Does battery condition affect common rail injection?

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CBG

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Apr 10, 2005
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I recently load tested the Varta battery in my W202 C220 CDi. It showed up as ‘weak’ despite being regularly conditioned with a CTEK charger and was only about three and a half years old. I suspect it has a faulty cell. I replaced it. It is no surprise that the car now starts in a more spirited fashion. However, unless I am imagining it: the tick-over is now smoother: it revs much more enthusiastically and has more torque. Even the radio works properly again without periodically turning Radio 4 into techno. So what is going on? Is common rail injection voltage dependent to that extent? :dk:


I suppose the other point to make is beware that CTEK type chargers can disguise a faulty battery. Arrange for a load-tester to be in your stocking this Christmas! :thumb:
 
When the nice man from Mobilo life was testing my car a few years ago I noticed that it said 10.5V too low when he was trying to start it. So I guess that the answer to the question is yes, probably due to a reduced reference voltage for all of those nice electronic circuits.
 
Goes to the oft quoted maxim that a high capacity battery in good condition [= able to hold a charge] is essential to the optimum operation modern electronic dependant automobiles. 3years plus = watchful waiting ---5years plus = renew
 
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New battery solved this problem. Merc dealer offered diagnostics (at a cost) Battery specialist tested battery, advised to replace ( it was over 6yrs old). £96.(for Varta 019) no problems since.
 
Thanks Gents. A month on and the car is definitely running better. It flew through the MOT emission test - only 25% of the emissions limit, which is not bad for an old-timer with 170K.

Might change the alternator regulator at the next service.
 

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