Chicken Drumstick Posted February 26, 2021 Share Posted February 26, 2021 My Uncle & brother have had a 3.9 EFI from an RRC fitted to their factory 3.5 twin Stromberg 90. Fairly simple swap and just utilised the RRC EFI setup. But they are having issues with the battery going flat. I noticed the fitter has run a wire from the ECU to the 12v positive terminal and labelled ECU perm live. Is this needed? Could it be routed to an ignition live? I'm not sure what would require a permanent live and I wonder if it could be causing the flat battery issue (it isn't the battery itself or the alternator). And nothing else on the vehicle has changed and it never used to suffer this problem. It'll go flat in 5-7 days and be unable to start. Thanks. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 26, 2021 Share Posted February 26, 2021 If you remove it, the stored values for the stepper motor, and anything else that is designed to persist, will disappear. It will give you a poor initial idle control, and if you have lambda sensors, fuel trims will reset each time, as well as possibly some other things. The permanent live to the ECU is no different to a relay being hooked up to permanent live, and triggered by ignition live, so shouldn't be causing issues unless there is a fault in the ECU. Trace the fault with a meter in series with the battery,pull each fuse and see if there is a drain, and if it changes as you work your way through the fuse box, you have found the circuit. 2 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.