Question about an igntion coil

[formula driver]

I tested my ignition coil for a spark. Its getting a spark but it wont jump at all. It wont spark until its grounded. Does this mean I have a bad coil or is the weak spark that its putting out ok. The spark is blue it just wont jump. Please help. Thanks

[arsevader]

Re: Question about an igntion coil

I tested my ignition coil for a spark. Its getting a spark but it wont jump at all. It wont spark until its grounded. Does this mean I have a bad coil or is the weak spark that its putting out ok. The spark is blue it just wont jump. Please help. Thanks

How are you testing the coil for spark? The way to test an ignition coil properly is to measuer the primary and secondary resitance of the windings with an OHM meter.
Follow the procedure in the Bentley or even the Haynes for an explanation.

James

[formula driver]

I was without my ohm meter for the day thats why I tested it the way I did. I tested it today the proper way and its in fact bad.

[Bimmerfanatik]

I was without my ohm meter for the day thats why I tested it the way I did. I tested it today the proper way and its in fact bad.

Hey man, are you SURE this is a bad coil? I had it in a running car and it was working fine - I don't sell crap ;) If it does indeed test to be bad, let me know, I'll send you another one. I think I've got one around here somewhere.

[AdamF 88iS]

Re: Question about an igntion coil

I tested my ignition coil for a spark. Its getting a spark but it wont jump at all. It wont spark until its grounded. Does this mean I have a bad coil or is the weak spark that its putting out ok. The spark is blue it just wont jump. Please help. Thanks

The DME grounds it to activate spark. That's how the Motronic controls the spark advance.

[formula driver]

I was without my ohm meter for the day thats why I tested it the way I did. I tested it today the proper way and its in fact bad.

Hey man, are you SURE this is a bad coil? I had it in a running car and it was working fine - I don't sell crap ;) If it does indeed test to be bad, let me know, I'll send you another one. I think I've got one around here somewhere.

Yea... it was bad. I tested it and it was bad. I ended up buying a new one. Dont worry about it though. Ill continue to buy from you. I know you didnt mean to send me a bad part.

[formula driver]

Re: Question about an igntion coil

I tested my ignition coil for a spark. Its getting a spark but it wont jump at all. It wont spark until its grounded. Does this mean I have a bad coil or is the weak spark that its putting out ok. The spark is blue it just wont jump. Please help. Thanks

The DME grounds it to activate spark. That's how the Motronic controls the spark advance.

I tested the old coil and got a weak spark so I bought a new coil and the spark was jumping. So I put a plug in the boot and grounded it, no spark! I tested the coil again and no spark at the coil. Why would it do this. It was working fine one sec then not the next???? Could I have a bad ECU?

[jht3]

do you have a wiring schematic, a good one, for your car?

on my m3 there's an OBC code feature which cuts out the coil as a security feature. there's also a main relay on the firewall.