94 s10 blazer 4.3l v6 vortec engine troubles

[panther1583]

I recently purchased a '94 s10 blazer with 4.3l v6 vortec engine. i replaced the distributor as it wasn't firing, and having replaced with a used distributor, the icm won't ground properly, so to get it to start i have to dump a little gas into the intake. after it fires and starts, it runs fine, so i know that i'm not getting a good enough ground. that problem is a simple fix, no biggy. now, i have a much bigger problem! i tried to get the engine to fire so i could figure out why it was idling high, and having no gas handy i used a shot of carb cleaner, big mistake. when i tried to turn it over i noticed a very loud clunk about every 6th rotation, where it would stick for a second, then crank again, but slowly. darn. give up for a week. now, dump a little more gas into the intake, clunk, rotate, fire, runs, clunking a little at first, but once it gets running normal, well, as normal as it has since i bought it, can't here the clunking any more. figure, ok, maybe if i loosen the distributor, tweak it a little i can get the idle a little closer to where it should be. turn a little too far, car dies. ok, no big deal, restart, try again. no go. now, all i get is a very loud screech from the starter, won't even try to turn over. i'm afraid that the engine has locked up. can anybody help? a friend of mine says the reason for the clunk in the first place could have been the timing being off and one of the pistons pushing up too soon. possible?

[Chris Stewart]

Sounds like you have a pair of plug wires swapped.
The "clunk" is likely the wrong plug firing way too soon. This event can get so bad the engine turns backward against the starter rotation and can cause great harm. Your "screech" is likely a broken tooth off the flywheel from the backward start.
You might try re-checking your sparkplug wire placement on the distributor cap, check the "starwheel" inside the distributor for a broken "star".
You might be able to get starter engagement by rotating the crankshaft a coupla degrees to get past the missing tooth but it's likely more teeth will get broken if you don't address the ignition problem.

[old_master]

Might want to check fuel pressure also.

[panther1583]

Originally Posted by Chris Stewart

Sounds like you have a pair of plug wires swapped.
The "clunk" is likely the wrong plug firing way too soon. This event can get so bad the engine turns backward against the starter rotation and can cause great harm. Your "screech" is likely a broken tooth off the flywheel from the backward start.
You might try re-checking your sparkplug wire placement on the distributor cap, check the "starwheel" inside the distributor for a broken "star".
You might be able to get starter engagement by rotating the crankshaft a coupla degrees to get past the missing tooth but it's likely more teeth will get broken if you don't address the ignition problem.

I checked the flywheel and as you suggested, it is completely destroyed. Fun times for me! Thank you for the information. As far as the wires being swapped, I looked everything up, and they are all in their proper positions, so that 's not the problem. I work 3rd shift, and I don't have the money to put it in the shop. I know that I'm going to have to replace the flywheel now, but if you have any other suggestions on what could cause the starter to eat at the flywheel before i have to replace it a second time, I would be very grateful. I set engine to tdc, realigned the distributor (which didn't have a broken star), and made sure that all the wires were in their correct positions. thank you.