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Discussion Starter · #1 ·
i put a thread on a few wks ago about my cav sri 8v not starting later found out my earth had snapped engine to g box replaced that and found my fpr and my ecu had fried changed them still no joy.took it to the garage a wk ago they said my crankshaft sen was away they put a new 1 in still no joy they saud there is a slight spark from the coil but not enuf to start it,there having to get 1 of there mates with the same car to strip bits off it because they dont no whats wrong with it anyone any ideas please.....
 

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When your Engine earthing wire snapped, and any subsequent starting attempts made the heavy current required (200-300amps) couldn't find a return path to battery directly so the current flew through whatever other smaller wires connected up through ECU, sensors, lights, anything that would allow the earth currents to return to battery via these smaller wires through your loom wiring must have not only caused the damage to ECU and other sensitive instruments, but possibly burned completely (melted) any thin earth paths or thin wires through which heavy earth currents went. So the thing to do now is to ensure that any instruments and equipemnet like ECU, ABs, has proper earth continuity, and by proper earth continuity I mean absolutely Zero ohms paths, give and take half an ohm.

Refer to Haynes manual, check all the points on the ECU connector whre there should be earths, connectors may have got melted pins, wires may have melted inside the sheath so the only way is to provide seperate new earth leads to any point missing a earth connection.

Putting it simply, a starter motor requires a heavy starting current of a few hundred amps so consider your main earth wire that snapped as a 100 ton bridge, if that bridge braeks, you can't use a smaller 10 ton bridge to pass a heavy tank weighing 100 tons over a 10 ton bridge which if attempted will collapse and break.
 

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Discussion Starter · #7 ·
got news bk from garage they dont no whats wrong the only thing he said is that their is aplug with four wires hanging loose and its getting a live feed
 

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the garage is useless by the sounds of it

the crank sensor replacement was probably due to the ecu flagging a code 31 which is totally normal with the engine off and any decent garage should know that

if u have spark and fuel and compression it will start

you have fuel, which means the ecu knows the engines turning over and has turned on the fuel pump relay so u can rule those out, the fact u have fuel means the ecu will also be trying to spark the fuel mix, so thats the next port of call, coil, leads, dizzy, plugs etc

a compression check wouldnt go wrong either
 
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