MK1 Golf Motronic ECU Wiring
#1650711 (In Topic #232929)
Red/white wire from lambda sensor connects to where?
6 wires coming from the Motronic ECU loom, these are:
Red wire - I assume this is the power to ECU from mk1 fusebox? Connects to pin E14? Or to battery (or somewhere else!?) and need to add an inline fuse?
Purple/white wire connects to where? Is this needed?
Brown/red and green/blue wires connects to where? Are they needed?
Yellow and grey/white wires connects to where? Are they needed?
Thanks in advance for any help anyone can give me on this!
There has to be someone out there who's running motronic injection…..surely!? Lol
So ECU and loom are in, most wires connected up however I have a couple spare so far, these are:
Brown and black/white - I'm sure this is for the thermotime switch however as mine is a 2.0l 19v 9a I believe they didnt have the thermotime switch fitted
Green / yellow and black / white - currently not sure what this should connect to, thinking I dont need it!? Need to check the wiring diagram on this……
Because the above are connected to 5th injector, ISV and the like via the black/white wire I'm guessing I'll need to remove the above connectors and close the circuit to ensure the correct signals are sent back to the Motronic ECU - Any guidance here before I do this would help greatly!?
red - permanent live, P spade
purple/white - chase it back to source in ecu loom, cant see in my golf diagram but suspect it may be ecu mpg signal to late corrado clocks
Brown/red - might be earth for ecu, from pin 34?
green/blue - cant see on my diagram, chase to source
Yellow and grey/white - diagnostics port 15 and 7 respectively
brown & black/white plus Green/yellow & black/white are both for carbon canister system, so they can be binned off
Ok so I've wired everything in and connected everything up, however the hazard relay is going nuts when I switch it on and the fuel pump relay doesn't seem to be working now……any ideas what might be the cause of this?
Could this be a grounding issue somewhere!? 🤷♂️
I've checked every fuse and none are blown.
When I turn the key there is no 'click' just a constant drone
you can see the white block just above fusebox in your pic and the claw to the left. the claw should be screwed above the fusebox by the way, where it is will get in the way of the carpets and could get knocked by passengers
you also need a 17, 18 or 100 relay in slot 8 below the fuel relay for the wipers, blower motor and some accessories
Also put relay 18 back in, no idea why I took that out in the first place!
Turned the key and I'm still getting the same noises as before.
I started checking various wires with a multimeter and found there was no power to the starter motor, traced that back to the coil which I then traced back to the ignition control unit. There was power at the 3 pin connector but nothing coming out of the other end so it's going to be fun trying to find a replacement
I guess there still must be a dodgy earth or connection somewhere for the hazard relay to be making all that noise still!?
next check your ignition switch, should have 12v at the red wire, ignition live at the black. the black wire from the coil is powered direct from the switch via fusebox, but the negative side of the coil is pulsed by the spark module so you need to check between coil live and battery negative
make sure the battery is decent as well
Black wire to ignition switch has power when the ignition is switched on.
When I started I didn't have power at the coil, starter or ignition control unit, I swopped a couple of wires round then back to where they were and now there is power there 🤷♂️
I now don't have any power from pin E14 which I have used for the fuel pump live and lambda sensor when the ignition is on.
And the battery isn't the best, I have a new one coming, should be here tomorrow
I think I'm going to map out where all the wires run that I've installed to keep track of everything and see if I've gone wrong somewhere……its going to be something really simple and stupid I just know it.
