v12 injector loom rebuild project

[Brakebuster]

as mentioned before , i have been in the process of getting parts together to rebuild the injector loom on my V12


this entailed getting the correct Bosch injector plugs, some heat resistant wiring, some cable sleeving and heat shrink and i also opted for some new 4 pin plugs to replace the original moulded 8 pin Lucas plug behind the offside headlight..

the cable is 16awg 200ºC 600v , silicone , the only place i could get it was from Hong Kong by the mtr........ and you need 10mtrs of red and 10mtrs of black , more colours would make it better for identification , but is not really necessary.

so , i now have all the parts , and i decided to start the project today ,
below are the plug components in order of assembly
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IMG_1688 by MyPix on Talk Photography

next is to measure out the runs ,

there are twelve injectors , with four firing circuits , long runs to A6 and A5 run back to the 8 pin connector , and also runs from B6 and B5 back to the 8 pin connector, the rest of the injectors splice into these looms with three injectors on each one ,

so , A6 , A4 and A2 , with A5 , A3 and A1 on the A bank ,
B6 , B4 and B2 with B5 , B3 and B1 on the B bank

schematic taken from Beranrd Embdens site

schematic3 by MyPix on Talk Photography

onto assembly
get a pair of wires measured from B6 to the 8 pin plug , and push over the boot , and the pair of connector seals ,
IMG_1690 by MyPix on Talk Photography

then strip the ends of the wires by about 3mm

IMG_1691 by MyPix on Talk Photography

then crimp on the pair of terminals, i decided not to solder as these are designed to hold perfectly well with just crimping , a standard automotive crimping tool can do this ,

IMG_1692 by MyPix on Talk Photography

then push on the plug so the terminal clicks into place, they will only insert in the correct orientation , so idiot proof ( i hope )
IMG_1694 by MyPix on Talk Photography

once the seals have been pushed home the boot can be pushed over the plug, i quickly found that by pushing the seal towards the terminal, the seal push in most of the way when inserting into the plug

IMG_1689 by MyPix on Talk Photography

This was done for all four main runs , then i made up the eight plugs with six inch tails, these will be soldered onto the main runs when i am motivated.........

i am wiring the loom as two separate systems, and the heat shrink and heat resistant cable sleeve will be added as i make up the looms , the main 8 pin plug is usually spliced onto these new looms, but i'm going a step further and replacing with modern sealed plugs , one for each bank , male and female , the female will be connected to the main wiring harness on the wing

IMG_1695 by MyPix on Talk Photography

when the engine is up to running temperature, i am getting ' some ' rough running, i am putting this down to the old injector loom being crusty , and i do have some broken plug connectors that are not fully secure, and i have already spliced salvaged plugs onto the loom in the past already , so its time for this upgrade

BB

[J44EAG]

terrific work, Vince.

Nothing so rewarding as making a nice loom or electrical system.

Very appropriate cable grade as well. That should last well. Decent cable gives so much more confidence in service especially as the loom ages.

What about the gearbox? Is that in yet?

Mike

[Brakebuster]

right

been a long time coming

yesterday i finished off the loom , all made to length and ready to install

this morning i have cut out my original injector loom

yup , nothing left in the car as i type, i have taken lots of pics, and they will follow later , the old loom is in about 20 bits ,lmfao

the new loom will run ' on top ' of the injectors rather than down in the hot engine V ,

i have also taken the decision to remove the main loom plug and replace with the same as in the pics above for the main connector, i think this will work better, and is one less splice ,

a few sensor wires and other wiring has also been moved out of the V and will also run on top and out of the heat

wish me luck this afternoon

BB

[J44EAG]

Nice one Vince.

High grade job and vastly better built and installed than originally. Tinned cable....nothing nicer. Mmmmn...yummy!

Mike

[Brakebuster]

this is what was left of my old injector loom
no going back now.....

the grey heat shrink indicates where i had spliced in new plugs in the past, but the wire was very crusty where is was against the engine , and most of the plugs were broken

IMG_1937 by MyPix on Talk Photography

SO I MADE THIS

IMG_1933 by MyPix on Talk Photography

when you have two similar plugs located together , its a good tip to alternate the male and female plugs, so when its removed, there is zero guess work as the what goes where

IMG_1934 by MyPix on Talk Photography


IMG_1935 by MyPix on Talk Photography

and the new loom all routed and plugged into the injectors

IMG_1940 by MyPix on Talk Photography

then i had to mess with this lot , lol

IMG_1941 by MyPix on Talk Photography

and it turned into this....

IMG_1942 by MyPix on Talk Photography

this is where the self doubt comes in ( yes i do get it , lol ) and i start asking if i have done everything right , ah well , lets turn the key and see, and Phew , first turn of the key and she fires, and it even sounds like all 12 are running , lol

IMG_1944 by MyPix on Talk Photography

i also changed the routing of the main loom, and took it away from the front of the engine, and took it to the right side and under the air box , as there is lots of room there, and i think it looks less cluttered that way ??

this was a very tricky project, and i would , if i had the chance buy a new loom for anything unto £250 if i found one, as the parts and labour for this would come to about the same if it was all added up , the cable and plugs alone, plus heat shrink and sleeving came in around £150 !!

and

i would also make it slightly differently , though mine is OK, it a Mk1 effort, and i could be more generous with the tails for the injectors, as the length disappears once the heat shrink goes on , but they all reached in the end

onto the next project

BB

[J44EAG]

Brilliant, Vince you are a true craftsman and should be very pleased with the result.

Well done my friend.

Mike

[Brakebuster]

a quick update

i have just discovered that the 4 pin connectors i have used to join my looms to the main harness will also fit the marelli style coil packs

i was reading other threads on the matter and as i had some spare marelli coils turn up the other day i thought i could try it out,

and its a perfect fit , you have to use the ' male ' section of the plug , the shorter one with the yellow rubber seal on the outside that fits inside the other plug

this is only for the marelli system , as this will not fit Lucas coil packs




so i can now replace my broken plugs on the coil supplies , as the ' holder loop ' has broken off ,

BB

[J44EAG]

It is quite incredible how plastics and cables disintegrate over the years.

A superb job, Vince and one that should give years of trouble free motoring.

Mike

[oldtimer]

Mike,
Having travelled all the way to Kemble to see it fitted into BB's motor, I have to say it looks a first class job - for what my opinion is worth - and a good breakfast too.

Those folks not attending don't realise what they are missing

Oldtimer