Jamesn Posted December 29, 2022 Report Share Posted December 29, 2022 Hi guys, woundering if anyone could help me have an rb20det in my mini truck has a link g4+ atom ecu, wastespark, megasquirt ignitor and powertune dash. I have had some problems of late regarding fueling but i have nearly solved this problem with my regulator and injectors needing cleaning but my next problem is the engine wont start at all or fuel fan and ignition relays wont click on I have tried plugging ecu in computer and comes up with "unable to connect to the ecu but usb connection is present. Please cyce the power to ecu" i have a blue led that comes on ecu so im pretty sure that it is getting power and swapped the relays still nothing except when i disconnect the ecu relay ground my fuel pump turns on, but now im noticing my ignitor on the outside is very hot to touch and also my coil pack is hot to touch, previously had spark before Also before i could spin the crank sensor to test the injectors and the fuel pump would turn on but now nothing like that seams all power is dead or is shorting out somewhere. Any help would be appreciated- havnt had any heating issues of coil packs or ignitors before. Cheers James Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 29, 2022 Report Share Posted December 29, 2022 Pull the ecu out of the car and power it up on the bench to see if you can connect to it then. This is the easiest way to isolate any wiring issues. You only need 12V on pin 5 and ground on pin 34. Quote Link to comment Share on other sites More sharing options...
Jamesn Posted December 29, 2022 Author Report Share Posted December 29, 2022 Thank you for your reply Adam, i took out as you advised and connected positive and negitive and to ecu and that powered it up and i got readings.. What would be the possible wires to look for if it is causing ignitor and wastespark to get hot and not registering with ecu? Cheers James Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 29, 2022 Report Share Posted December 29, 2022 I suspect the main ground would have to be missing. The ignitor would need to see a high voltage on the ign output pin to start passing current. The ecu would have the ign outputs connected to ground at power up so that would suggest the ground is missing or not actually ground. Try back probing the ground pins 26 & 34 with ecu plugged in & ign on and measure voltage between those pins and batt negative. Anymore than about 0.2V would suggest the ground is bad. You back probe using a needle or pin pushed down beside the wire until you feel it touch the terminal inside. Something like this: Quote Link to comment Share on other sites More sharing options...
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