ECU Trouble!!!

[Mick]

Hey guys,

started to get an occasional pop at idle a month or so ago and all of a sudden its dropped cyl. 1 and idles on 3.

VERY intermittantly it idles on 4 again for maybe a second or two.

assuming a blocked injector i had them cleaned today and they're all fine.

being a vr4 motor i took off the ignition pack (joy) and everything was ok if a bit dirty and i'm getting a good spark in no.1.

taking off the injector connection to no.1 does absolutely nothing and speaking to a local workshop they reckon the computer may be dying.

the computer is no shit a "remanufactured mitsubishi ECU". flash tuned something i guess.

the guy who did the conversion got sick of spending $$$ and chucked this shit heap in instead of getting a motec like he should've!

any ideas guys? first of all the problem or if so choice of computer for vr4?

:beer

[Starion VR4]

Ok, is this a VR4 engine with 2 coils wasted spark unit?(2 leads comming out 1 coil) If so it's not yr ecu, as it outputs to a Ignitor unit which fires each coil alternatly, so if U have good spark on 2,3,4 then yr ok, check the spark on all plugs with sparkplugs in them restiing on head, disconnect the injecters so it doesn't fuel engine, if spark ok, look else where, check yr compression, should be 130Lb. Go from there. let me know :beer

[redzone]

u need 2 buy a noid light from ur local car parts joint and plug it into the offending injector plug on the harness. if it flashes, u have pulse. then plug it back onto the injector and listen to the injector while the engine`s running with a long screwdriver held 2 ur ear to hear the injector solenoid ticking. if both ok, u have either a dead plug or an actual engine problem.. :beer

[flav]

You can just unplug the injector when its running, if theres a difference then thats not an issue. I would replace that plug to begin with, then the lead if theres still a prob. but sometimes its just something else altogether that sounds like a miss. Check your plug tips when its just happened by shutting it off and see the difference, you can tell by reading the plug colours to what its doing. A wet plug is not a fuel issue.

[JD_Stazza_Brendan]

Also if the timing is very retarded it sounds like it misses.

[Mick]

thankyou dudes a heap for your input i told all this to a very reliable local efi specialist (howell automotive) and after the injector pulse was confirmed and therefore clearing ecu damage, apparently the coil pack is failing because although there was a spark which i tested for initially and found something, its not enough to fire the cylinder consistantly.

this makes sense with the problem having come along way off and stupid me thought i knew something.
after taking the pack off it has started to melt through the no.1 cyl lead port and though the resistance of each coil is consistant, it is in fairly shite state of repair.
so a new coil pack, (diamond something??) is on its way and should have all this sorted.

again thanks heaps guys will confirm this when the new one arrives :beer

[Mick]

happy to say its sorted and was the coil pack!

given the old girl a new lease of life, it pulls really well!!!

thanks for your help guys :beer

mick

[flav]

always happy to help! :D