can you drive with a bad ignition coil

[raaizin]

After my recent experience with a failed ignition coil, assuming a total failure not intermitent. Would it be ok to drive the car. Or would it fall under category not at all.
The CEL light was solid NOT blinking so I would think it would be ok to drive it a few miles. Not sure if longer distances is ok. My primary concern would be unburned fuel contaminating the cat or washing past cylinder rings and causing damage there. What would be the longest distance that it would be safe. My wife has a 50mi commute each way and am thinking to replace all. I would hate to get the call the coil failed at work.

 

[Barkleymut]

I had a failed ignition coil on my wifes 2001 Chrysler van last summer. We were over 100 miles from home. I drove it really lightly on the way home but it made it no problem. Once I put the new coil in it was fine. I doubt you need to replace all of them, but it may be a good idea to pick up one of them and keep in your garage in case it happens at night and you have to have the car running by morning.

 

[Merkava_4]

Originally Posted By: raaizin
My primary concern would be unburned fuel contaminating the cat or washing past cylinder rings and causing damage there.


Just disconnect the wiring connector to the corresponding fuel injector to the cylinder with the bad coil and keep on driving. But you obviously gotta know with coil is bad and which cylinder it fires.

 

[Texan4Life]

It will be fine. I would change the oil after or shorten the OCI tho because of fuel dilution. My brothers car went for months with a bad coil pack. When he finally brought it in for me to fix it, the oil was black and smelled like gas.

 

[bvance554]

I thought the computer would shut off fuel delivery to a cylinder that is not firing?

 

[Merkava_4]

Originally Posted By: bvance554
I thought the computer would shut off fuel delivery to a cylinder that is not firing?


I wish!! When I had my misfire, which was cylinders 1 & 4 not firing, the fuel injectors kept on spraying fuel. I still don't know how much damage the catalytic converter sustained.

 

[Colt45ws]

Disconnect the injector.

Originally Posted By: Merkava_4
Originally Posted By: bvance554
I thought the computer would shut off fuel delivery to a cylinder that is not firing?


I wish!! When I had my misfire, which was cylinders 1 & 4 not firing, the fuel injectors kept on spraying fuel. I still don't know how much damage the catalytic converter sustained.


Depends. Heres a quote from the 2004 Ford OBD operation manual

Quote:
If a single cylinder is determined to be consistently misfiring in excess of the catalyst damage criteria, the fuel injector to that cylinder will be shut off for 30 seconds to prevent catalyst damage. Up to two cylinders may be disabled at the same time. This fuel shut-off feature is used on many 8-cylinder engine and some 6-cylinder engines. It is never used on a 4-cylinder engine.
After 30 seconds, the injector is re-enabled. If misfire on that cylinder is again detected after 200 revs (about 5 to 10 seconds), the fuel injector will be shut off again and the process will repeat until the misfire is no longer present. Note that ignition coil primary circuit failures (see CCM section) will trigger the same type of fuel injector disablement


Every manufacturer is different, but I would imagine that they all have something similar going on.

 

[Darwin1138]

If your car has sequential fuel injection, then it has the ability to shut down the injector of the misfiring cylinder. Otherwise it will hurt the catalytic converter.

 

[Vikas]

I suspect a vehicle which has coil per cylinder most likely have sequential fuel injection and thus the ability to turn off the injector. Whether they do it or not is the open question though!

Aren't all fuel injections sequential? I don't think there is manufacturer who is doing throttle body injection aka smart carburetor any more.