You're wrong about the ignition switch because obviously something is happening when it is turned to "crank". For your vehicle, you're right about the starter solenoid, but you're going to be mislead if you remove the starter for testing. That is by far the worst way to approach this.
Sorry that I can't stop myself from getting overly-technical, but without going into a long explanation, the faster a starter spins, the less current it will draw from the battery. That's why locked-up motors blow fuses even though they aren't shorted.
The problem with the little silver Nippendenso starters is the copper contacts in the solenoid burn away until they make intermittent contact. These starters can easily draw 250 amps or more when they're initially turned on, then once they're spinning, that current drops to as low as 100 amps. That 100 amps is what we find when performing starter system tests with the starter on the engine. Testing on-car also includes the battery and cables in the test. Those are responsible for way more cranking problems than are the starter motors, so you want everything included in the test.
When you remove the starter for a bench-test, it has no load on it so it's free to spin a lot faster than normal. It is likely to draw only 30 - 40 amps. It is real easy for that little current to get through the burned solenoid contacts, and that falsely makes the starter look good. You stuff it back on the engine, have the same problem, and go looking in all the wrong places.
With the starter on the engine, with the high load during cranking, it will draw much higher current. That makes the burned solenoid contacts show up easier. It is possible to get real slow cranking, but 99 percent of the time the symptom is you hear the nice loud clunk when the solenoid engages mechanically, but when it turns on electrically, it can't pass enough current, so the motor never spins. This always starts out as an intermittent problem, so releasing the ignition switch, then turning it to "crank" again, multiple times, will eventually get it to crank the engine. There's a contact disc that gets pushed against the two copper contacts, and that disc is free to rotate when the plunger moves. Eventually it will rotate to a spot that's good enough makes the contact and the motor spins. If ignored long enough, this will get progressively worse over weeks and months. In the case of my mother's '95 Grand Caravan, she lost count after cycling the ignition switch 700 times, and a blister on her thumb, but it did eventually crank and got the engine started. You can be sure I heard about that!
Most people just replace the entire starter, but there are repair kits available in hardware stores and farm and home stores. If you have a starter / generator rebuilder company near you, the contacts are available for about three dollars each, but there's a problem. Every one of these starters on Toyotas and Chryslers uses the same "battery" contact. The second contact, the "starter" contact, has three versions and there is no way to know which one you have until the starter is disassembled. These starters all interchange over multiple years, and they changed to shape of the second contact for some years. When you buy a rebuilt starter, it could have originally been used on a vehicle many years older or newer. To solve this, the hardware store kits come with four contacts. You use the "battery" contact, then you use the one of the other three that matches your old contact.
The next problem is there are three different length plungers with the contact disc. Two are used on the starters used on Chryslers. Those two kits are listed in the stores by model year, but again, if the starter was replaced years ago, you can't be sure you're buying the right kit. Fortunately the plungers don't wear very much so it's okay to reuse the old one.
Toyota uses its own plunger with a different length shaft from either of the Chrysler parts, but you can't buy that anywhere except through the Toyota dealer's parts department. They charge a real lot more for it than the entire kits from hardware stores. Chances are you don't need a new plunger, so you can buy either kit for a Chrysler starter and just use the two contacts you need.
Image (Click to make bigger)
Sunday, February 11th, 2018 AT 10:58 PM
