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Old 05-29-2013, 08:08 AM
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Jethrow Jethrow is offline
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Join Date: Jul 2010
Location: Perth, WA
Cobra Make, Engine: FFR Mk4 Roadster, LS3, TR6060, 8 3/4"
Posts: 432
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Default Engine Slow Cranking

Wow - this electrics is tricky.

So my latest issue is that now my engine (LS3) suddenly cranks very slowly.

I am not quite ready to start proper but I have been cranking the engine in preparation and to date the engine has been cranking over well. But now all of a sudden the engine turns over very slowly when cranking.

It seems a very deliberate slow crank like the ECU is controlling it like that, but maybe I am off here. The battery is not flat (12.8V when tested) and to check I also jumped it from my other car but to no avail.

The only changes I have actually made to the car since the last successful cranking was to connect up the O2 sensors, and to remove the spark plugs for hopefully even faster cranking (I was hoping to see some oil press on the gauge before a real start).

I have been disconnecting the battery earth lead when not playing with electrics so I trust this is not bad for the ECU...

Anyway, I cannot see what I have really changed to cause this.

Have I burnt out the starter motor? I would have thought I would flatten the battery first, but I have not cranked so much for that to happen.

Have I failed my battery? It does test at 12.8V, but maybe that does not mean it has enough CCA left to spin the motor?? As I said before I did also jump start to no avail. Maybe I need to remove the battery from the circuit and just use another?

Should I pull the starter motor and inspect?

I believe I have good battery connections to starter motor and ground, and the motor has spun over properly before.

This is confusing me ...
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Tim
FFR Mk4 Roadster
HSV Clubsport R8

Last edited by Jethrow; 05-29-2013 at 06:39 PM.. Reason: reworded for clarity of problem (I hope)
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