Yup, I cant help any more if the OP is determined to go down this path, I understand where he is coming from and was like that myself with the first electronic problem on my MK1 Octavia, now as a VCDS owner I know better, had I bought it then the vehicle would not have been scrapped and I would not have wasted hours of my time going down false tracks.

 

When I use a non recognised key like the one I keep hidden as an emergency spare (will get a thief in the car but not start it) it starts and runs for about 1 second but does not show up an immobiliser light on the dashboard, indeed is there even an immobiliser light on mine or more importantly the OP's dashboard?

 

VCDS or the equivalent will reveal all and will be cheaper than the parts cannon in either the short or medium turn, it will pay for itself many times over.

1 hour ago, Breezy_Pete said:

Fuse allocations and values vary with options and engine types, as do relays.

Your car does not appear to have the 'open driver's door, fuel pump spins up' feature.

 

Sorry to drip feed, but I'm tired and the engine-specific wiring alone for your car runs to 15 pages, and you have to dodge back and forth between pages to trace some connections.

CHFA engine, car built 02/08/2010. 👍

ok appreciated and no worries, thanks for the info. btw, fuse #16 is listed online as power steering, same 5A rating  so I'm wondering are the others I've listed above correct. ?  it's all a bit of a minefield isn't it !

JR and sepulchrave, I did say I hadnt ruled out an immo problem and said I would get VCDS on it (hoping VCDS lite will be good enough in first instance, Ross-Tech website suggests it should do some immo functions) and I also said I wasnt sure even if there was an immobiliser light on the dash., so I concur !

10 minutes ago, abba said:

ok appreciated and no worries, thanks for the info. btw, fuse #16 is listed online as power steering, same 5A rating  so I'm wondering are the others I've listed above correct. ?  it's all a bit of a minefield isn't it !

Fuses are often shared by multiple circuits, especially when supplying low current items like relay coils.

Please check the ones I've mentioned, it all helps to narrow down why things may not be working.

 

Fuse 3, 10 Amps rated is necessary for the ECU relay to do its thang. Another one to check.

 

@sepulchravea lightning strike isn't required to cause electrical faults in Skodas, a simple broken or shorted wire is just as capable, and overwhelmingly more likely. Mk1 or Mk2 Fabias with no wiring issues at all are probably extremely rare beasts.

Edited 17 September, 20232 yr by Breezy_Pete

 

Can't remember if you've said you hear fuel pump run at ignition on?

 

If not, see if you can get it to run by shorting terminals 2(30) and 8(87) of the fuel pump relay socket.

ok thanks will check all those fuses, this website seems to broadly agree with the numbers youre coming up with, though the relay info doesnt match. relay numbers are embossed into the plastic ? 

https://fuseandrelay.com/skoda/fabia-2.html

Yes was planning to make up a link to short the relay contacts, and no, Ive not yet heard the pump run. and we're not getting volts to it (as above, assume they're the thick wires of the 5 that go into the pump, colours brown (pin 5 earth ?) and blue/white (pin 1) see photo. thanks chap. 

Relay position numbers are all I've been referring to. The numbers on the ends of the relays aren't mentioned in the circuits. Sockets should be marked with numbering.

What positions are there relays present on your car?

Yes, thick wires to fuel pump are power (blue/white) from relay and ground (brown/violet). Others are for the level gauge.

many thanks for all your help, will check tomorrow and come back to you. 👍

12 hours ago, Breezy_Pete said:

@sepulchravea lightning strike isn't required to cause electrical faults in Skodas, a simple broken or shorted wire is just as capable, and overwhelmingly more likely. Mk1 or Mk2 Fabias with no wiring issues at all are probably extremely rare beasts.

 

He was referring to ECU failure Pete.

 

The one on my burnt out Galaxy looked like it had been deep fat fried then put on a bonfire for a few hours, under the soot were all the tempering colours of heat treated steel, there was a mass of bare copper strands going into a molten blob of plastic where it had been cut from the loom.

 

By carefull cutting and prising I manged to seperate the melted blow and wires from the inner connector, I did all this in the hope that I could dress it up enough to PX it against a (not) refurbished one, nobody would accept it considering it to be completely destroyed inside, I opened it and the PCB was charred and discoloured by the heat and decided I had nothing to lose by trying it.

 

Once the new loom was fitted I plugged it in and the engine fired up straight away, granted I had no end of other problems to resolve, it wouldnt idle (bypass valve siezed) and there was weeks of faultfinding to get all the other circuitry functioning but the ECU survived intact and was still working well 2 years and 60K miles later.

 

They are pretty bullet proof and probably would even survive a lightning strike on the vehicle, we used to build that protection into military vehicles a 15 years before at considerable cost but the technology becomes very cheap quickly and adopted in the mass market, an EMP pulse would take out an ECU but there would be no humans left around to complain about it!

37 minutes ago, J.R. said:

 

He was referring to ECU failure Pete.

 

 

Exactly, I've never seen or heard of a genuine ECU failure, it's a euphemism in the motor trade for " we don't know what's wrong with it, but if you'll pay this ridiculous bill we'll pay a guy we know who can fix it and we'll keep the change".

Fair enough, I just had the impression you two had decided it's definitely an immo problem, and were dismissing any other investigation as pointless.

 

Thing, is, with immo trouble, the car usually starts then cuts out, with an amber warning light (key). This isn't what the OP is telling us, it's a crank-no-start situation (without easy-start), as I've read it?

The warning light is shown as being just below the resting (0) position of the speedo needle, side view of car with key.

 

 

Edited 18 September, 20232 yr by Breezy_Pete

Yes Pete, that is how I read it as well, but as he said it was not running before the new ECU I speculated that there was and is a fuelling problem that is now compounded by an immobiliser problem.

 

I just tried mine with the non RFID key, started and ran for a couple of seconds then stopped with flashing glowplug light amongst others, 2nd and subsequent attempts had the flashing glowplug light and no start up, Maxidot displayed "Key not found"

 

 

quick update on this, been a long day stuck upside under a dashboard. (relay plate is horribly inaccessible). vehicle now runs though. fuel pump relay checked out ok  when removed and tested (relays usually pretty reliable  and this is just the most basic four terminal (SPST) jobby). fuel pump and car ran ok when pump hard wired to battery via a manual switch. concluded that there must be a break somewhere in the wire from the relay output to the pump, spliced in a new section of wire to bypass the split and all good. switched output from FP relay (position 7 in dash) is a thick blue wire, now connected by new wire section to the Fuel pump feed which is thinner blue/ white stripe cable - would like to confirm by checking wiring diag that this is ok (well it works). 

Fuse 30 was literally the missing link, apparently.