Drac9 Posted April 17, 2013 Report Share Posted April 17, 2013 We have a v88 ecu in an open wheel car running a crate LS7. We wired it up and had it starting and running pretty well on a base map. We are having an issue with the alternator getting hot to the touch after running for a few minutes. We removed it and had it tested to verify it was good. On reinstallation we discovered our kill switch did not actually kill the positive lead to the alternator by accidentally grounding the positive cable to the same ground lug we are using for the ecu. After doing that we checked all of our fuses and such and it seemed ok. We started it up and it was richer and seemed to be running a little "off" We checked the injector outputs with a noid light on that bank and found one injector was constantly commanded on with a VERY bright noid light. We disconnected the ecu and found that it was still being commanded on. after troubleshooting the harness for a while we didn't find any issues but eventually it just started working again on its own. This brings me to the issue at hand. Before we started the car we tested all of the injector and coil outputs and had good, bright lights on the noid lights. When I test the injectors now the light comes on but is probably half as bright as it was previously. We have verified we have 12 volts at the injector connectors. We have checked continuity on all of the grounds and have less than 1 ohm resistance. The sensors all seem to be reading correctly and there are no ecu errors. I'm guessing something is shorted internally in the ecu. I opened the case and didn't see any burned traces or anything like that. Any thoughts or ideas? We have a race Saturday. If this needs to be sent it does it have to go to NZ? Quote Link to comment Share on other sites More sharing options...
Drac9 Posted April 17, 2013 Author Report Share Posted April 17, 2013 Ok, did a bit more troubleshooting. We did find a short on the number 6 injector wire in the harness and repaired that. We also put a new battery in and that solved all of the alternator hot issues. The noid light is still dim when testing it compared to when we tested previously. If we ground the injector wire directly it goes to full brightness. Any ideas? Quote Link to comment Share on other sites More sharing options...
Simon Posted April 18, 2013 Report Share Posted April 18, 2013 Check the grounds to the ECU are in good shape as the earthing of the injectors has to be done through these. Also check the injector settings to make sure they are set correctly, saturated if high impedance and peak and hold if low impedance, Check the peak and hold currents too. The fact they flash indicates the hardware of the ECU is ok. Quote Link to comment Share on other sites More sharing options...
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