If the block is grounded to the battery, that is enough. It doesn't also have to be grounded to the frame. It wouldn't hurt anything if it was.

If all of your wiring checks out ok and the starter still does not spin fast enough with only the starter itself powered, then the starter has to be the problem. I would return it and get another starter from a more reliable source.

 

I re-read through this post again. Since you've been changing so many starters... Maybe you might try taking the starter off the other blazer and trying it on the one that won't start.
And another weird problem I have on my blazer is... that if it cranks slowly for more than 5 rotations. When my blazer starts it kind of leaps forward alittle. Something drags inside my tranny. It's an automatic, but the previous owners said the had the trans rebuilt. You might try and see if it turns over faster in neutral. Just an idea?.?.

 

Hmmm. I might have to try that with changing the starters. I'll also give it a shot starting the car while in neutral. Can't hurt. I'm at a loss here I don't even really know what to check next.

 

Ok guys the last thing that I've been able to do with this is put the starter from the good blazer on the bad blazer and it still spins slow so it's not the starter itself. Is there anything else that when not working properly can zap power? Or something that is supposed to provide power when cranking the motor that could go bad? That's all I can really think of. We're trying so hard to not have to take it to an actual mechanic because we don't have the money.

 

Could Zash's ignition area(where the key goes in), contacts be malfunctioning?

 

Anybody??? This is getting a little rediculous that we can't get this car back on the road.

 

From what Ive read you still did not take battery out and load test it at a parts house,that is the thing that is all your troubles

 

You must have missed the part where I put another battery in it from a good working car and it still would not start. I put a real good battery in and it wouldn't start so the problem lies elsewhere.

 

Here's something I haven't seen you try yet. Not sure if it will help narrow down the problem but try starting it with another vehicle jumpered to yours. For some reason it sounds like you aren't getting all the juice to the starter it needs.

 

We've tried that but thanks for the help. When the car is being cranked the voltage drops to about 8 volts down from 12 but I don't know why. I don't know what is wrong that can cause that to happen.