ECU dodgy help!

[valver3g]

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

[Wayne]

Get it scanned for fault codes as a first step.

[rubjonny]

sounds like possible crank sensor fault to me?

[valver3g]

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.

[javalin]

>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

[valver3g]

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?

[javalin]

>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

[valver3g]

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

[Wayne]

I would try another coil pack, I know it is brand new but you can never be sure.

[javalin]

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