Fitting non-OEM ECU to K-jet MK2 16V Golf - do you remove old loom entirely

Hi,

After putting it off for ages due to nothing being wrong with the car in question and not having another car on the road to use I finally decided to make a start on disconnecting the old loom and removing it.

However, upon starting I can see that things I do need are also within the stuff I don't need. For example, the WUR and 5th Injector wiring which I will not need are heat shrunk within a loom containing the starter, reverse light switch, and oil pressure switches which I will need.

Do people just cut the plugs off unwanted items and pull the wiring through or just leave it there????

Ideally I do not want unused plugs every where but I also do not want to butcher the wiring looms.

I have also removed the dash today to make access to the fuse box much easier when it comes to the new ECU install.

Any advice please.

 

If the plastic sheathing is anything like mine, it'll be brittle and horrible and should break up and fall off without much persuasion lol.

Either that or split it down its length with a sharp knife, remove the cables you don't want and replace the sheathing with something else once the loom is how you want it. Get it running nice first, then tape the loom up

 

I'm pretty sure the wiring for the front wiper mechanism is also bundled into the engine loom.

My advice, based on what I did on my Megasquirt install, is to completely remove the 16V engine loom (including the wiring for sensors, starter, and wipers, etc. contained within it) and keep it intact and original. Remove also the ISV and controller wiring, again kept intact. Study these looms and understand what they consist of, and use them for reference purposes. Then, if you definitely don't need them later, they are something that you could potentially sell for reasable money, such as to someone doing a 16V install into a MK1/2 for example.

Build yourself a completely new loom from scratch. For stuff like the starter and wiper wiring, what I personally did was I took a number of fairly worthless engine looms from base model carburettor MK2s at the scrapyard and split the wiper wiring out of them. I then re-wrapped the wiper loom and kept that as a separate bundle. Same went for the starter wiring.

So, I ended up with a new Megasquirt loom as follows:



Installed alongside this as a separate loom is the front wiper loom (stripped from any old MK2 engine loom) plus starter wiring.

This all replaced the standard 16V loom which contained all of that.

 

Alternatively,

As I did with the Wolf R and a few others like Turbo Technic conversions, with a KR engine control system, the igntion ECU s removed along with it's wiring loom to the coil and other sensors. The TCI-H is left in place with the 7 pin connector and some wire tails. This will have to be cut off.

This means the senders for the ignition ECU and idle controller are removed from the engine, along with the 5th injector, over runcut off by the air flap and WUR.

The loom on the RH on the car can just stay unconnected or removed all togther.

Once the new injectors are fitted as well as the ABF type coolant sensor and air temp sensor, the SEM can be supplied +ve from the old black/yellow ECU supply in the rain tray area as well as the red/yellow fuel pump trigger on the same jack.
If the coil pack is retained with the 4 window dizzy the ECU should be able to read the 4 window hall pulse as engine speed and trigger the TCI-H as before. Depends on ECU though. Some SEMs are not configured for hall signals.
Fuel injectors are generally supplied +ve from the fuel pump output from fusebox and the triggers come from the ECU channels.

 

Thanks for the info guys.

Think I'm going to connect the new ECU/wiring loom with out removing any of the old loom at first (just disconnected) to get the car running.

I will then remove unwanted wiring but I have not made up my mind as to cut out unwanted wiring or remove it all and make now looms for the starter etc...
I've always been one not to cut up original stuff just in case I want to revert back but I'll cross that bridge when I come to it.

Cheers.

BTW
new ECU will run coil pack so no dizzy

 

If on 4 pole coil pack, then remove all TCI-h wiring and ignition ECU stuff. You should be left with a 2 pin jack with a black/yellow and a red/yellow wires, which you can use later.

Leave the KL15 wire lead (black wire) and the red/black wire tach wire on the engine control part of the loom as well. Those points can be used for coil pack supply and the tach input from diodes off the coil pack.

 

The ECU I'm using is a DTA E48 which has an output from pin 9 for the tacho although the previous owner did not utilise it by the looks of it (no wire connected in the loom provided).

I have seen the diode method from one of your other posts thanks but if I wire up the DTA then I shouldn't need to do it should I?
the coil pack I'm using is a SAGEM part No. 2 526 078 A which I got from a Renault Clio 172.