PLEASE HELP ME 1997 LAND ROVER DISCOVERY 4.0 COIL TRIGGER

Rebuilt Engine all new part from Atlantic British , No One has a answer, PLEASE HELP. Engine starts up first try runs great at idling . the Disco has 4 coils each coil fires 2 cylinders the ECM fires all 4 coils at idle , THEN all at one the ECM only fires 2 coils which runs only 4 cylinders, YEP no one Knows the answer , if the crank sensor was not working it would not trigger any of the coils , and cam sensor is for injectors only , also new ECM same problem , TAKE THIS CHALLENGE and i will be very impressed , signal looks good with my scope when its working, ALSO NEVER A CHECK ENGINE LITE

is there any way you could try different coil packs?? They could be be breaking down when heating up!!

Mark Piercy said:

is there any way you could try different coil packs?? They could be be breaking down when heating up!!

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Yep got new ones , same problem

mitchell offutt said:

Yep got new ones , same problem

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Good thought Mark , haven't tried to disconnect 1 of the 2 while it's running and read the signal , try it tomorrow

just try pulling a plug lead while its running, that'll narrow tour search by half. Also check your coolant sensor and lamda readings before and after the cutting out! I take it you've done all the physical checks and are looking towards electronics. Could there be a chance its the ecm and what happened to you old ecm.

The Ecm I replace , I have always had the same issue, with both, I will test my trigger signal with it disconnected from a coil with my oscilloscope and see if their is a current load problem and and also scope my crank sensor and see if I am losing a pulse

From what I understand the crank sensor is the only input signal that effect s the coil trigger and the camshaft sensor triggers the injectors which are working fine , it runs great on a start up firing on all 8 cylinders then loses the coil trigger on 2 coils then is running on 4 cylinders, while injector are running on all 8 causing it to run rich and foul the spark plugs

right then buddy, get this posted in the discovery section, you'll need more input from other disco owners with previous and maybe the same experience as yourself! Good luck

Found a bad solder joint on my ecm re solder and give it a try, its going to my output haven traced it to confirm out put to coil trigger

fingers crossed, check them all, time consuming but it'll rule out anything else possibly contributing, use a good strong light and a magnifying glass.

No luck ,

damn, you need to go and make a physical check of the wiring loom around the engine, to be sure nothing has rubbed through!