Why does my 1993 Grand Prix turn over to slow to start even if you jump the car?

Answer 1

I'm not familiar with your make and model, but the problem you describe is not uncommon with any vehicle, so this answer will be generic. There could be several reasons for a slow cranking speed, and I'll try to discuss a few of them. 1. A common [possibly the most common] reason for slow cranking is that the flow of electrical current is being "resisted" by something in the electrical system, and the most common source for that resistance is CORRODED BATTERY TERMINALS amd TERMINAL CONNECTOR CLAMPS. Although the lead from which the terminals and clamps are made is more resistant to corrosion that most materials, the harsh environment of the engine compartment and the sulfuric acid battery electrolyte combine to accelerate corrosion. The corrosion oxides, which form on the contact surfaces of terminals and clamps, are very poor conductors of electricity, and therefore "RESIST" the flow of current. As it take a great deal of power to crank an engine, the starter draws a lot of current, and if it cannot get as much power as it needs, it will only turn as fast as the available power allows. 2. Other locations at which this occurs, though not as often, are the terminal connector bolt on the starter solenoid[s], or on the starter itself. In both one and two, the first fix is to carefully and completely remove the corrosion [special round wire brush kits are available at most auto parts supply houses], clean, and apply a corrosion inhibiting film [special, expensive silicone lubricants, or ordinary grease or oil] on those components. Sometimes however, the corrosion can penetrate into the connector eylets at the cable ends, and cannot be effectively cleaned which requires that the battery cables be replaced. 3. Another cause can be that as wear of the carbon "BRUSHES" in the starter motor occurs, an accumulation of "carbon dust" interferes with the contact of the brushes with the copper commutator contacts on the armature. The reduced brush contact results in RESISTANCE which in turn reduces the amount of current which can flow through the starter, and weakens, and thus slows the starter. 4. Another cause can be wear of the bushings [bearings] in the starter which can cause binding and drag, which can slow the rate of starter rotation. Sometimes the wear can be so bad that it allows the spinning armature to literally "DRAG" on the frame of starter, further reducing the spin rate. 5. Another cause can be drag induced as the result of misalignment of the starter to the flywheel teeth. In the "old days," this even occured in the auto assembly plants, and they corrected the problem by inserting "SHIMS" between the starter and the engine flange to which the starter was mounted. These are the reasons which I am able to recall, and there are surely more which I have overlooked. Check the current draw of the starter. If the current draw is too high there is a real possibility that the starter bushings are worn. If that's the case you may have burned the armature. Remove the starter and have it tested at a reputable auto parts store that has a test machine.