Vindicare Posted October 8, 2013 Posted October 8, 2013 Hey guys, I'm not always the brightest spark, but I'm having a problem with my earth to my ecu. I check the loom earth, it reads under an ohm, I made sure it's under an ohm to the engine block. Now my dilemma is I'm getting a reading of 13.6 ohms at the ecu plug, which is causing the ecu not to start. Can anyone please offer me some advice on how to fix this problem and let me move on to the next one? Cheers Aaron Quote
Six_Shooter Posted October 8, 2013 Posted October 8, 2013 What do you mean by "loom earth"? The point where the ground wire to the ECM is attached to the engine block/chassis? What is the reference point? Battery terminal, chassis, engine block? Without knowing the reference point, it's hard to say if or what is an issue. Quote
nizm0zed Posted October 8, 2013 Posted October 8, 2013 You can never have too many earth points!!!! Obviously there is the usual problems which im sure you have already done, like make sure the earth wire bolts down to a cleaned surface ect. Make sure what you are grounding to isn't isolated from the rest of the chassis, like through rubber engine and transmission mounts. Check your engine to chassis earth strap, make sure its mounted down securely on clean surfaces. Consider running an ECU dedicated chassis to engine block earth at the same point you are grounding the ECU on the block. Quote
Vindicare Posted October 8, 2013 Author Posted October 8, 2013 There is 2 earth connections in the ecu loom, one is on chassis but is only an earth for the main ecu & cdi relay. The other is on the head. These 2 earths communicate at under an ohm. It's got me buggered, I'll cleans the earths up and try again tonight. I have benn referencing to main engine ground which also communicates at under an ohm with each Quote
dazzed Posted October 8, 2013 Posted October 8, 2013 thats not a bad earth problem that is a voltage leak to earth , if resistence is that high, voltage leaking through a sensor, either a faulty sensor or a wire incorrectly fitted, put your meter on voltage turn on ignition, put one lead in raditor coolant other lead to earth should not read any voltage if it does read you have a faulty coolant temp sensor , or keep disconnecting engine sensors including injectors one at a time untill the resistence value drops that will aid in isolating your voltage leak, voltage leaking through a sensor into the cooling system will corrode everything eventually the water pump impeller blades will disapear and cause the engine to overheat causing a lot of head scratching, hope this helps cheers, Dazzed Quote
Vindicare Posted October 8, 2013 Author Posted October 8, 2013 Thanks guys, I'll give all this a try tonight, if anyone has any other suggestions keep them rolling in. Thanks! Quote
Vindicare Posted October 9, 2013 Author Posted October 9, 2013 Okay fk knows what I've done, not sure how to get comp goin, fuel pump relay is not getting power which I find odd, might have to attempt to bypass old alarm, perhaps it's not letting the relay get power, or god knows. God I hate wiring Quote
Vindicare Posted October 9, 2013 Author Posted October 9, 2013 didn't have ignition source connection for ECU, it would appear that i've forgotted where a wire goes since i sent the ecu away. Jumpered to a ignition source and finally have power to the computer and fuel pump. Next step, recharge battery jump pack and keep on chugging along. old ign wire went to a plug which connected to nothing, go figure. but i'll find a better place to tap in to the good one . Im super hopeful it starts without too much prompting, was crackin for a little bit. Quote
dazzed Posted October 9, 2013 Posted October 9, 2013 didnt even think to ask what car which efi system we are talking about,?? Quote
Vindicare Posted October 10, 2013 Author Posted October 10, 2013 Okay I think all the problems I'm having is from tapping in to the wrong ignition source, can one of you guys tell me which colour wire to tap into and where a abouts? From the wiring diagram should it be the white/red wire from the ignition switch? Quote
NZeder Posted October 11, 2013 Posted October 11, 2013 White with a red tracer in the zed is usually a feed from the fusible links via the alternator/regulator charging wire. So that would be power to the switch not the switched ign source. The ignition from the switch is usually a Black with White tracer Quote
benny Posted October 11, 2013 Posted October 11, 2013 Okay I think all the problems I'm having is from tapping in to the wrong ignition source, can one of you guys tell me which colour wire to tap into and where a abouts? From the wiring diagram should it be the white/red wire from the ignition switch? grab a test light and find it on the back of the barrel. Quote
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