Re: engine stuttering
Posted: Sun May 26, 2013 10:31 pm
It is likely that your engine's problem is intermittent, maybe one cylinder isn't hitting every time, like it is losing spark sometimes or not firing correctly because the fuel mixture is too far rich or too far lean. At low RPMs, it would be much more noticeable, because the time the engine can recover from this power-loss is longer until the next cylinder can catch it back up. At high RPMs, a few lost power-strokes every few dozen revolutions or so would be easily missed.
Also, at idle, your engine is making just enough power to turn itself, so a little loss is really noticeable, whereas at high RPMs the engine has greater power available to it, and most importantly it has more inertia trying to keep it turning. Think of it as trying to roll a tire up over a bump, if it is moving fast it goes over it easily, if the tire is barely rolling, the bump can stop it cold.
When you are looking at the plug wires, check them at night and look for spark, but also go over the whole length of the wire and look for cracks, splits, or discoloration, like brown/yellow spots, black areas, or an off-white sugary powder on them -this is carbonizing caused by the high voltage spark arcing to ground.
The Beretta community is really one of the most supportive and also most entertaining I've found. I don't much bother with the sites for the other cars I own. I think the Fiero sites might be the only other ones even close, some of them really are pretty good too.
Also, at idle, your engine is making just enough power to turn itself, so a little loss is really noticeable, whereas at high RPMs the engine has greater power available to it, and most importantly it has more inertia trying to keep it turning. Think of it as trying to roll a tire up over a bump, if it is moving fast it goes over it easily, if the tire is barely rolling, the bump can stop it cold.
When you are looking at the plug wires, check them at night and look for spark, but also go over the whole length of the wire and look for cracks, splits, or discoloration, like brown/yellow spots, black areas, or an off-white sugary powder on them -this is carbonizing caused by the high voltage spark arcing to ground.
The Beretta community is really one of the most supportive and also most entertaining I've found. I don't much bother with the sites for the other cars I own. I think the Fiero sites might be the only other ones even close, some of them really are pretty good too.