My '94 E320 just started to misfire.
I checked the HT from each of the 3 coils using a clip on timing gun and found that there is no output from the rear coil to plug 1.
Swapped the coils around, fault stays with whichever coil is at the back.
Same with the HT leads (1 & 5).
So, I think the may be a fault with the feed to the rear (6) coil.
How can I check this?
The feed, presumably, come from the ECU. Is there any way to trace this fault back?
Or, have I missed something simple?

Change the plug connectors under each coil ...all 3 of them

..and check the wire harness for flaking insulation..

Archieves search

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Thanks for the reply.
I swapped the coils with the connectors.
The wiring harness is not flaking (I'm aware of wiring harness problems).

I can only think that there is no input to this coil but I'm not sure how to check this or trace it further back.

Coil is hot 12v all the time ..ecu is a switched ground.
First try would be to change the plugs on 1 and 6 . A bad plug will do the same as a bad connector.. and see if you have 12v to that coil.

I don't understand your comment asbout 'Same with HT leads 1 and 5
???

Hi Arthur,
I think we're getting somewhere now. The Input to the front two coils is 12v but the rear one is only 6v. Measured with a very crude analogue voltmeter, coils disconnected.
Any idea why the rear one would measure lower?

Seen that before
Cause was bad connection in harness where the three wires branched off the main feed to each coil.