G'day all, I have a 4L EF Futura wagon with an Impco gas setup (petrol not working for some reason, no power to petrol pump....will investigate when able.....so has to start on gas and sometimes backfires). The smartlock module has been playing up for a while and I've just been giving the dash/console the usual thump to start up about 50-60% of starts. But the main problem today is it backfired, heard a clunk from engine, tried keying it again then starter motor whirred but didn't seem to engage, tried again but now there's no action at all from starter. Found the battery was weak so fitted a better one from my V6 Pathfinder....lights etc.work but still the starter won't give a kick (can't even hear the starter solenoid click). All fuses in the dashboard panel seem good. Checked the big ?fuses under the bonnet - all seem OK except can't get the MAIN 100amp out of it's seating (seems to be jammed/fused onto the pins.....This shouldn't be the case should it ? is there a secret to getting it out ? is it possible that this is fried ?? ) . So many variables but can anyone comment on possible next step to try ? (car is now stuck in the carpark at work so tomorrow will try removing and replacing that main 100amp fuse....need to find another one just in case the old one breaks trying to get it out!!). Or could it be that the smartlock module has finally given up the ghost for good?? Thanks in advance for any input....Steve.

i think u have a few areas to look at,

replace the bcm(smartlock), common problem of dry soldered joints inside it
starter prob, maybe a loose wire on starter or starter about to go, maybe loose bolts??
main fuse, could have dirty joint and is arcing out, so try another there. some crc may help, pretty sure repco/autobarn/bursons keep them
fuel pump not working could be bcm or pump relay (found under coolant resevoir, green one) or dead pump if the tanks is left empty sometimes

Thanks XR, so that main fuse should be just as easy to pull/remove from it's socket as the others yeah? and if that's knackered could that stop the starter circuit from engaging? also....just in case it's just a matter of not strong enough current (even from the newer battery) to engage the starter solenoid....I might also try jump-starting it with the other car. Another question : with the backfiring sometimes on startup, the backpressure used to blow the air-box lid/clamps off and even terminally distorted the paper-filter, then I fitted a pod-filter piped inside the airbox (to keep it legal)....but as it's all clamped the backfiring sometimes blows the large hose off the throttle-body (?weakest link) - so can this sort of backpressure damage the engine or maf or gas-mixer etc ? sometimes after a backfire the engine runs roughly and there's a clanking/shuddering noise, turn engine off, restart engine straight away without backfiring and it purrs as usual...if it doesn't start smoothly the second time it's usually because the hose ducting to the throttle-body has blown off (reconnect and starts/runs fine). Probably better to return to the standard panel filter setup so vents off that backpressure when it hits.