Under the hood, the engine advances slightly with each click. During this symptom the starter draws about 500 amps. Boosting had no effect. The starter was replaced. I drove off. Minutes later it failed in the same way. My mechanic then swapped two identical (high power) relays in the fuse panel. The van started right away. A couple of days later the exact same symptom happened and left me stranded. I removed the same relays (one of them appeared hotter than the other) and let them cool off in my hands and reinstalled them in the same location (no swap). After a few more (20ish) tries the motor cranked normally and started. Stranded time was about 15 minutes. It should be noted that the underhood temperature is usually high (but not every time) when this happens. When the starter is "engaged and not cranking" the dash lights do NOT dim. Any ideas? Thank you for your time.
My car has 265000 miles.
My car has an automatic transmission.
Hello. First of all, 500 amps is too high. Most starters pull 150-300 amps. With the other symptoms you describe, I am fairly certain you have a bad connection in the starting system.
Starting systems have two circuits. One sends a low amperage signal to the starter solenoid which then engages and allows a second, much larger amperage circuit to be connected directly to the battery. With 500 amps, I suspect there is a high resistance somewhere in the main power circuit for the starter. With higher resistance, a higher amperage is required to overcome it. This is what the high amperage indicates to me.
The intermittent nature of this problem also suggests the same issue. Electricity isn't something you can see or touch, and we can't look at a wire or connection to determine if it is bad. This is why we have test lights, multi-meters and amp meters. There are times when bad connections are obvious, and many times those obvious signs of a bad connection exist, but they still work. Any bad connection will inherently be intermittent and can be a challenge to pinpoint because of their intermittent nature.
Temperature is certainly a factor, but isn't by any means absolute. If the dash light doesn't dim, that simply means the starter isn't drawing any current. The question is: where is the high resistance? There are several methods to figure this out. A test light is often the best choice, but there are times when a voltage drop test will need to be performed. It will be best to find a qualified mechanic who will diagnose your problem and not just replace parts.
More often than not mechanics can diagnose a starting issue based on the customer description. Unfortunately, there are times when this doesn't work. This is when you need a mechanic who thoroughly understands electricity to test the system. Many think the simplicity of a starting system is a reason to discount such a diagnosis. But as you're experiencing now, you could really use someone who can figure out your problem.
My suggestion is to try another technician, perhaps one from YourMechanic. YourMechanic technicians are mobile and can inspect and diagnose your vehicle's starting issues at your home or office.
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