Look what I've just found

[Sussex Pete]

I'm praying that this is how it should be, but fear that I have just found, probably, the worst bodge so far on this car. This is the plug to the main ECU and came across this when tracing a couple of wires in this engine harness that didn't have a termination. When the wires in question appeared to go to terminals on the ECU for different operations I had to check further. The wiring was covered in insulation tape but underneath is exactly as in the pic and the ECU connector boot is split...

Now my quandary is whether to try and repair it or try an locate a good harness and just replace it. Why do I think that both of these options are going to give me grief?

[Austin-Rover]

Ouch! Quality bodge, that!

I'd try and replace rather than even attempt to improve that mess.

[Simon]

That is the best advice for sure!.

[kobe]

Ouch. Always a problem when someone else has "fixed" the wiring previously. Hope you manage to sort it out .

[Sussex Pete]

Thanks guys for the help! My problem now is that because the EPC doesn't show wiring harnesses, I don't know whether the sub harness to the ECU is common to other models or special to the Turbo. It will then be trying to find a suitable donor car or someone (like me!) who hoards wiring off old cars

Edit: Just found the harness on EPC (P/No HAM4109), but of course no one has that part on the shelf

[Simon]

It can be replicated if needed though, multi connector pins and sockets are available, mouldings are reusable and ECU plugs kits and shrouds are available (I have seen them somewhere). Wiring in the correct colour, cross section/strand count and current capacity can be bought by the metre too.

A proper non bodged fix can also be effected by splicing in new sections of wire to replace the dodgy bits using heat shrink sleeving to cover proper soldered joints, then tape the sub harness back up again.

I have seen some truly spectacular and highly dangerous wiring bodges in my time, as I guess we all have. At least you don't have any "kiss of death" Scotchlok IDC so called connectors in there, or any chocolate block screw terminals...

[Sussex Pete]

... At least you don't have any "kiss of death" Scotchlok IDC so called connectors in there, or any chocolate block screw terminals...

No, I found both of those elsewhere in the harness! I'm going through my stock of butt connectors (not pre-insulated ones lol) like there is no tomorrow, along with a significant length of heat shrink!

[Simon]

Oh my goodness, it gets worse...

Why do people mess wiring up so much? Wiring is the best bit, I love it but I have OCD about it.

[E_T_V]

Am I the only one who thinks that looks like OE screen bonding. The bare copper wire you can see should be the screen wire for the crank sensor. I don't think any other wires are screened in this way on the maestro.

[Sussex Pete]

Thats a good point Dan, as I thought it strange that the bare wires had a proper crimp on them, but couldn't see what they did. As I have just been quoted £75 for an ECU harness off an EFi, I think it is time I did a full wiring check on the one I've got. I'll report back as soon as I can confirm what's what!

[charliecosworth]

Think Dan has hit The nail right on the head

[Sussex Pete]

Think Dan has hit The nail right on the head

He sure has! Thanks Dan!

Only trouble is, now I've opened up the rubber boot, I find that there has been genuine bodging hidden away. Those two wires in the foreground pf the pic below are for the crank sensor. The tails connected to the plug terminals are linked to a pair of (now, unshielded) additional wires that I nearly put a new termination on. For future reference, both the crank and knock sensors are shielded and the shield wires are connected to a thin black wire that terminates on the multi-pin connector on to the main harness. So my initial prayer that these bare wires are how they should be, proved correct. The horror was hidden inside the connector boot! Now to sort out the correct wiring and repair the damage done

[E_T_V]

Ahh yes I forgot about the knock sensor. The wire shielding is connected to earth which the ECU is connected to aswell to minimise noise in the signals the ECU reads.

[Simon]

Ahh yes I forgot about the knock sensor. The wire shielding is connected to earth which the ECU is connected to aswell to minimise noise in the signals the ECU reads.

Which explains the braided shielding being connected to the black earth wire. The knock sensor, I'm told is a kind of microphone and as such needs to be shielded apparently as all microphones need to, again as Dan says to reduce "noise" affecting the signals.

I've replaced a connector on the knock sensor wiring before, but I've never had the ECU harness apart, so it's good to learn what's inside!

[Sussex Pete]

As a further update, I found that my ECU harness has a slate/purple wire connected to ECU pin 8 and terminates at the main harness multiplug - with no wire continuing on. This wire would be used for connecting to the Fuel ECU which tends to indicate that even this ECU harness was taken from and EFi car and is not original!