Kassan1973 Posted November 19, 2020 Report Share Posted November 19, 2020 During my testing of a crank sensor i came across another issue, when i have ignition car not running and turn head light on fuel pump would prime , after connecting PC to check whats happening it seems the fuel pump, tach output and isc output all activate for a second with isc indicating crank % dc each time i turn the headlights on with ignition on car not running , my ecu earths are directly to engine i havnt checked anything yet but i would assume the headlight wiring earth may be suspect as i have relocated battery and these earths that did go directly to battery are now earthed to the body instead do think this would be a fair assumption. G4 extreme ecu ford EB sedan Cheers Dean Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 20, 2020 Report Share Posted November 20, 2020 The fuel pump and ISC activate when the ecu sees the first "pulse" from the crank sensor. So it sounds like there is some headlamp current passing through the ECU wiring somehow, making the ecu see a small pulse on the trigger input. You could try using a jumper lead from the battery -ve post to the headlamp ground connection point to see if bypassing chassis solves it. if it does it would suggest chassis to battery is higher resistance than it should be. Quote Link to comment Share on other sites More sharing options...
Kassan1973 Posted November 20, 2020 Author Report Share Posted November 20, 2020 Thanks Adam ill try that i had similar thoughts , if it works oK i will run a dedicated earth for headlights straight to battery , as battery was relocated from driver to passenger side of car . Regards Dean Quote Link to comment Share on other sites More sharing options...
Kassan1973 Posted November 22, 2020 Author Report Share Posted November 22, 2020 Hi Adam its a strange one tried several earths to headlights .body and engine same issue, it doesnt seem isolated to the headlights as i had the interior fuse out also to try and isolate things and everytime i push the interior light fuse back it , this also triggers the pump and isc , i will remove my cold air box to see if i have missed an earth wire during my battery relocation and let you know. Cheers Dean Quote Link to comment Share on other sites More sharing options...
Kassan1973 Posted November 22, 2020 Author Report Share Posted November 22, 2020 Another update , if i have the crank sensor disconnected at engine problem goes away, if its an issue with stray current would it only be induced if there is a full circuit or should it still trigger if sensor connected?I am using some HD shielded microphone cable for the crank and cam sensors which is grounded as per instructions at the ecu end, could the cable be an issue? or sensor perhaps when car is running there are no issues at all scratching my head ATM? Dean Quote Link to comment Share on other sites More sharing options...
Kassan1973 Posted November 23, 2020 Author Report Share Posted November 23, 2020 HI all Any other suggestions on this ? Cheers Dean Quote Link to comment Share on other sites More sharing options...
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