I will test the resistance from the negative to the grounds tomorrow.

Since I put the bigger cable and ran it to the starter the car was much closer to starting. It fired a couple times but would not actually fire up. The starter spun faster than it had been but still not fast enough. I'm wondering if the ground cables need to be replaced too. I will test tomorrow and see what I can figure out and hopefully it will crank up. I'll let you guys know what happens and again thanks to everyone who has taken the time to try and help me. It means alot.

Zach

A large voltage drop in the system would cause other things to not operate properly as well. As in, it may not fire the injectors or give proper spark at such a low voltage. The ground is practically the only thing left.

I tested the resistance just now from the negative to the block and there was very little resistance. It went from 5 ohms to 22 when I had someone spin it over and I did see a 30 but my old man says that's not enough to cause the starter to not spin at the right speed. I just can't seem to catch a break. I was sure swapping that big cable today would have done it. Like I said it helped but it didn't get the car to start.

There has to be something rather large shorting out while the starter is cranking. Now that I think about it, that really is the only way to explain what is happening since the voltage drops at the battery as well. If you had a high resistance somewhere along the circuit, the voltage shouldn't necessarily drop at the battery as well.

But what could be shorting that would zap power to the starter? Could it have something to do with the ignition swith or something of the sort?

I'm not sure what it is, but if the voltage drop does not occur using the same battery in another truck, something is causing a heck of a draw on the battery in your truck.

What else stays on when the ignition switch is turned to START?...lights.....what else?

Can the ignition swith be by-passed by using a remote starter switch or applying +12V to the solenoid terminal using a length of wire between the battery and the solenoid terminal on the starter?

Thinking while typing and how to isolate just the starter.....

You can disconnect the power wire to everything else in the truck but the starter and jumper the large terminal to the smaller terminal which has the wire from the ignition switch. This should kick the starter to life. If it still shows the same voltage drop and associated poor starter speed, then the starter is to blame. If not, you have a draw in the system.

The schematics for the ignition switch can be found in the link at the bottom below my signature picture.

I haven't had to change the starter on my blazer yet. But on older chevy's I always had to shim the starter. Most remanufactures clean up all the mounting points on them and take metal off of the mounting points in the process. If there are shims.... I've personally not put enough shims in and it coused the starter to drag real slow. But another thing to consider... Even though Autozone test the starters they are just testing to see if they spin, NOT under a load. Most electrical problems show under a load.
I'd check your ground from your engine to the frame also. The starter grounds through the block. I doubt it'd be a problem in your +battery cable or fusible link. But if you had any electrical problems before this. You might try changing the cable ends on the battery.
My blazer cranks slowly. But that's on the original starter with 200,000 miles. LOL!

I'll be checking some more stuff out tomorrow. I didn't get a chance to work on anything today.

I'm seriously running out of ideas. Here's the thing with the starters...the original starter that started spinning slow actually tested good but it actually started failing to engage the gear, so we put another on and it did the same thing. It would spin slow and not fire, so I took that one back and they tested it and it tested good. But they gave me another one anyway. That one has done the same thing so I don't really see how it's possible for the starter to be the actual problem. I was going connect just the big wire to the starter and run a wire from the starter to the battery and see if it spins the right speed with no other electrics running.

I need this car running like now so I really need to figure this out soon.

I have another question though. Is there a ground that actually goes from the block to the frame on these blazers? The reason I was wondering is because there is a ground that runs from the - side of the battery to the frame...and another from the - side of the battery to the block...my old man said that should be enough but is there maybe another ground I haven't checked?