Can anybody let me know if an aftermarket computer (Autronic in my car) can loose its tune or settings after a period of time without the battery connected. I have had my car off the road for approx 12 months without battery and am having trouble getting the car to run it keeps backfiring and missing. I have changed plugs, swaped leads, changed distributer, checked injectors but still cannot get to run.

Its possible sure, depends on whether any battery backed non volatile memory is used or if eeprom is used it glitched during a power up/down. Most likely is that leaving a system unpowered over 12 months results in minor corrosion of connectors, suggest unplug and plugin all connectors a dozen times or so just to "exercise" them, edit: Any analog sensors like AFM, MAP, CTS are first things to check as ECU really really needs a stable and clean signal there to base all its maps on...

Thanks niche for the fast reply. My ECU is Autronic SMC I really dont know much about them on weather they have back up built in. I have had the engine running but not to well and whilst running checked sensors by unplugging and reconnecting the only one that stalled the car was the vacume line that runs back to ECU from plenum and possibly CAS but didnt try that one, but TPS, sensor in intercooler piping and O2 sensor didnt make noticable change. I did give the terminals a good clean aswell. All injectors seem to be working and there is spark but car miss fires and backfires sort of flutters as you try to bring the revs u into it.

hey had same problem pulled each injector harness off and ended up being a clogged injector with a dodgy harness as well, Or double check all leads plugs, and make sure on right numbers.

Backfire tends to mean ignition related as its not getting burned in chamber and reaches exhaust with some air that also hasnt been consumed, if it was just running rich there wouldnt be air in exhaust to combust, so I would focus in that case on coil, power transistor, leads etc... DONT unplug/plug in while engine running, can cause all sorts of issues... edit: You only do that if you really really have to as part of a specific diagnostic procedure and know what you are pinning down and kwow what to look out for if you stuff the ECU input stage from inductive feedback Some original photos have not been recovered yet.

I think its highy unlikely that its 'lost its tune'...highly unlikely. Never heard of it with anyone i know who has an aftermarket ECU and Autronic are up there with the best... What did you do to the car while it was off the road? May help with suggestions if you provide some background around why it was running for 12 months..

ive heard of someone on here frying their autronic after their bat went dead, i think it was nomad but not sure.

thanks for the reply guys it seems to have cleared itself up. It must have been the older fuel in the tank that was making it run badly. I did put new fuel in the car befor running it but there must have been some crap still in there and it has now flushed threw. Now some last bits and peices and I will take it for a drive for the first time in a bit over a year must admit looking forward to it.

Quote: Originally Posted by tdoyle88 ive heard of someone on here frying their autronic after their bat went dead, i think it was nomad but not sure. Wasn't that because he tried jump starting it positive to positive?

Quote: Originally Posted by Yeti Wasn't that because he tried jump starting it positive to positive? you mean positive to negative.

Lol, that'll **** anything!

Heh i once connected my battery leads around the wrong way.. just wasnt concentrating. Notice to everyone: DONT DO IT!! Scared the crap out of me with the smoke and electicity noises! Some original photos have not been recovered yet.

i did that to my boss' car at my work a few months back by "accident" his an ass, only thing that stoped working was his radio but Some original photos have not been recovered yet.

Yeah man its not good. As soon as i did it all the little plastic connectors comming of my battery started to melt and smoke like crazy, i instantly ripped off the neg wire and luckily everything still works! lol

Quote: Originally Posted by Yeti Wasn't that because he tried jump starting it positive to positive? And you've been told your information by who? And the answer is no.... I've had 2 microtech's in my car.... Both have been fried... RACV did it the first time and yes I did it the second... But it wasn't "+" to "+" I'm not that flucken stupid...

Quote: nomad the second... But it wasn't "+" to "+" I'm not that flucken stupid... well said .. and 2nd .. i am getting a ecu very soon, does that mean neva jump start the car........ ????????????????

No you can jump start any car.... Jump started teh VNSS the other day... Its running a chipped ecu & micro lt10.... A tip to remember.... Turn headlights on... So if there is a surge of power it'll blow the headlight globes and nothing else

Quote: nomad A tip to remember.... Turn headlights on... So if there is a surge of power it'll blow the headlight globes and nothing else so the lights help from friing the ecu ... so in this case you forgot to turn your lights on.... right so what happends if your lights dont even turn on .. then if this happend and i just changed the batarys over and started the car, then will that burn the ecu ... ?

if there is an electrical surge (too many amps put into the system) the headlights will take the surge and blow instead of blowing ur ecu (your headlights draw more current than ur ecu). cheers for clearin that up paul

Quote: Originally Posted by nomad And you've been told your information by who? And the answer is no.... I read it in members, must have been someone taking the piss