Won't start; grinding noise.
 

I have a 1995 chevy blazer ls 4x4. I got it with a knock in the engine. I have reason to believe we have fixed to knock (my husband is a mechanic and he basically rebuilt the top half of the engine) Well we tried to start it to see if we fixed the knock and it wont start. Fuel pump is fine, can hear it turn on. No spark to the spark plugs. Firing order is right. Battery is fully charged, but alternate has a snipped wire ( however i do not think it is relevent because it started before with it the way the alternator is) I have a video of the grinding noise it is making. Starter was also starting to go out but it was rebuilt, flywheel is spinning fine.

blazer wont start - YouTube

<iframe width="420" height="315" src="http://www.youtube.com/embed/AFOUC6Vso2M" frameborder="0" allowfullscreen></iframe>

please help i start school soon!

If the flywheel is spinning properly i'd say that sounds like a weak battery/starter. Start by checking all your wires/connections to the battery and starter and check the battery itself. If all that checks out you should pull the starter and have it tested.

My husband says its not getting spark. He said he thinks the computer may have gone bad because when we hook up our OBDII scanner it says "link error"

That's a possibility, however the "grinding noise" you're hearing sounds to me to be the starter turning slowly.

If it's not getting spark start by testing the ignition system. What kind of scanner are you using? If it's just a cheap code reader it may be malfunctioning...you could take it to a reputable shop with a more in depth scanner (like a snapon modis, or GM Tech2) and they could diagnose the "link error" wether it's computer/scanner.

link error is most likely fuse blown on cigar lighter circuit sounds to me like it has no compression and spinning to fast, do a compression test

Get your ignition control mod tested that could stop giving spark

If the engine is actually spinning in that video, it sounds like there's no compression, could be the timing chain is off and the cam is not timed properly.

I'd start by checking valve operation with the valve covers off, make sure valves are closed for Cyl 1 when piston 1 is on TDC.

Step #1 check for compression (always good to do this at least once when you get a chance)

Step #2 get it sparking

Step #3 check fuel pressure

If it still wont start something went wrong when you rebuilt the top half of the engine

Definitely sounds like no compression. Possibly the rocker arms were tightened too far or too tight, holding the valves open. Try loosening them up a few turns and then crank it. Get the compression problem fixed, then deal with the ignition.

yeah we did a test and its not getting compression