94 Blazer won't start

Hey guys i've been searchin all thru the site n i cant figure out the solution to my problem...

1994 s10 blazer 4.3l vortec 180k miles
The thing is, it had previously been running like crap misfiring, stumbling, stalling. It would still start right up no problem. After running it at idle for about 10 minutes one day, it wouldn't start up again. So, I went and spent $300 on a new CPI injector unit and got that all installed.
No change.
It will crank and crank but wont turn over.
I've checked fuel pressure, everything is where it should be.
Spark seems to be good, new plugs(fouled quickly but i cleaned them), cap and rotor. Could I possibly need an ignition coil even though there is a good amount of spark?
New EGR valve, Battery, Alternator...
What else would stop it from starting!?!?
Any ideas on this situation? One day it starts up fine, the next, nothing??
I'm at a loss and have no idea what's going on....going crazy!
Any help greatly appreciated.

Had the ignition module go out on my 93 a few months ago.(Random starting, would not start until set for a few hours) I was fooled into thinking it was a fuel problem as I could get it to hit on starting fluid. It turns out it was not firing strong enough and was firing randomly. Replaced coil and module. No problem since.

What's the fuel pressure?

Key on with the engine off.

What's the fuel pressure?

Key on with the engine off.

Last time checked seemed to be plenty it was 58-60

Would it hold the pressure, or would it bleed off quickly?

It would hold steady, I've yet to check compression again because I did an oil change and the old oil was full of gas. Who knows...

It would hold steady, I've yet to check compression again because I did an oil change and the old oil was full of gas. Who knows...

That is a sign that you have to replace the cpi injector and the nut kit inside of the plenum.

he already said he replaced the cpi injector

CPI and Nut Kit both replaced recently...I'm pretty sure its not a fuel problem.
First, the nut kit went, replaced it, then it worked fine. Next, it starts having similar problems but worse than before. Thats when I got the new injector. I'm still not sure if will run smooth or not when and if I get it running. Ignition module is out of the question, right?

If you have gas in the oil, you bet your bum it is a fuel problem.

Oh yeah get this...NEW PLUGS AND WIRES did the trick! How crazy is that?? Stilling running rough, but gonna run the computer and see what codes it throws out. Hopefully it'll be back to normal soon. I'm just glad it finally STARTS. Now I won't have to tow it.....=)

You need to get the timing set back to zero with a timing gun and the timing wire unattached.

Set the timing to zero and reconnect the timing wire.

Also, have you ever replaced the cap and rotor?

You need to get the timing set back to zero with a timing gun and the timing wire unattached.

Set the timing to zero and reconnect the timing wire.

Also, have you ever replaced the cap and rotor?

True, I must fix the timing. The cap and rotor have been replaced not too long ago (1 yr?) . Do you think it would be good to replace them again? Also, do you think any sensors could be a problem? MAP, Throttle position, Air control, EGR cleaning, etc? Thanks

Make sure the timing is set properly and move on from there.

Got the scanner today...gonna see whats up with this...thanks again

Well guys, I can't believe it but I replaced 2 sensors today...Throttle Position and MAP.....didn't seem to do much. However, my friend had the idea to disconnect the EGR, and its worked! It's running like a champ right now! Any problems with misfiring, low power, stalling? DISCONNECT EGR. All my problems are solved right there...

I will attempt to clean it sooner or later, and if it starts running rough again I'll know just what to do. =)

You see, what was happening with all the blow-by thru the intake, the oil and gas were getting mixed together. The EGR started screwing with the whole system (b/c it gets stuck open) and tells the computer to put more and more gas in. This causes it to misfire, flood out, lose power, and stall.

Next step might be to rebuild tranny and motor...who knows...

Clean it tomorrow.

Having your computer throwing a EGR code will also screw things up and I think will hinder it going into closed loop properly.

It is easy to remove and take the carbon out.

Just make sure you use a new gasket when reinstalling it.