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Weak spark problem

Oldcomguy

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12.42 is not that great, put the battery on charge, a healthy battery is around 13.5v. Try jumping from another battery.
I have tried with fully charged battery .
13.5v would be when car is running at minimum.
 

Oldcomguy

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I'm not testing cranking voltage drop, the voltage drop was at the coil there was minimal voltage drop at the battery.
 

Skylarking

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I'm not testing cranking voltage drop, the voltage drop was at the coil there was minimal voltage drop at the battery.
Your earlier statement indicated that on cranking the voltage at the couil dropped.
So just tested the power to the coil, it was 12.42 the same voltage as the battery but when I cranked the motor it dropped to 8 something volts.
As battery volts is supplied to the coil via the ignition circuit, it must reflect battery voltage... And battery voltage will nominally be between 9 volts and 10 volts when cranking.

If you are getting different volts at the battery and the coil when cranking, then you have some odd issue so i'd check the ignition circuit components that feed the volts to the coil (if thats the case)...

The battery may seem full according to your charger but it can still be faulty even when it cranks. Is the crank slow? Also, 8 volts at the battery on crank seems a little on the low side so i'd get the battery load tested as well as looking at the coil resistance and lean resistance among other things mentioned..
 

Oldcomguy

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Still haven't sorted this out as yet due to time issues.
Have fully charged batteries available either of the charger or from other running cars.
This car has had this happen before.
We have found continuity between the ignition side of the main fuse near the battery and earth with ignition on, also with ignition off it has continuity when the high beam is used.
Surely this can't be correct?
 

Oldcomguy

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Update, it was a weak coil in combination with fouled plugs.
New coil and sanded the plug gaps and it now runs ok on LPG but still need to work out the fuel issue and awaiting new injectors.
 
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