General uno turbo misfire

[philly g]

Hi chaps, new to this forum:wave: got a problem with me 93 uno turbo standard boost. for quite a while its had a problem with a misfire it goes through spark plugs like no tomorrow. it will run on iridium only, any other type of plug it dont like it will misfire and backfire underload. iridium dnt last anymore then 2-3 months at most, starts off with the odd misfire on cold start then gets worse till a plug fails completely. ive changed coil, module leads cap+rotor, plugs(alot of them) injectors cleaned and leak testedmany other bits but forgot cos aint used the motor in 2 years. it does seem like spark blow out, so must have a weak spark. anyone had this problem. got me stumped????????????????

 

[the mk1 kid]

What do the plugs look like when you remove them after they die?

Tom

 

[SteveNZ]

Plugs dont wear out that fast, I assume they are just getting oiled up and not working etc.

Assuming it is actually the ignition (it could be over fueling or compression) you can check a few things. This is what I would do.

Check power and earth to coil. Voltage drop anywhere here is bad. Wiring to coil has been known to fail.

Check ign module itself (difficult). Signal from module to coil, voltage drop and trigger from microplex to module - try and get it to missfire, and see if the signal changes, you really need a scope.

Check sensor output - sensor air gap etc. Ive never seen a failed microplex, but its still possible.

Just use standard copper plugs to get it to go, cheap and adiquate.

 

[philly g]

mk1 kid, plug just wet with fuel. i have checked all those things like voltage to the coil etc i havnt gone 2 deep into it though
as never had the time back then but cause iam planning on taking engine out and doing a rebuild, just wondering if any one had suffered a similar problem,im just guna have to go through it again probley did miss checking something on the way.