Load Starter Tester

Load Starter Tester

Starter motor clicks and wont turn when engageed on flywheel?

The starter motor on my 85 Pontiac Fiero passes tests on bench testers, and spins and extendeds if you hold on to it while it hooked up to the car, however when it is bolted up to the block and engages the flywheel all that happens is the solenoid clicks like mad. The battery is good, that has been verified, I have just replaced the battery cable down to the starter, we added a ground using jumper cables, that also failed to help. Curious if this is an alignment issue, of if perhaps the solenoid is failing only under the load of engaging the flywheel. The starter is new a couple days ago, and the solenoid is less than a month old.
**EDIT** I should have mentioned that it push starts and runs just fine.
Well problem solved, survey said bad ground. Added a new ground from the starter motor to the ground post under the rear decklid and she fired right up.

Confirming the batteries condition for voltage and amperage is a good first step. I know you say that you checked it, but did you put a "load test" on it? Only a load test will give you an accurate view of the real condition of the battery.

And it is good that you changed out the positive battery cable to the starter. I would also recommend that you change out the negative cable and any grounding straps as well. A bad ground is a common condition that can cause this symptom.

If the starter motor seems to work while on the bench, check the Bendix Spring. That is the geared part that should engage with the flywheel. If it spins but doesn't extend out to engage the flywheel, then you won't spin the engine.

If the Bendix does engage the flywheel, and the battery is good, then you may have a starter motor that simply will not generate the torque required to spin the engine.

Load Testing a Battery, Testing Vehicle Charging System and Testing Starter Motor Draw