2006 Mercury Milan Ignition Problem

[Fishinguy40]

06 Mercury Milan, V6.

Sunday night as we were driving the car started to sputter and misfire. Check engine light began to flash. Luckily we were only a couple miles from home and were able to make it home. Pulled in the garage, popped the hood and could smell that familiar smell of burnt electronics. With the car running I unplugged each of the three front coil packs one at a time. I did this to determine which one was causing the misfire. I narrowed it down to the #4 cylinder. Shut the car down, pulled the coil pack and it was obviously damaged. It was bulging and cracked. Obviously overheated. Purchased a new one yesterday and installed it after work. Car wouldn't start. Turned out that the 15 amp fuse for the coil packs was blown. Replaced it. Fuse blew again. Unplugged the new coil pack and put another fuse in. Car won't start on 5 cylinders but sputters like its trying to start. Fuse still good. Plug new coil pack back in, attempt to start and fuse blows again. Swap new coil pack with another one to verify that it is not wiring or plug issue. Same thing. Car wont start on 5 cylinders and fuse blows when the new coil pack is plugged in. Return the coil pack and get another one. Car cranks, sputters and then fuse blows again. Pulled upper intake assembly and inspected the back three coil packs. No obvious damage.

Called a friend who is a retired Ford tech. He talked to another tech and described my situation. His friend said that if I have any codes beginning with 35 that I will have to replace all the plugs, all the coil packs and the PCM. WOW!!

I haven't had the chance to pull codes yet but I will tonight after work and update this post. The coil packs are $110 each and the PCM $800 - $1,000. That's not including the tow to a dealer to install and program.

I can understand where the PCM could have possibly been damaged when the coil pack failed but is there any way to test the coil packs individually? How about the PCM? I ohmed out all the coil packs and they all read 1.1 - 1.6 ohms. Even the bad one read that so obviously not a conclusive test. I hate to just replace everything if it doesn't need to be replaced.

[Fishinguy40]

I'm going to answer my own question. That's a first!

So I found out that there is a TSB about this. Though for some reason my AllData account doesn't list it. Only the superseded TSB. Seems its quite common for a failed coil to short out the PCM. Further research and it seems that I can get my current PCM rebuilt for $300 and a set of new coils for a little over $200 on line. That's better than the $2500 bill I was expecting.

[FF_205]

just did this in a customers car about a month ago, replace all the coils and retest, of still has a issue then replace the PCM, but they require that the new coils stay in there. The PCM provides the ground for the coils, called drivers, if there is a short in the PCM that is why the fuse keeps blowing. That may have something to do with the car not starting on 5 cylinders. I have never had a PCM sent out to be rebuilt but that may be a option, it would save you not having to program a PCM and your keys again