abf no spark, HELP!

[rubjonny]

no its earthed via brown wire, and the spark leads. check the gearbox earth is ok, it runs to a stud on the end of the rear engine-> box mount.

hasve you plugged it into vag-com yet, also check the measuring blocks. does fuel pump prime with ignition then continue to run as its cranking over. try a known good coil as well.  are you sure the leads are good, mate of mine had new beru leads but a couple of em broke within a month or so

[valver3g]

oh,  well i bought a fault code reader that claims to do exactly what vag com can do and it did have two codes, one immobiliser preventing engine start and air temp sensor + or something similar and i cleared them but they have came back. measuring blocks? sorry i dont know what they are? yeah fuel pump primes i can hear it and checked on the injector rail to see if there continues to be pressure by taking out the black plug type thing well this one is literally brand new from a place i trust. as for the leads ive tried a set i got off a ibiza at the scrappy AND the original set that were perfect before all this sh!t happened still no spark.ill check the gearbox earth, does that earth the starter?

[rubjonny]

i think you now have 2 issues, first it seems you are loosing power to the starter, probably due to the battery being knackered. 2nd you are now seeing engine start blocked by the immobiliser. read the immobiliser fault codes, this will tell you why the immob is kicking in.

the measuring blocks are an advanced feature of VAG-COM, which some cheaper code readers wont have. VAG-COM is the software you install on a laptop to use with the usb/serial vag-com cables. what you can do with this is check the sensor inputs to the ecu, like ecu temp, inlet temp, throttle position etc.

[valver3g]

sory that was a typing error , i meant the codes have NOT came back. the reader cost me 90 quid and yeah u can check and adjust the measuring values of each sensor, but i havent tried it yet.

[valver3g]

Right, spent two days checking everything over the other day and traced the sparking problem to the ECU, seems the + and - on the coil have shorted and popped a diode in the ecu!? so got a 24p 4002 diode from maplins and soldered it in, spark sorted. however it still didnt want to start it wants to, spluters, then runs slowly on what sounds like 1 cylinder. so checked the timimg AGAIN, spot on, so removed the injector rail and turned the engine over, all sensors are plugged in and its only injecting on cylinders 1 and 3  wierd, is this normal before ignition or is there something else wrong?! cAN ANYONE HELP!? could it be a dodgy oxy sensor?
cheers

[rubjonny]

sounds to me like more has gone on the ecu than just that diode. buy a new one mate, just make sure its the right one to match your car, i.e. pre or post 96. early ones dont ahve the immobilser, late ones do. though you can run non-immob ecu on late car, cant do it other way round without adding in all the immob stuff. if you have vag-com you can match another immob ecu to your car easily

[valver3g]

do you by any chance have a wiring diagram for the digifant 3.2 ecu? just il try and fix this one if i can coz il have to fanny on with a new immobiliser and set of keys and could end up being a tad more expensive than a few ecu components.
cheers

[rubjonny]

sure do:
http://vwtech.no-ip.info/downloads/g3abfecu.pdf

you dont need to touch keys or immob when swapping an ecu, just use vag-com to code the immob box to the new ecu. takes all of 5 seconds

edit: like this, but as it says near the bottom need to select 'immobiliser' not 'instruments'
http://www.ross-tech.com/vag-com/cars/immobilizer2.html

[valver3g]

cheers
im gona have another look at it this weekend n replace the ecu relay and fuel pump relay just incase.