
c. Installed new plugs
d. Reset MIL
e. No change
3. Plug Wires
a. Tested old wires, all under 7000/foot
b. Bought and tested new wires, spec’d ok
c. Installed new wires
d. Reset MIL
e. No change
4. Begin Factory Flowchart Diagnostic
5. DTC P0351, P0352, P0353: CHECK IGN START/RUN VOLTAGE TO COIL PACK
a. 11.52 volts, ok
6. JE5 CHECK FUNCTIONALITY OF SUSPECT COIL DRIVER (CD) CIRCUIT
a. Not done
7. JE6 CHECK SUSPECT CD CIRCUIT FOR OPEN IN HARNESS
a. Pin 26+58, both 3 ohms, ok
8. JE7 CHECK SUSPECT CD CIRCUIT FOR SHORT TO VPWR IN HARNESS
a. 0.01 Volts, ok
9. JE8 CHECK SUSPECT CD CIRCUIT FOR SHORT TO GROUND IN HARNESS
a. Not done
10. Replace Ignition Coil
a. Bought brand new ignition coil and replaced.
b. Reset MIL
c. Drove for 1 hour, symptoms returned, along with a P0351.
11. Begin additional diagnostics
12. Ignition Coil Harness
a. Purchased and installed brand new ignition coil connector (WPN-517)
b. Reset Mil
c. No change
13. Bypass harness
a. Cut wires to pins 26+58 appx 2” from ECU
b. Cut wires to ignition coil connector appx 4” from coil.
c. Ran 16ga. bypass wire to eliminate chance of intermittent fault in the harness.
d. Reset MIL
e. No change
14. Ensuring ignition coil ‘A’ was in fact dead
a. Swapped wires from pin 26 and 58.
b. Swapped plug wires from 1+4 and 2+3.
c. Reset MIL
d. New MIL, P0352, failure in ignition coil ‘B’.
e. The computer thought that ignition coil B was faulty, but it was actually hooked up to ignition coil A.
f. This meant that ignition coil ‘A’ was actually faulty.
g. Switched all wires back to original configuration.
15. Another Ignition Coil
a. In case some wiring fault fixed since step 10 had fried previous coils, another new coil was purchased and installed
b. Reset MIL
c. Drove for 1 hour, symptoms returned.
16. Reattached factory harness between PCM and ignition coil.
Thanks for reading. ANY suggestions, no matter how seemingly unrelated, would be useful.
As no old forum regulars have jumped in here, and as I'm a new Duratec guy, my assistance is going to be limited, and some of my comments may appear obvious, but...... the problem appears to be a loss of the "trigger" (the coil driver circuit) to the one coil. It also seems to be a "heat soaking" thing going on here and it's interesting that "cycling" the IGN. affects this issue. Do you know if the power transistors are incorporated in each coil or are they in the PCM? Is there a relay involved? You don't appear to have accomplished the Check Functionality of the associated Coil Driver circuit, going by your "not done" note. If that's true, then that's where you have to go I believe. I hate to suggest it, but could the root cause be the PCM?
JE5 tests the coil pack by hooking up a test lamp between the 12v pwr wire and the grounding wire on the coil. I already had a new coil pack that I installed right after completing all the harness wire tests, so I skipped this step as it wasn't needed. The only conclusions coming from a negative result to JE5 is replacing the coil pack, which I did.
I'm unclear on the effect of "heat-soaking". Are you talking about heat soaking of the coil itself, or another sensor?
As for the transistor location... I'm honestly not sure. Doesn't seem to indicate in any of the information I have either.
I figured the key cycling was the big issue here. Not sure what it means... but it feels important.
Thanks very much for spending some time reading and for the suggestions, it's much appreciated.
a friend just had this problem and replaced the pigtail. the problem persistes so he replaced the coil, it was still no help. finally after testing the wiring with an ohm meter to ground it was found there was still a bad wire to the coil. after pulling off the conduit on the harness they found the wire was shorted to another further down than where they spliced the pigtail. repaired this short and hasnt had a problem since
The heat-soaking is in reference to an electrical component sometimes failing after a certain period of operation, but working perfectly up to that moment. Transistors for example sometimes fail after getting "hot". I wasn't thinking of the coil because you had already changed it out. I'm just wondering if some (other) electronic component in the "trigger" circuit (which includes internal PCM circuitry) for this particular coil is failing. Because you have spark from the other coil, it at least is getting the ignition signal ("trigger") from the PCM, but I'm wondering if your "problem coil" for some reason stops getting it's PCM ignition signal after a period of engine operation. Is there an Ignition Signal code for this car or just the "coil" codes that you've stated? As I mentioned above because the other coil is firing I think the PCM is getting all the normal, required sensor info, but is there any troubleshooting reference to the Crankshaft Position Sensor? Is there a condensor in the coil power supply circuit? With the engine running have you "yanked and pulled" at all the associated electrical connectors and harnesses?
Here's an update to all who are interested.
In 2 hours, this car is going into the Ford dealer. (shudder)
I've never owned a car that I've taken to a mechanic, nevermind a bloody DEALER. But I've got no more time to spend with this problem.
Once I hear back from the dealer, I will post ALL the results here, as someone with a similar problem may stumble upon this thread in the future. Thanks to all who gave suggestions, I'll let you know.
Krike! Not a good day for "spark" issues.......there's a couple more above now. Yes, for a multitude of reasons, dealers are scary places. Good luck and let us know what happened.
My 2000 Focus with Zetec exhibited similar symptoms this afternoon. Acted like it was running on 2 cylinders. Did it twice for a few seconds about 30 seconds apart when stopping at stop signs in a residential area. MIL did not come on, but scan tool showed P0351 when connected later.
What's the most likely failure mode when this code is logged?
BTW: 60k miles and about 7 years old.
My 2001 ZTS has 150,000 miles on it and have similar symptoms. It keeps burning the coil pack. 3 as of today. I put a new one on and it runs fine for 1 to 5 minutes and sputers and dies and will not start again. Followed by the smell of SULFER. I just noticed the wiring harness was melting on a EGR pipe that runs along the side of the head on the drivers side. i will fix the burnt wires tonight and get a new coil tomorrow. cross your fingers. I'm hoping it doesnt burn up the 4th coil.
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