Hi all,
I've finally found the cause of my rough idle - 3 injectors on the A bank (2,4 and 6) are not working.
I tested each of the injectors with the ignition on and a test light probing the pins in the loom.
A bank looms 1,3 and 5 tested positive, however the other 3 gave me nothing.
I'd appreciate and help you can provide regarding how to find the cause of this issue.
Thank in advance,

 

Roger,

This lockdown has upset the CAT more than you.

Only real way is to unclip the loom in the bottom of the V, and carefully open it up. There will be a break in the feed wire somewhere.

The fact that loom travels out the B bank side of the V, and across to the radiator panel to the amp, is another area for damage.

NO quick fix sadly, just time, and repair/replace the wires. It is usually at this point I bite the bullet and just rebuild the loom, and raise it out of the V for longer life, or leave it there for the next 40 years once rebuilt.

 

Thanks Grant,
I managed to do some testing this afternoon, and I'm not entirely sure it's a bad wire.
I ran my multi-meter between the injector harness of one of the bad injectors and the corresponding pins on the loom plug - zero resistance on both the pins, so I tried the same on the loom wires between the loom plug and the amplifier - same thing, no resistance.

However... Using my trusty test light I am not getting current when I probe the loom plug and spin the throttle pedestal (on the pins that correspond the the dodgy injector).

Hmm...

 

Mmmmm indeed.

I have never had a bad amp, but I suppose they are out there.

That 2 4 6 is one bank of 3 as you know, and I will go looking later for the common whatever that may be the cause.

 

OK

OW (Orange/White)
OB (Orange/Blue)

Those are the 2 wires for 2 4 6 "A" Injectors.

I have attached a PDF of that section of the D Jetronic schematics. Hope it helps?

My one eye lost the plot trying to follow those lines.

 

So the rabbit hole goes deeper - initially I had only bank injectors 2,4 & 6 that weren't firing.
Not sure if my faffing about has caused a secondary issue or if it's related, but now b bank injectors 1,3 & 5 aren't firing either.
After talking with Grant Francis we thought it was likely an amplifier issue, however I'm wondering if the ECU could be at fault.
From my reading it seems the ECU sends two signals - one for A bank 1,3 & 5 and B bank 2,4 & 6, with the remaining signal sent to the amp to fire the other injectors - is this correct? If so is it possible the ECU is the cause of my problems?
All and any help/guidance is greatly appreciated.
Cheers,
Roger