Bronco 2 starter problem

[Spartan]

Okay.

89 Bronco 2 XLT, 2.9L Manual transmission.

I turn the key, the starter grinds. The spacer plate is intact and positioned correctly. The starter teeth and the flywheel teeth are all fine, no chips or missing teeth. The starter bolts are tight and the main cable from the solenoid to the starter is new looking, with no bulges or corrosion. Motor turns over just fine by hand, and is push startable. bench testing the starter with direct battery power kicks the bendix out all teh way, and spins correctly, it does not wind down like a bad armature would.

Voltage readings:

Battery voltage: 11.48V
Verified post to post, and positive to ground.

Battery to battery side of solenoid: 11.48 Volts

Battery negative to starter side of solenoid when cranking: 6.5 volts or so, creeps to 9 volts if the key is held down.
Voltage is the exact same as read from the lug on the starter to the bell housing

We swapped another solenoid in from an explorer, and it just clicked...no attempt at turning over that time, just a *Click* Swapped the other solenoid back in, it ground again

We cleaned all the contacts on the solenoid, the starter, and the battery, no difference in voltage or symptoms.


The main engine to battery ground WAS NOT touched yet, it is our next project.

My theory is that the starter is fine, I'm having a power delivery problem. It has enough power to kick the bendix out all the way and spin, but not enough to keep it held out, causing it to grind on the flywheel.

Any Ideas? I need Help soon, my 88 Thunderbird is going into storage!

*also posted in the 2.9 forums*

 

[cobrasplash]

i would crank the motor over by hand to see if its binding at all, check the cross member to see if its rusted out and not holding it where its suppose to. My cross member was rusted out on one side and took out the throw out bearing as well as causing the starter to bind when trying to start it