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Just put our Silk Green "MINIMNT" back together with the "repaired" Midlands (still has an axle leak) but now I have a driveability problem. Started working on this car back in December and it did not have this problem before this. When the engine bay is hot it will throw a P2300 and P2303 code and turn over at the right speed but not start. These two codes indicate "Ignition coil A circuit low" and "Ignition coil B circuit low". Coil is a "Screamin' Demon" coil that has been in the car for years with not problems.
First time it would not start was when we returned to the car in a grocery store lot after a short shopping trip. Engine caught for a second, then stalled and would not start. I went back later, had the hood up for a bit, then rolled it down the upper lot ramp to get it within reach of a tow truck. Second time I dumped the clutch it started. I suspect that it would have started with the starter at that point as I believe the engine bay cooled down enough.
Pulled the codes, then put in the OEM coil which I still had (after cleaning the posts with sandpaper). Car ran good with the OEM coil, and the Screamin' Demon coil at that point..
Another longer trip yesterday, car stalled out coming into parking lot for a medical appointment. While family member was inside, I hooked up OEM coil which I had placed in the boot. No start with OEM coil which I believe rules out either coil as the problem. Hood was open for the hour, when family member was done the car started and we drove away. Two blocks into our drive, car stalled out again and we had it towed home. At home, put hood up, ate dinner, came back out and the car started. Pulled codes P2300 and P2303 again.
Another member on here stated that they had almost this exact same problem and ended up sending their ECU away to SIA Electronics; SIA found and replaced a bad transistor. Any ideas on this? It's clearly a heat related problem which would definitely cause an ECU pproblem to show up.
And others have reported fixing this by havng the ECU repaired or replaced, not by subbing in a new coil.
Since you can pretty much replicate the issue I would diagnose the cause first, before sending off the ECU. Get the car up to temp and have it stall, pull the plugs and see if you actually don't get any sparks. If you do get spark, check if you are still getting fuel pressure into the rail. Then go from there.
I would also suggest, next time it won't start, pull the low voltage plug off the coil and test for voltage between the center pin and ground (with the ignition on).
If it's 0V then check the relay on the fuse block under the hood that is furthest toward the front of the car. Swap it with one of the others and try starting the engine.
Since the moderators didn't want to add my "how to" about my fix I will post an abbreviated version here. This problem continued up until last week, through the Midlands removal for a 6 speed swap and through all the other work I have done on the car. I did send the ECU off, came back with a clean bill of health. Put in new wires, problem didn't happen as often. Put in a new (Delphi) coil, car would not start, put old coil back in, car started and ran. Did the no start thing one day, put the Delphi coil in, ran fine. Did the no start thing again, put an old coil back in, ran again.
About a month ago it stalled out in a grocery store parking lot on the way to work, I cleared the codes and got it half running again and limped to work (on the highway! on two cylinders!), then had it towed to an independent shop. They diagnosed it as a bad coil by switching in a known good one and then replaced my old coil with an OEM one. Ran great for a few days, then wouldn't start when I was leaving work one day. Cleared the two above codes, then started. Stalled out again in traffic, cleared the codes, started back up.
I started the car when at home, wiggling and jiggling the electrical circuit for the ECU and coil while looking at the (so called) schematic for the car. Discovered that every time I jiggled the wires leading to the coil connector the car would stall and throw codes! That's why putting in a different coil worked most of the time- the connection was getting jiggled back into the right place, pretty much didn't matter what coil was in there.
The connector is a "Standard" S738 available at O'Reillys and Auto Zone and lots of other places. Says it's for a camshaft sensor but it's the right one for the MINI coil. The pigtail colors are different but you are smart enough to make the corrrect connections. My advice is to solder and shrink wrap the connections, you don't want to trust this to those crimp barrel things or just twisting them together with black tape!
Here's some pictures, let me know if you need advice on this or have any questions. If you are getting one or both of these codes jiggle the wires at the connector; if it stalls or throws a code you have an open and need to replace that connector.
Old connector prior to being cut off. Ignore tape on red wire, that was not the cause.
Wires cut (about 5 inches back), new connector ready to solder on. Soldered and shrink wrapped. This fits nicely in the heat protective sleeve that goes up to the connector. You can see that the connectors are the same. Here's the new connector (after being spliced on) on the new coil. The connector was a very tight fit on the coil and the red locking thing was somewhat difficult to slide across. Keep wiggling the connector on so you can get it completely on the coil and keep wiggling the locking slider until it goes over and looks like this. Otherwise the plug could work back out. And for good measure, here's the connector/pigtail assembly before splicing it on.
Hope this helps somebody else. I was about to park up my wife's R50 before I discovered the open connection in the wiring. Again, the problem was with the wiring and not just the seating of the connector so if this is happening to your car you need to cut the harness and replace with this pigtail.
