1998 Disco 4.0 Been having misfires and code 1316...so removed the coil pack and tried taking it to AutoZone for testing...but no test available...I asked him to check the ohm resistance..and he tried by taking one end of meter inserting it into the coil and the other end touched to the wire...could not get readings that way....but could only measure where the two wires go in under the plastic protective cap. He measured around .35 on each of the coils...with only small variance and I read where primary resistance should be between .4 and 1.2...is this the source of the problem? Any reason why all would be lower value readings meaning higher resistance than normal?

 

Any electrical gurus here? Can help?

 

Why do you think this is a coil issue to begin with?

 

Not sure...but the ohm reading was around .35 on each Coil Pack where the wires connect to each coil...if coils wear out does the resistance go like that? This coil pack looks mighty old...and well used...

 

I have an extra working coil pack so I went out and measured it. I got about 1 ohm on each coil. These coils generally last for a long time so I'd be surprised if something was wrong. Misfires can be caused by lots of other things such as O2 sensors, CATs, vacuum leaks, fuel pump, fuel pressure regulator. Check for any codes with a scanner, check for vacuum leaks, and fuel pressure.

 

Any other codes? Any other noticable issues? Have you ever done plugs and wires? cleaned maf? replaced O2's? Checked fuel pressure?

I have seen P1316 end up being sticky valves as well. First thing I would do is vacuum test.

 

Nothing is forever....but my question is do these coil packs deteriorate in the way this one is...the reading being .35 ohm when the normal is .4 to 1.2 (that was what the specification was for at AutoZone...yours is at 1 Ohm...which means it is in spec...

I did change plugs, wires, fuel pump, maf switched with another one...haven't done fuel pressure or FPR....as I have no gauge to read fuel pressure...

I really need to know if .35 is typical of failed coil packs...I think they are not bullet proof and they do eventually go to coil pack heaven...

 

no other codes.....just the one 1316 on the generic code reader.....

 

It's really hard to break a sealed coil of thick copper, but maybe if the grounding was poor, or the plug gaps too wide and placing too much stress on the coils. I researched coil pack failure and didn't find much when I was diagnosing my own misfires. I replaced the coil packs only the find out they were fine. Hence why I have an extra set

 

I believe you are looking in the wrong direction. 1316 is just an excessive emission misfire which can be caused by lots of issues.
I would not throw out your coil till you do the specific test called for in the Rave CD.