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Model specific boards => Golf mk3 => Topic started by: valver3g on 14 February 2011, 16:59
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does anybody have experience with ecu's? mines a digifant 3.2 from an abf. iv only got a spark on cylinders 1 and 3 and only injectors 1 and 3 have life, i think the problem is wherever the system splits in the ecu but i dont have the foggiest apart from that, any help would be much appreciated.
cheers
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Get it scanned for fault codes as a first step.
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sounds like possible crank sensor fault to me?
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ive replaced it not so long ago. are the two knock sensors on the block linked to injection and spark timing in any significant way? just it runs, but on what sounds like one cylinder then after a while just dies.
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>are the two knock sensors on the block linked to injection and spark timing in any significant way?
yeah the knock sensor is used to retard (spark closer to TDC) the inition timing to prevent engine damage. Don't think it directly effects injection timing. Spark retard would effect all cylinders.
surely if this is a mk3 with a single ignition coil, then if the coil is sparking for one cylinder it will spark for them all? dizzy fault?
As for injectors, could be unrelated, bad wiring etc? (could also be transistors in the ECU not able to switch completely to ground). Either way I'd check the wiring first before condeming the ECU.
James
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javalin
yeah i thought it was strange that only 1 and 3 were sparking il triple check though. yeah its and abf coil is new, dizzy is good, rotor is brand new bosch dizzy is brand new. i bought a clear cap so i could see exactily what was going on. there is spark at all 4 terminals and leads are good however no spark at plugs 2 and 4? ?? ive checked the whole loom for splits and bare wires, all good, ecu has seen better days it got damaged, my mate shorted the coil i think and a diode went pop in the ecu, replaced it and theres no other signs of damage, do you think im better of getting another ecu?
before it packed in it was heavily over-fueling, down to the crank sensor but i replaced it. can this damage knock sensors?
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>can this damage knock sensors?
no
If you have spark at the dizzy either your leads or your sparkplugs are broken (are they gapped correctly?). Fixing one or either of these would seem to solve your missing spark issue. (possibly also you *could* suspect a coil fault here to - if the output voltage was low it might not manage to spark the plugs)
>my mate shorted the coil i think and a diode went pop in the ecu
doesn't sound great.
Out of interest - if you connect a working injector plug i.e. 1 and connect to injector 2 does it squirt fuel? How are you checking? Does no.4 work if you put number 3 lead on it? I know it won't run in this configuration but trying to isolate faults.
Let us know how you get on...
James
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Spark plugs are all ok, ive transfered them to my mates mg zr and they all work with a strong spark. the leads are known good, and ive tried with my mates leads. same problem.
the coil is brand new and i got it from a reliable dealer, i know the guy well, and in any case 1 and 3 are getting a strong spark, so i would have thought 2 and 4 should?
the injector rail is a sealed unit with only one connection to the wiring loom, not individual plugs. i tested by removing the rail from the inlet manifold, connecting everything back up, and checking visually which ones were 'squirting' while my mate turned it over. i considered that the rail is faulty but it seems too much of a coinsidence that its both injectors and spark on 2 and 4 that arent working. any more ideas?
cheers
Ross
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I would try another coil pack, I know it is brand new but you can never be sure.
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what car is it? What engine?
>and in any case 1 and 3 are getting a strong spark, so i would have thought 2 and 4 should?
if via a dizzy then yes. Something isn't adding up - you can't have spark on 1 & 3 and not 2 & 4 if the leads and plugs are working on all 4. How are you testing for spark?
James
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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.
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>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
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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
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Just been reading the thread and am a little confused :huh: :huh:
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? :sad:
I could be completely wrong and sorry if so
:embarassed:
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>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
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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?
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>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
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The more I read the more I think you have a ecu problem :undecided:
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The more I read the more I think you have a ecu problem :undecided:
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
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The more I read the more I think you have a ecu problem :undecided:
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.
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Change the ecu relay! :grin:
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>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.
but seperate problems surely? Ign coil is firing so he should get 4 x Sparks, but if the injectors aren't running either: (1) broken injectors, (2) bad wiring or (3) transistor drivers faulty on ECU
James
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The more I read the more I think you have a ecu problem :undecided:
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
I think they are 2 faults as such, injector problem cannot really be much more than the ecu as that is all that really controls them.
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or bad wiring, or bad injectors or bad sensor(s) (crank/cam). Makes sense to prove these before condemming the ECU I'd of thought.
At the end of the day - it just does what it knows howto based on its inputs.
James
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Khare> how much do you want for the ecu? whats the code?
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ECU is 037 906 024 AB :smiley:
You have PM on the way :smiley:
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Javalin/james> well ive changed the crank sensor already, and if it was the crank sensor surely it wouldnt get a spark at all? or does it use seperate notches on the crankshaft/ flywheel to tell what the position of the piston is in each cylinder? ive tried with the dizzy unplugged but i only checked the spark not the injectors,il do that on saturday. it has no mass air flow sensor, only air temperature and intake manifold pressure sensor, but il try unplugging them.
is there a micro relay for each injector within the injector rail or is that all in the ecu? yeah its multipoint.
il try checking 2 and 4 leads again
il try what youve suggested sensor wise, if all fails i think its going to have to be a different ecu.
does anyone know how to recode an ecu with vcds/vagcom?
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Khare, AB is the un-immobilised ecu isnt it? yeah the price u sent sounds ok. il let u know buy the begining of next week as im going to have one last try at it on saturday.
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I THINK it hasn't got immob. Reason I say it is because it's pre 95 ECU, AE and BE were used after that. Someone will confirm though :smiley:
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thats non-immob ecu aye, superceeded by 037 906 024 G then 037 997 024 GX
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Did all gti16vs have abs? is there anything the BE supports that the AB or AE doesnt? like trip computer or owt like that? mines a BE its on a P plate.
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Abs was standard on all mk3 GTI's I believe.
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can use any ecu on any age mk3, abs computer doesnt talk to it in any way so no bother there. its not like later cars where abs needs to be coded to ecu :)
only thing thats slightly tricky is the immobiliser, if you swap another immob ecu over you need to use vag-com to code it to the immob box. but if you get a non-immob ecu then the immob unit is ignored anyway :)
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ok, so if i get an un-immob ecu AB does that make my car more 'stealable'?
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indeed, if it doesn't have an alarm
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bollocks, well i had a cobra alarm fitted but i ripped it out incase it was messing with the ecu in some way, turn out it wasnt, but ive still got it. itl be going back on then! :laugh:
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well if it was me i would get an immob ecu later once you confirmed it is the ecu, then you can code it in with vag com. just be aware you'll have to cut the square locking tabs on the corners of the ecu to get it to fit your ecu plug. you'll see what i mean, no big deal or anything :)
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well ive got a choice of buying an AB for 50, or a BE to match mine for 65. ive spent all yestaerday, checking the injectors, theyre fine, leads and plugs, and double checking timing and lead layout on the distributor. all fine
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well replaced ecu and matching immobiliser and key chip. still no luck. ive now replaced ecu, coil, distributor, leads, plugs dizzy cap, rotor, crank position sensor. only getting spark on one plug. could it be a dud crank sensor?
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well replaced ecu and matching immobiliser and key chip. still no luck. ive now replaced ecu, coil, distributor, leads, plugs dizzy cap, rotor, crank position sensor. only getting spark on one plug. could it be a dud crank sensor?
Worth trying one :afro: