No spark from 2+3 coil

p38 4.6

Got a problem with coils, coil packs are numbered on the rail left to right
2+3 4+7 8+5 6+1

Had coil 2+3 melt so changed the coil packs... 2+3 melted again so changed 2+3 coil for another... theres no spark from this coil ive checked the wires leads etc any ideas?
Had a look thourgh previous posts cant find anything

The coil packs each have two wires connecting to the main plug am i right in thinking these two wires provide a 12v supply when the ignition is on? Does the ecu controll the power to the coil packs? if so would all coil packs be controlled by the same thing or would it be 1 for each coil pack?.. hope that makes sense cos i dont know what im on about

Sounds like the ECU is holding the coil on for too long, the coil is an AC device and should not be left on without the engine running, most systems cut the coil feed if the engine stops.

In your case it isn't, so check for anything else that has been added and could be feeding the coil in error. Shouldn't run properly if you have, but depends on when it is active and so on.

Might just be a connector issue, but it's an expensive game!

Peter

The coils on your vehicle are twin output and single primary, same as the 4-output Disco ones, except they have two per pack not one.

Each coil fires two plugs at the same time, what Rover call 'wasted spark' as only one will fire a cylinder that is on the power stroke.

The ECU grounds the coil, making and breaking each coil earth. The coil is fed with 12V all the time the ignition relay is on.

So, check that there is nothing on when you are stationary with the engine stopped.

Peter

Thanks for the info, is that the coil plug to loom connector (conector 5), So i need to check all connections first? could it be the ecu at fault? and if so are they all the same but need programming?

Just burn it

Sirus said:

Just burn it

Click to expand...

:doh:

nathan5346 said:

Thanks for the info, is that the coil plug to loom connector (conector 5), So i need to check all connections first? could it be the ecu at fault? and if so are they all the same but need programming?

Click to expand...

Mine is a bit different to your coils, but basically you need to check and see if the GROUND wire is actually grounded while the engine is off, which it should NOT be. The coil is fed with 12V through a fuse and the ECU provides the 'contact breaker points' for the coil via a transistor.

ECU's vary with vehicle, and some have different 'tunes' (programmes) to suit different engine spec's. The Disco II V8 ECU has tunes for both the 4.0 and the 4.6 North American Market engine.

So, to recap:

Find which connections are 12V FEEDS and check that they are all showing battery voltage or nothing.

Check which connections are GROUNDS for each coil, and see if the one which is burning out coils is permanently grounded. With the ignition off they should all be open circuit.

Pin 5 on Connector 5 is a system earth and will be earthed at all times the plug is connected. That is the connection that the internal trasistors use to reach ground. You need to check Pins 2, 6, 7 and 8, but Connector 5 must be plugged in to show any grounding of the outputs, or you could check between Pin 5 and the other four (on the ECU) with an ohmeter with connector 5 unplugged.

Peter

listerdiesel said:

Mine is a bit different to your coils, but basically you need to check and see if the GROUND wire is actually grounded while the engine is off, which it should be. The coil is fed with 12V through a fuse and the ECU provides the 'points' for the coil via a transistor.

ECU's vary with vehicle, and some have different 'tunes' (programmes) to suit different engine spec's. The Disco II V8 ECU has tunes for both the 4.0 and the 4.6 North American Market engine.

So, to recap:

Find which connections are 12V FEEDS and check that they are all showing battery voltage or nothing.

Check which connections are GROUNDS for each coil, and see if the one which is burning out coils is permanently grounded.

Peter

Click to expand...

Posted this on the thread in the range rover section


[[[[ Thanks for the advice, Spoke to RPI this morning and was told it will not be ecu related and that its definately a dead coil pack.... So to save spliting the packs up AGAIN i swapped the wires underneath to test the one that wasnt firing and swapped the ht leads to suit... Fired on all pots so swapped it all back round again and its running great as it should... conclusion? no idea maybe a bad earth/connection? cant fathom out why it burnt 2 coil packs out other than the above mentioned just hope it continues to run as it is... having the cats fitted this afternoon hopefully then book it in for MOT.
Thanks again for the help lads and the ones who PM'd ]]]]