02 Sonoma problem

My dad parked his 02 Sonoma after it ran fine. Tried to crank it that night, and it would turn over but refused to crank. Today I checked with a spark tester and we were getting the light on when the plug would fire, but it seemed somewhat dim (maybe just me, can't recall how bright it should be). Checked fuel pump...had good pressure. Chjecked fuel filter and seemed clogged/restrictive. Bought another one, still won't crank. Checked exhaust...no problems there.
Crazy thing is while it's turning over, it seems every now and then to 'bog' like something's mechanically holding the crankshaft back.....then releases and bogs again. Even with my Ranger next to it running with jumper cables keeping his battery up. We finally tried cranking it so much that smoke rolled out of the starter motor.
My question is.....is it the starter doing all this, or did we maybe burn the starter up due to an underlying problem? We took Serp belt off and checked all pulleys and turned motor over with just the crank being turned and it still bogs. Anyone got any ideas?............it'll be Monday or so before he gets the new starter. I just wonder what it could be if it still won't crank. Thanks. :banghead:

Welcome to AF. Pull the plugs, the engine may be loaded with raw fuel, 4.3 I assume. Does the FP gage show it holds pressure, key on not running, will start on starting fluid, this is all basic diagnostics, How much fuel pressure, 60 is required. Yes either the loaded engine or extensive cranking cooked the starter.

You're correct 4.3. We tried starting fluid with no luck. Pump pressure great with switch on (not trying to turn over). Tried not to make the post too long.....left out all little tests. Main concern is the dragging of the engine. Starter burnt up, but was it cuz we tried it for too long at a time? The drag happens without the serpentine belt attached to anything else, so nothing else is snagging it. starter and crank going it alone and still it catches a snag then turns over again.:runaround:

No way to diagnose this from here, did you pull the plugs and try it, as suggested, post back when you do this.

plugs look really good. Changed them out while we were troubleshooting anyway. In case anyone here has this truck and hasn't done it yet, getting to these plugs with thick arms is a nightmare. Had to temp remove a lot of stuff and at one point jacked the frame. Plugs all looked really good though. What did u mean by pulling them? Checking them? Got new ones now.

What exactly do u mean by pulling them?...........Any other ideas?:confused:

Maybe it is me? remove the plugs and see if the engine turns over more easily, no binding like you felt before, as I said in post #2 , it be locking from raw fuel in the cylinder or another internal type of problem..

...Pump pressure great with switch on...

Did you check fuel pressure with a gauge? Must be 60psi MINIMUM for the engine to start. Have you checked the distributor cap and rotor for moisture?

66 is pressure on gage I bought from Autozone....not guaranteeing the quality of the read from it. Seems it has more a distributor pack than a cap.......though we didn't notice moisture or anything out of the ordinary when we checked for an ICM. Changed the starter and got the same thing. Any other thoughts???? He loves HIS truck. Loves GMC:popcorn: