fueling

[clipperjay]

it's about 3 degrees in Glasgow, where would I find these grounds and how do I check

Well the lower the temp higher the resistance so you are in spec!
All grounds ones near the ECU one from body to battery to gearbox!
One on the coil body!
Or a break in the ECU loom touching a ground causing issues.
I think everyone has commented on the most likely problems on here, but from the solutions you have tried already its go to be simple like a bad connection somewhere.
Guess you could start checking resistance on each ECU loom pins on a good car and then compare it with your problematic golf?
My Hall sender caused massive over fueling and broken injector loom feeder on mine, but you have already said you have changed it already???

I tend to change over any visible earths with new braided items and cables I even taken a Corrado battery loom because the cables are thicker and better insulated than our old Mk2's. Stick some grease over exposed cables and remove out any oxidised cables especially when they go green in colour.

[Craigwilson]

well my earth cabled are recently replaced because I came across my starter failing due to a broken earth lead, tommorow I'll give that a shot by running tests on my dads 8v then compare it with mine (the broke one)

[clipperjay]

This pretty sums up what we have covered mate?

[Craigwilson]

doesn't have an O2 sensor does it?

[clipperjay]

No it wont unless you have a CAT which is unlikely. It was a tick check off list for you 
One test you can do is disconnect the fuel pipe to rail and see if she will start remember to crimp it off first yeah LOL fuel pissing everywhere is not nice  See if she will run with whats being burnt up?
I've heard some numpty have connected the wrong fuel pipes and mistook return and main feeds its a shot in the dark though mate! 

By the way if your over fueling is that bad the whole sump is probably mixed with oil this can cause issues so remember to change that oil!

[Craigwilson]

think I've done all of those, I ended up changing my ISV because the revs where taking so long to drop and were a lot quicker with the spare one, would this be related. and with the fuel hoses I don't quite see that plausible because the car was running perfect so unless they swapped round on there own,...... it's black feed blue return unless I'm mistaken?

[Craigwilson]

what is the blue/white wire on the air flow meter for, I've found it goes to the ecu but I pulled it accidentally and it broke from the plug very easily

[clipperjay]

Here you go this might help you the blue white is defo airflow meter signal wire could have found your problem!
Looking at the loom pins top row no. 1 Lower bottom row last pin no. 25
1 Start (50) red/green
2 OXS purple
3 Fuel pump relay red/green or yellow/blue
4 Knock sensor white
5 CO Adjustment blue
6 Ground (Sensors)
throttle switches
OXS
Hall sensor
Coolant temp.
CO pot/Air temp. --- brown/white

7 Knock sensor brown or yellow in shielded black cable
8 Hall sensor red/black
9 Air temp sensor blue/white
10 Coolant temp sensor brown/green
11 Idle Switch red/blue
12 Injectors red
13* Ground ECU brown
14 Power main / Idle stab. valve black/white
15 Full Throttle Switch blue/black
16 not used
17 Not used
18 Hall sensor green/white
19 Ground brown
20 MIL yellow - Yes This is the wire that stores fault codes off your Eprom! Max two fault codes before limp mode kicks in!
21 Not used
22 Idle stab. valve black/yellow
23 Not used
24 Not used
25 Ignition coil green

[Craigwilson]

cheers ! that might be very useful now and in future. could you clear up wire 20? does it have fault codes and a limp mode? also I repaired my wires to my airbox and it's not mosfireing but running terrible but I do have the maf off of the other 8v on it so it may just be setup different because that one has 130k and mines is cammed

[clipperjay]

Some cars had a VAG port as we called them, but they were on runout models and G60's esp American export models.
some were located near the handbrake lever, but don't take that as gospel they can be anywhere. Its highly unlikely you would have one, but you could always see if you can trace that yellow wire and see where it goes 
All digi's had default values if it senses two faults on sensors it would generically put higher values to ECU so you could get home on limp mode so to speak. If there was more than three down its limitations it cannot provide three default signals to help the car run better? My guess is that you still have a bit of work to get that running right, but guessing you might have more work to do yet fella and go through it again!