From ECU to:
Ignition control unit (scuttle): green, black, brown
Knock sensor x2
A third solid black wire similar to knock sensor connects to HT lead (detects pulse) which connects to dizzy cap
Potentiometer (airbox): grey/red, brown/white, grey/green
Pressure actuator (airbox): red/white, brown/blue
Throttle switch: grey, brown/grey, blue/black
Lambda sensor: brown, black and purple wires (both within black outer cable), red/white (to pin E14 on mk1 fuse box) E14 pin currently no power when ignition is on
Coolant temperature sensor (side of head position nr. 3 on below graphic): brown/white, purple/black
Hall sender (beneath dizzy): brown/white, red/black, green/white
White wire to ISV, black/white wire to 5th Injector (cold start), black/red wire back to ECU (all connected in a loop)
Yellow/green and brown believed to have been connected to carbon cannister not connected to anything currently
x2 brown wires to battery negative
Brown/red wire to battery negative
Black wire to coil (terminal 15)
Red wire to mk1 fusebox (p-spade)
There's also a blue/white and red/yellow wires which I believe are related to temperature sensor on side of head (position nr 5 on below graphic), I connected these together and attached them to where the MK1 coolant temp. wire goes to however this seemed to short out so both are currently not connected, only the MK1 temp. wire is connected here
From Ignition Control Unit to:
Coil: blue wire (terminal 1), red wire (terminal 15)
From MK1 Fusebox
Pin E14: red wire to fuel pump live terminal (currently no power when ignition is on) also red/white wire to lambda as above
All other wiring in terms of permanent/ignition live, high and low oil pressure wiring and oil temperature wiring, mk1 temp gauges etc. as per original conections/layout
If anyone has any suggestions or idea as to where I've gone wrong or if I've missed a connection somewhere I'm all ears as this is getting a little frustrating now! Lol
coolant temp is next thing to check. you cant short 2 wires into the same sensor, and do you have the white 2 pin sensor the 9a ecu needs? its the same one as ABF.
the sensor wires for that white sensor should be purple/black and brown/white though according to my diagrams… so chase those 2 wires you have back to source. only place I can see a blue/white on ecu loom is for vehicle speed sensor and only red/yellow I can see is fuel relay earth trigger which should go to D/13
The 2 wires connected to the white 2 pin sensor go straight back to the ECU and came from that sensor as I labelled it as I was removing the engine from the Corrado. Typical these differ to your diagrams 🤦♂️
Ah ok, so if I connect the red/yellow wire to pin D13 then that should spin up the fuel pump then…….that would make sense why it currently isn't working
I assume the other connections are ok? I wasnt sure if I needed to connect the ISV and 5th injector to anywhere else other than to each other and back to the ECU?
I'm guessing the weak battery isn't helping matters and I've still got either a dodgy earth or a short somewhere which is why the hazard switch is going nuts and the starter isn't cranking?
with blue/white and red/yellow chase them right back to source so we can be sure what they are. but yeah if ecu red/yellow fuel relay trigger to d/13 isnt connected the fuel pump wont work, you ashould have a 67, 80 or 167 fuel relay slot 2. blue/white if speed signal you can ignore
isv should be wired straight to ecu, as should the cold start valve. they both have a common brown/white which hare tapped together then off to ecu, the other pin straight from ecu if that makes sense.
weak battery might be the rood cause yep
Both the Blue/white and red/yellow run to the ECU so I'll connect the red/yellow to pin D13.
Yep I've got 167 relay in slot 2, also I have 67 as an alternative, not sure if one is better than the other?
Blue/white wire I will ignore
So the wiring is: white wire from the ECU to the ISV, then black/white to cold start valve then red/black wire back to the ECU so a continuous loop - do I need any other wiring here?
Still waiting on new battery to be delivered but can wire in the fuel relay earth trigger in the meantime
Thanks so much for all your help btw, really appreciate it!! 👍
cold start has black/red to ecu pin 16, isv white wire to ecu pin 17, and both have common black/white to fusebox ignition live. you could use D/2, D/7 or G spade 2 or 5
ignore what I said about brown/white back to ecu, that was rubbish
Red/yellow fuel relay trigger to fusebox pin d12/13
Blue/white speed signal to fusebox d2? Or just ignore this?
Run black/white wire from ISV/cold start loop to either d2, d7 or G spade 2 or 5
Replace the battery then see what happens….🤞
I owe you a few pints all the help you've given me!
I've got life back in the fuel pump but the fuel pump relay is going nuts. I've tried a 167 and 67 relay and they both do the same thing.
When I switch the hazards on that relay also goes nuts (like the video I posted previously)
When I turn the key there is no crank/click/turnover whatsoever
I'm at a bit of a loss to be honest, I can only assume I've either wired in something incorrectly, I've got a bad earth or a short somewhere!?
Any other ideas what the cause could be?
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