MarsRed Cab 16v Conversion * NOW STARTED*

if you can access immob box then the vagcom port and wiring is all ok, the immob box is powered up ok as well so that at least is fine. seems problem is the wire from the immob to the ecu, or the immob box has packed in where it is unable to switch over to ecu diagnosis (thats what the clicky noise is)

replaced fuel pump relay with no18 and we put a new fuel pump on today and still the same.
 
we also tried it with the immob box disconnected. no luck

i held the immob box when turning on ignition and i couldnt feel or hear any clicking.

what does this mean??

i guess it gets a live feed from the ignition, need to test with a multimeter if its gettin power to it when ignition is on and cranking an stuff, and if its got a ground....

ok cool so we know issue isnt fuel wiring related, so you can put the proepr pump relay back in. if you can scan the immob box it is switchign on fine,. id suspect its broken internally. try another one from scrappy just to see if you can scan ecu thru it, if you can then you'll have to get another matched immob box and chip

This is driving me mad.

I think ill systematically check all the wiring from loom to fusebox as there was some I was unsure of.

Im pretty sure there is a yellow wire from obd port which is not connected to anything.

I'll confirm exactley how the obd and Immob box is wired to fusebox as well.

yellow wire isnt required, as i say if you can talk to the immobiliser box the vag-com port and immobiliser are wired up correctly. however the wire from immob box to ecu may be at fault, or the immob box itself. the fact there is no clicking going on suggests its faulty asd it should click with the ignition and also while you try to scan the ecu

it might possibly be the wire from immob box to ecu and the wire to vag-com are the wrong way round, but if the original plugs are still on there then you cant really mix them up.

anyway check my sig for the diagram for the immob box, g3immobiliser.pdf

Had a bit of a check of the electrics today rubjonny.

Confirmed I have 12v at fuel pump.

Also have 12v at coil if I connect + to coil and earth off battery.

I have also realized that whether I have no. 18 or 167 relay and with either fuel pump fitted as I now have 2. And whether or not I have throttle or not the car will start and then cut out after exactly the same time.

I rechecked the immob box today. It does click and it also clicks when Im scanning it.

I had a look at your wiring diagram and I think it may be wired up wrong. I mapped out the wiring today and it is as follows.

OBD
RED/WHITE-FUSEBOX-PERMANENT LIVE

BROWN- EARTH CLAW

GREY/WHITE-CONNECTS TO GREY WIRE FROM IMMOB BOX

IMMOB BOX
GREY- CONNECTED TO GREY/WHITE FROM OBD

GREY/WHITE-CONNECTS INTO ENGINE LOOM VIA A BROWN MK3 CLIP PLUG

BLACK- FUSEBOX IGNITION ONLY LIVE

2X BROWN-EARTH CLAW

If you see my previous posts there is a pic of the code im still getting. Im reading the same code on a Vgate scan

I get 1 code from immob box which says
DATA WIRING FAULTY
STATIC-IMPLAUSIBLE SIGNAL

HELP ME :dontknow:  :dontknow:  :dontknow:  8O

ONE THING TO ADD IS THERE,S A BROWN/WHITE WITH A FEMALE SPADE WHICH COMES FROM LOOM.

wiring all seems fine to me if its as per your list. the grey/white with female spade is an earth for the mk1 gti cluster (with mfa) so if its not got one of those dont worry.

im leaning towards a faulty immobiliser unit, as i say you cn use any random one nicked out the scrappy just for testing. If when plugged in you can then communicate to the ecu then you know you need to get yourself a matched immobiliser box and chip

if you can find a mk3 in the scrappy with the matched chip then even better

I've just got my feet back on the ground.
Got a new Immob box, halo and chip.
Fitted it today and the car behaves no different.

I'm getting the same fault code as well.

00546
Which is
Data cable faulty or ineffective

How do I fix this

sounds like the problem is your ecu connection, the grey/white wire from ecu to behind the fusebox may be damaged somewhere or not connected to the right place. it runs from ecu pin 43, if you cant see anythign up then it might be an idea to remove the loom, unwrap it then trace the wire from pin 43 all the way back to the fusebox area

what a bummer.

if i take it off tomorrow, how do i confirm/deny it's faulty apart from identifying a physical breakage.

would this explain the starting and cutting out?

or only why comms are not connecting to engine?

Right, this is the latest.

Took the loom out the car earlier.

Used a multimeter to do a continuity test as soon as I took it off.

And it showed no continuity.

Brought it home and unwrapped the whole loom. Now its showing continuity every time I try it.
00.7 ohms resistance.

Would I be right I thinking it must have a small breakage inside which must have not been connecting whilst taped up in a particular position.

Should I replace the whole wire.
If so how do I go about doing the ecu connector and the Brown pin for Immob.
I was think leave an inch at start and finish and replace the whole middle if you know where I'm coming from.
Would that be okay.

check the pin is secure in the socet, and isnt all bent or wobbly. trace the wire all the way from the ecu to fusebox very carefully, look for any damage to the insulation or any parts that look knobbly or kinked, which might point to internal damage even if the insulation looks ok. make sure you remove the back of the ecu plug so you can check inside there as well! grab the diagnostics wire at the back and gently tug to ensure its firmly seated in place and wont pull out when you try to connect it back to the ecu.

these are the harder faults to trace! as you say you could cut a couple inches off each end and solder in a new section if you like

nice build thread matey, ive got a 9A to drop into my caddy next.   this is giving me ideas about dressing the engine nicely rather than banging it in!

Hope you get the wiring issue sorted (massively frustrating) i had a fueling issue with mine when i dropped the mk1 gti in place of the 1.6d did loads of test to determine the problem and it ended up a actual bolt in the fuel filter rather than bolt with all the perforated holes !!