Hi. I'm a bit stumped and wanted to run this by someone else before buying a new computer.

I got an engine code P0357, and determined that I had a bad Coil over Plug (COP). I bought a new one, installed it and it smoked and burned within 10 seconds.

I purchased a new coil (COP) and spark plug, but I don't feel comfortable hooking them up yet.

I did a 12 volt light test on the input to this COP (#7 / G) and the light stays steady (no flashing) and is very bright. (before I put in the new coil that burned, the input was flashing).

Well, now that the coil input is steady, I know the coil won't work. This is computer controlled. Does this mean I need a new computer. Is there something else that can be replaced that actually produces the flashing 12 v signal or does it come directly from the computer? What is the computer called? Where is it located?

Thank you.

 

Anytime the ignition is on, you will have 12v constant on to the coils. The computer provides the pulsing ground that fires the coil. The computer is called the PCM (powertrain control module). Just a little bit of background info for you.

A bit of info about your truck wouldn't hurt, you know. What is it? What year? What engine? etc..
Good Luck.

 

Sorry. It's a 2001 Ford F-250 Super Duty V10 Dual Cab.. Automatic.

I checked the inputs to the coils while the computer was running. On the other coils my light is flashing. On coil 7, the light is solid.

It sounds like there is nothing between the PCM and the coil to pulse the ground. So, this sounds like a bad PCM? Are there alternative PCM's available that would allow power tuning? I saw some modules that piggy backed to PCMs. I was hoping if I had to replace the PCM that I could at least get something with some 'non-stock' capabilities (ie. better gas mileage).

Thanks again!

 

The problem started off with the truck engine dying while driving it. The PCM fuse had blown. I replaced the fuse, started the engine, and got code P0357. I tested the input into the #7 COP (engine running) and it was flashing, so I replaced the COP. Started the truck and in about 6-8 seconds the engine area filled with smoke and the 30A PCM fuse blew again. I replaced removed the power to the #7 COP, replaced the fuse and started the engine again. Engine running, the #7 COP input no longer flashes.

 

I don't remember off the top of my head what P0357 is. I would suspect a grounded wire first, before replacing PCM. Since it doesn't blow the fuse with the coil unplugged, I would check the ground side. Unplug the coil and turn the key on. Then check to see which pin on the coil connecter has 12v. This is your power side. Turn key off and measure resistance between the other pin (ground side) and ground. Does it have continuity to ground? If it does then you need to try the same test with the PCM unplugged. If the continuity to ground goes away then your PCM is likely bad. Most likely it still has continuity and there is a short to ground in the harness. One likely short could come from a remote start tach signal wire from that injector if it has one. Before replacing something like a PCM I would also do the test on another known good coil's wiring too. (Just to be sure, you know?)
I hope this helps you, I haven't worked at a dealer for a few years, so I'm not as sharp as I once was.

 

Thanks again for your help. I'll do the testing you mentioned and see how it goes. What is a "remote start tach signal wire"?

P0357 is "ignition coil G primary/secondary malfunction"

 

Found this for you


Fault code P0357 indicates a #7 cylinder coil circuit failure.

Possible causes are faulty ignition coil, faulty PCM, faulty wire from coil to the PCM, faulty connection at either the PCM or the coil.

A lab scope will be required to diagnose this problem. First, scope the secondary ignition system (coil output) and compare to other cylinders.

If there is no secondary output, verify proper power to the coil. If power is good, scope the Primary signal to the coil (coil trigger).

If no trigger is present, check the wire from the PCM to the coil.

If the wire from the PCM to the coil is good, replace the PCM as the driver has failed.

All of these are common problem. However, most common is a faulty coil.

OPERATION
The Coil On Plug (COP) works in the same manner as a standard coil pack. The COP Integrated Ignition (EI) system fires only one spark plug instead of two like standard coil packs. Since there is one coil on each spark plug, the coils will fire the spark plugs on the compression stroke only. Coils no longer fire spark plugs on the exhaust stroke.



Read more: ''97 E350, 5.4ltr. code read is p0357 ignition - JustAnswer http://www.justanswer.com/questions/...#ixzz11ju4qgMK

 

If you have a remote start on your truck (almost all trucks around here do. There is snow on the ground today.) The remote start needs a signal to tell when the truck is running so it can stop cranking. Most of the times I use a coil or injector wire.

 

With the truck in ON position (not started), the ground connector wire is grounded. The working ones are not.

It appears there are no power transistors between the PCM and the COIL. Is this correct? (I'm assuming none are needed because they are pulsing the ground and not the positive terminal).

I found two bolts under my dash that were holding down a black case over the PCM. Is there also a bolt coming from the engine compartment? I ask because the PCM won't come out. I don't want to remove the possible bolt from the engine compartment (if it's doesn't need to be) because it's surrounded by wires and it may be quite difficult to get back in.

Thank you.

 

Response is inserted into quote...

 

Thank you for your kindness and help.

 

Okay. I'm baffled and frustrated. Tonight I replaced the computer, the coil, and the sparkplug. I then tested and made sure that the terminal was working just like the other terminals and everything looked okay. I started up the truck. It sounded great so I took it out for a test drive. On the way home my truck filled with smoke and the new coil burned up again. I disconnected the terminal and checked it with a 12 v light. It appears to be working properly.

As I replaced all three components, I'm baffled by this. The only thing I can find as a possibility is that the pregapped spark plug had the incorrect gap (there was at least one reference on the internet to this causing coils to burn up).

Does anyone have any ideas?

Thank you.

 

Your wiring tested ok?
It is almost never the computer.

 

The computer definitely tested bad and doesn't anymore. Now, though, I'm at a loss as to how to fix it because there is only the computer, wiring, coil, and spark plug. The computer appears to work. The wiring appears to work and tests okay.

 

it has to be your wiring, you have changed everything else. I googled this

Coil is burning out because of execssive dwell. Something is making the coil fire all the time. Either there is a ground fault in the return line to the PCM or the D/A driver in the PCM is bad.

Start out be Ohming out the the COP return to battery negative (key off). Should be a very high value.

Next put a noid light across the COP. The light should flash while cranking. If not, suggest Ohm out the wire itself back to the PCM. If the wire path is OK, then it must be a bad PCM.