ECU dodgy help!

[valver3g]

its a golf gti mk3 16v, abf engine, digifant 3.2 ecu. ive read that the spark advance is controlled electronically, could this be the problem?
im testing spark by taking the plug out and earthing it to the head.

[javalin]

>ive read that the spark advance is controlled electronically, could this be the problem?
Yes it is, but no, its not going to be the problem as such.  As long as the ignition timing is set correctly then the ECU can alter the spark timing within the width of the rotor arm (I assume you've got the correct arm fitted?) - the arm has a wide band of contact rather than a point if you see what I mean?

Have you tried a working plug in a non-working lead, and a working lead and plug on a working terminal?  We're missing something if the spark is getting to the dizzy but not all four plugs.  Have you tried a proper dizzy cap - perhaps the clear ones are slightly off size?

James

[rubjonny]

there is no ign timing adjustment on the abf dizzy, its locked in place. so all you need to worry about is lining up the cam and crank to TDC

[Sirminty]

Just been reading the thread and am a little confused
Am i right in reading that he is getting a spark on all four points on the dizzy but not at the plugs!!
if testing using the head as a ground and not getting a spark? it narrows it down to lead/connections or plug? 
I could be completely wrong and sorry if so
 :embarassed:

[javalin]

>Just been reading the thread and am a little confused 
me too.

Yes you seem to have same understanding of the problem I have - however he does appear to get spark on 1 & 3 by grounding to the head - so in theory the same test with 2 & 4 should work if the plugs & wires are good.

>it narrows it down to lead/connections or plug?
yes - however he says he has tested that.  Pondering on timing and/or incorrect parts in the dizzy now.

James

[valver3g]

i know that all spark plugs are good, there a triple contact plug and they work spot on in my mates mg, so like you say il check the leads again. il be doing this all on saturday as i havent had the chance to take another bash at it. the dizzy is ok, ive tried unplugging it and im getting the same problem. the rotor arm is brand new bosh part, and ive got a brand new abf dizzy cap, i just used the clear cap to elimenate the rotor arm and dizzy cap. if its not the leads then could it be that the signal from the ecu to the distributor is some how 'stealing' the spark when the rotor passes contact for some reason or is that impossible? just a thought considering the ecu has been cooked previously, before i replaced the diode.
and all this still doesnt explain how the matching injectors arent working? im a bit stumped. il try to split the rail and test each one individualy, just incase its a coinsidence.

im going to test the knock sensors, air temp sensor and lambda sensor.
when it first packed in due to overfueling, the cat was glowing red when i looked under the car, could this have damaged the oxy probe?

[javalin]

>could it be that the signal from the ecu to the distributor is some how 'stealing' the spark when the rotor passes
no.  if it was grounding the spark to the ECU then - dead ECU.  Crank sensor should initiate the spark so I don't think the cam sensor should be too involved.  You could try with it unplugged - may have an effect on the injector problem I wonder - as cam sensor is used to control injection batch vs sequential injection I believe....

>im going to test the knock sensors, air temp sensor and lambda sensor.
ok - but doesn't effect this problem on starting.  Try with the lamda, MAF, knock and air temp sensors unplugged.

>il try to split the rail and test each one individualy, just incase its a coinsidence.
yeah - if its multi-point injection - i.e. a rail and 4 injectors - they must come off and be testable/replaceable.  Perhaps they got damaged when you damaged the ECU last time?

James

[Wayne]

The more I read the more I think you have a ecu problem 

[javalin]

The more I read the more I think you have a ecu problem 

Quite likely that will be the solution, but why isn't the getting a spark for all plugs past the dizzy?  Thats got to be dizzy, lead or plug related. 

James

[Khare]

The more I read the more I think you have a ecu problem 

Quite likely that will be the solution, but why isn't the getting a spark for all plugs past the dizzy?  Thats got to be dizzy, lead or plug related. 

James

Yeah but the fact that injectors 1 and 3 have no life then it sounds like an electronic problem rather than an issue with the distributor/leads/plugs.