Stumbled and no more spark - 1985 318i

[nathan318i]

Howdy,

Driving around town the other day, the car started farting and sputtering. It died at a red light. Light turned green and after a lot of cranking, it fired up, and I was able to pull forward into the intersection when it died again. Yay. I pushed it uphill across traffic into the nearest parking lot.

I didn't have too many tools with me so troubleshooting for 3 hours only revealed that there was no spark, but plenty of fuel. I got it to fire up again for a few seconds but it quickly died. I haven't been able to get it to fire again.

Battery is fully charged and maybe 6 months old. Plug wires, plugs, and dist cap are a year old, but only have maybe 200 miles on them (I almost never drive my car any more, just ride the motorcycle). There is no spark on any of the 4 cylinders, nor when hooking a spark plug to the main power lead from the coil.

This is an L-jetronic 318i with Siemens/Telefunken ICU. There is no stomp test for my year/model.

I've tested the following:
Coil primary: 1.8-1.2 ohms
Coil secondary: 8,100 ohms
ICU large plug terminals 6/3 (I think): 12.2 V
ICU large plug terminal to coil terminal: Continuity (can't remember the small ohm value)
ICU small plug across itself: Continuity (can't remember the small ohm value)
ICU small plug, while cranking: 1.2V AC

I reached the end of the electrical troubleshooting chapters of the Chilton and Haynes (still looking for my Bentley). Each value is right about where it should be, except the coil primary ohm reading. I'm at 1.2 instead of 0.8.. but really, half an ohm would kill me? I find that hard to believe. I believe the Motronic has all the simple tests for CPS' and whatnot, so those don't apply to me.

Any ideas where to go next?

[MIKYZZ4]

Check all engine and battery neg-grounds for clean, snug connections,
also ECU grounds.

[Junglenut]

Check the spark plug and cool wire connections. Make sure the wires have a good internal connection to the mating component.

[T77911S]

12v on coil?
crank and check for spark, if no spark then try thre CPS

[nathan318i]

Since I hate dead-end threads with no updates, here's my update.

Today, I replaced the coil and it started right up. Runs fine now.

The weird thing is the book says the values should be:
Coil primary: 0.82 ohms
Coil secondary: 8,500 ohms

..and the old/bad Bosch coil are:
Coil primary: 1.2 ohms
Coil secondary: 8,100 ohms

..and the new/good Bosch coil are:
Coil primary: 1.2 ohms
Coil secondary: 10,270 ohms

So, technically, this new/good one is even further from the spec, but... further in a good way?