90 M30 535 eating Ignition coils.

[Neel]

As the title states, it seems my m30 E34 is eating ignition coils. I upgraded 3 or so months back to 8mm wires and the bosch type 3 injectors, I have within the past 7 months changed my dist cap rotor as well as plugs (yes they are gapped correctly) . So all of the parts that are directly related to the ignition system are newish and not old. When I changed my wires I ended up changing from the newer style ignition coil PART#: 12 13 1 742 925 to the old style cylindrical ignition coil 12 13 1 286 087. After initial change over within about 1 to 3 weeks the brand new ignition coil I had changed stopped working. I put the original IC back in the car and it fired up and ran, so I returned the part to FCP and received the replacement ignition coil and it has been running well until the past 2 days. Tonight I changed back to my original IC at work, got the car started and once I returned home I shut the car off and turned it back on after letting it sit for 5 minutes. (leading me to believe my IC is bad since I couldn't get the car started with the cylindrical IC)

Does anyone have any insight into why this may be happening, I did search and came up with nothing. I am going to check my engine ground when I can at work to make sure it is secure (I upgraded my engine ground to 2 gauge wire) and not causing a problem.

I'm not quite sure what else I should look into as a possible culprit, any and all useful suggestions would be great.

[Redfive]

Maybe it is the power feed to the coils. Perhaps it's got an issue and it's hurting the packs.
I've had coil issues, but that's with the turbo setup and the standalone computer. you have neither.

Sent from my VS988 using Tapatalk

[Neel]

No coil packs, ignition wires hook up to the ignition coil then to the plugs and the dist rotor cap tell sequentially what plug gets electric spark. But I know what you meant lol :P

Went to my car to turn it on after 2 hours of sitting and it fired right up.. I had to jump the car with a jump box the past 2 days in the morning so i could get to work, and the evening to get home.. looks like another ignition coil has bit the dust... oh well, time to send it back to FCP and have them send me another new one.

[shogun]

Have you checked the fusible links? Especially the one in the red wire going to the e-box, if that has haircracks, it can cause problems.
This is for the E32, but same for E34, Go to my website below, there it is explained,see in index under reference data, you have 2 fusible links under the rear seat. X6400 is the power post inside the E box. It feeds only DME loads.
ETM Page 1361-01 for M30 and 1367-00 for M70 + M30. Fusible Link A is 50 Amps.
That one is inline in the red wire and covered with plastic shrink and goes from the battery towards right side under the doors.Just follow the thinner red wire from the battery. Page 0670-10 Fusible B is 80 Amps. It feeds all the Rear Power Box loads. That one is usually behind the battery inside a black plastic box. http://www.bimmerboard.com/forums/posts/377728/ E32FAN commented:
If your Fusible Link A is intermittent, then the voltage at post X1540 will be low and fluctuating. This is easy to measure, at D100 Diagnostic Connector, pin 14. Pin numbers are shown on page 8500.0.20 X1532. And the numbers are molded into the connector.
This is shown on page 1360-01 in the ETM. http://shark.armchair.mb.ca/~dave/BMW/e32/e32_89.pdf Pin 14 is battery power, see here the pinout http://pinoutguide.com/CarElectronic...g_pinout.shtml

[ross1]

If you are certain the coil is the issue and the plugs are gapped correctly I'd say those wires could be the culprit.
Is the coil mounted firmly? Vibration can hurt them. Also too much heat, still in stock location?

[demetk]

Each wire should have close to 6k ohms resistance measured from end to end. The coil wire should have close to 3k ohms resistance.

[Neel]

thanks for the replies.. Im going to check this stuff out at work when I can.

[shogun]

this is from E32, but also applies for your engine:
M30/M70 ignition system data accdg to Bentley
Coil primary, coil code # 2051118335 terminals 1 (-) and 15 (+) resistance 0.50 ohm
Coil primary, coil code # 20510171101 terminals 1 (-) and 15 (+) resistance 0.37 ohm
Coil secondary, coil code # 2051118335 terminals 15 (+) and 4 (ctr. resistance 6.0 kohm
Coil secondary, coil code # 20510171101 terminals 15 (+) and 4 (ctr. resistance 9.0 kohm
spark plug ends 5.0+/- 10% kohm
shielded plugs 1.0 +/- 20% kohm
spark plug wires 0 ohm (approx.)
rotor 1.1 +/- 10% kohm

crankshaft position/rpm sensor:
540+/- 10% ohm

from workshop manual
distributor rotor 1+/-20% kohm
angled/shielded connectors 1+/- 20% kohm
spark plug connectors 5+/- 20% kohm
cylinder identification sender coil resistance at 20 degree C (68F) <1 ohm
pulse sender/crankshaft position sensor coil resistance 540 +/- 10% ohm
temperature switch for e-box cooling E32 750: switch on at 44 +/- 3 degree C, switch off at 36 +/- 3 degree C.