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[Talk_Converter]

My 2.5 V6 was running poorly and the plug wells filling with oil. Replaced all gaskets and O rings, cleaned breathing system, replaced plugs and HT leads and then found crack in Dis Pack so replaced this as well. Still not running as good as it should but computer diagnostics said all was fine. Found no spark on Pots 2 & 5 and so tried the old Dis Pack, still the same. Dis Pack connector has 4 wires, Black (common), Grey, Yellow and Red. A signal is present on Grey and Yellow but not Red. Traced wiring back to ECU and all OK. So is it the ECU or perhaps one of its inputs like the flywheel sensor, assuming it has one. Any thoughts? No fault codes from ECU, it says all is fine.
Anyone have a spare ECU I could buy/borrow to prove where the fault is?
Any help/suggestions welcome, Les

[TheBoy]

Shame you are not closer - you could borrow one of my ECUs/immobiliser ECU/transponders....

[Talk_Converter]

For an update on this, my mechanic tells me it is pin 1 of the Dis Pack connector that is missing a  signal. The car evidently starts well, idles nice and drives fine with both leads disconnected from pots 2 & 5. I have to ask myself how long this fault has been there and not noticed. I thought the car was pretty quick, goodness knows what it will be like if we can get the HT on every pot. Strange that nobody else has had this fault or maybe, like me, they don't know they have it 

[Omegafantasy]

I think you'd notice if one third of the engine was gone, at least when driving  :-?

What does the spark plugs look like now?

[Talk_Converter]

Cannot say about the plugs as the car is not with me but with a friend some miles away.
I have read somewhere that there is an amplifier unit between the ECU and Dis Pack that can cause failure of Dis Pack pairs to work. Can anyone confirm this?
If true, do you know where it is located?

[Omegafantasy]

There's no amplifier between the ECU and DIS-pack. The negatives from the DIS-pack connects to the ECU while the common positive is supplied via a relay (as are the injectors, lambdas and more).

[Talk_Converter]

Many thanks Omegafantasy, looks like another ECU then, would have made a bit of sense though to have had an external driving pack. Probably a power semiconductor in the ECU has gone down.

[Omegafantasy]

You're welcome 

I'm curious as to exactly how the ECU is inside, looking for a schematic. I have some issues with a driver myself (although unknown driver (code 136)). Replacing standard components can't be that hard so you might be better off repairing the ECU instead of spending a lot on a new unit? If it is discrete semiconductors (which I think output drivers like that would be), it shouldn't be very critical using the same part, they're only switching..

[Talk_Converter]

OK, please bear with me folks as I am communicating with my mechanic over miles of land line. I read on this Forum that the Omega ECU is pretty robust so I decided to take this as gospel and get my mechanic to do some further tests. I asked him to connect a small 12V bulb between the Diss Pack connector pin 4 (12V) and pin 1 and simulate via his computer software firing on that line. The bulb lit and he conducted the same test on pin 2 and then again on pin 3. Each time the bulb lit and has restored most of my faith in the ECU. Re-connecting the new Diss Pack, it still refused to spark on pots 2 and 5 and even failed when he drove the same input from a known working ECU output. This pointed to the new pack being faulty which was further reinforced by substituting the old original pack which now seemed to drive pots 2 and 5 but not 1 and 4. So the fault appears to be both Diss Packs so we are going to replace the new one under warranty and try again.
It's crazy to think that my car was running reasonably well on cylinders 2,3,5 and 6 with one pack and cylinders 1,3,4 and 6 with the other. Hopefully we will soon get the car sorted without having to change the ECU, I thought that it would be a good idea to describe the simple bulb test as it may help others.

[Omegafantasy]

Sounds like he has done a decent job with that one, and a great idea for sure, but please, consider this too (just to confuse you more  )

The DIS-pack has a considerable smaller resistance than a normal small light bulb.
DIS pack primary coil resistance: 0.45-0.65 Ohms
5 Watt light bulb: 28 Ohms or so.

With that in mind, your ECU have to sink about 24 amps at 12V with the DIS-pack and about 0.5 amps with the light bulb. A bad connection or a faulty driver in the ECU might be able to sink the load with a bulb, but not your DIS.

A better way to measure this is with the bulb connected together with the DIS-pack, but might be tricky.

You could also measure the resistance in the different DIS-pack primary windings..
Pin 1&4: 0.45-0.65 Ohms
Pin 2&4: As above
Pin 3&4: As above

Hope this helps a bit, and sorry for any confusion