ECU Trouble

[LPStandard]

Recently I have been having ignition issues with my 318. It has the m42. I discovered that coil 4 was not firing. I tested the plug wires individually and they were all working. I replaced coil 4. Still no spark from coil 4. I swapped the plugs from coil 4 to coil 3 and tested for spark. This time coil 3 did not fire but coil 4 was.

Using a test light and a DMM, I tested the leads to coil 4.

+12 is good
GND is good
Continuity between pin 51 on the ECU plug and the plug to coil 4 is good.

Stomp test results in a 1271 code. This is the only code being thrown.

Correct me if I am wrong, but that means that coil 1 has a fault right?

Coil 1 works fine. Coil 4 does not. Am I wrong in thinking that this is a fault in the ECU?

Any help is appreciated.

[1991318is]

Recently I have been having ignition issues with my 318. It has the m42. I discovered that coil 4 was not firing. I tested the plug wires individually and they were all working. I replaced coil 4. Still no spark from coil 4. I swapped the plugs from coil 4 to coil 3 and tested for spark. This time coil 3 did not fire but coil 4 was.

Using a test light and a DMM, I tested the leads to coil 4.

+12 is good
GND is good
Continuity between pin 51 on the ECU plug and the plug to coil 4 is good.

Stomp test results in a 1271 code. This is the only code being thrown.

Correct me if I am wrong, but that means that coil 1 has a fault right?

Coil 1 works fine. Coil 4 does not. Am I wrong in thinking that this is a fault in the ECU?

Any help is appreciated.
Considering it switched to coil 3 didn't work when you switched them, I'd doubt its ecu. I'd switch them all around and try a new set if its still jumping around. Also check all of the grounds and all of the powers.

[LPStandard]

I didn't switch the coils, I switched the leads going to the coils. So from the ecu's point of view coil 4 was coil 3 and vice versa. The result was coil 3 (coil 4 as far as the ecu knows) not firing and coil 4 (ecu3) firing.

All powers good and all grounds good.

All 4 trigger wires have continuity to the correct pins on the ecu plug

[nicknikolovski]

You should replace all coils at once.

[LPStandard]

You should replace all coils at once.

I know. But I am trying to save up for school in september so I couldn't justify 4 coils.

[nicknikolovski]

That's strange, what you mentioned above because if swap any of the coils to a different cylinder, the engine will misfire straight away. For a new set of coils your looking at $170 and a set of ignition leads $130 both from pelican parts or you can try BMA which may be cheaper with the M42CLUB discount.

[LPStandard]

I was swapping the leads with all of the plug wires removed from the head. Simply to test for a change.