Weak battery question

[Ghoste]

From reading mystery misfire posts over a number of forums, I was just wondering if a weak battery can affect spark output?  I'm talking about a battery that is maybe capable of holding enough charge to start the car and even run normally but as soon as a load is on it (high rpm acceleration wot type of load) it begins to fail.  Is this a possibility with some of these stumbling and misfire questions or am I not thinking it through properly?

[Chryco Psycho]

if it has enough power tooo start the car the ign draw shouldn`t be effected unless the car will not start again after running for a while

[Ghoste]

So what do you think is causing a lot of them Neil?  It seems like there are so many cars out there that start and drive fine but as soon as they stand on the throttle, it starts to sputter and misfire.  Most of them seem to have new carbs and or tuneups and so on.  Why are they all breaking up like this?


It may not be the epidemic that it sounds like when I re-read this but it does seem like I keep hearing the same sort of question lately.

[Chryco Psycho]

it may be too far advanced , the engine will misfire if over advanced under load or the other possibilty is it may have nothing to do with Ign , & may be fuel related & have too rich or lean accelerator pump shot or jetting or float level or fuel pressure etc

[Ghoste]

So each one is still unique to the vehicle.  I was just wondering if maybe there was some common thing everyone was overlooking.

[cudaken]

 Could be the ALT is weak and not have suffcent voltage to fire the plug when under load. Friend has a 440 that is bulit. Had a 750 Holley on it and under load it would miss out and foul the plugs black. Told Eric it was not the 750 Holley, but not listen (I got the 750 ) and he went with a Edelbrock 600. Hum same problem?  Gave him a old Alt I had and problem was gone? Had his tested and was only making 12 volts.

But as Neil said there are many things that can cause the problem's you listed.

                                Cuda Ken