94 s10 blazer will not start/run

Its got the vortec....
Riding down my friends driveway it suddenly cuts off.
Changed spark plugs last night, thought that might have had something to do with it, had the distributor cap and rotor off when i did that, so we checked spark first - it was good.
Fuel pressure is 60 on cranking and stays constant about 58 after you let off the starter. From what I've read it should be higher, but I would think it would still run even if a little low.
Sprayed ether in intake and the engine caught, but will not run.
Some washing on the regulator side of the plenum, but I imagine that has been that way for a while and does not affect this problem.

During the course of trying to fix the problem, the engine caught on its own maybe twice, and didn't stay running more than a second or two.

Any thoughts?

Are you getting good hot blue spark to all spark plugs.
Have a look inside dist cap for cracks or moisture and make sure rotor is turning good.
Any side play in dist shaft?

MT,
Good spark on all plugs, no translational play in distributor. Does have some amount of rotational play.

Got to the truck tonight to fiddle some more, and decided to crank it. Started right up and ran about as long as it did last night, then just cut off. Fuel pressure stayed constant, and then jumped back to 60 when it died.

No leak down in fuel pressure. All connections and wires and hoses look to be connected everywhere. Started on starting fluid again tonight.

Took plenum off to check injector firing. First attempts showed no fuel being fired. After wiggling the connection, fuel started squirting when turning the motor over. Thought it might be a bad connection, cleaned it up and tightened the connector bands inside the plug on top of the injector. Put plenum back on and hooked everything back up. Ran for about thirty seconds and died just like the other times.

Seems like a problem in whatever is regulating the injector. Computer problem maybe? Can the regulator itself play a role in this?

Thanks for the input.

Double check for good spark at the time it quits.
THE COMPUTER CONTROLS INJECTOR PULSE.
Check for lose of injector pulse at the time it quits.
Make sure injector pulse is getting to the two wires into intake and check the intake injector wiring from intake to injector.
I have saw lose wiring or bad wiring there.
Give the pcm the old tap twist tap.
And see if it changes anything.

Any codes?
A good scanner would help to watch for injector pulse and sensor read out.

At the times it quits are the spark plugs wet on the end?

Injector does not pulse when it quits, but have good spark.
Took it to a mechanic, after running the scanner and testing some of the sensors and wires around the injector, said the ECM was bad.

I called the parts department of the dealer today, said the ECM for my VIN number was 16197427. I finally get the ECM out and look at it, the part number for the one in my car is 16196395.
Before I got it, the previous owners had the computer replaced at the dealer. Either I got told the wrong thing today, the dealer previously put the wrong ECM in, or they are interchangeable. I always felt like the Blazer didn't run quite like it was supposed to, so I assumed I was told right today. Upon a little bit of looking online, the -6395 appeared to be for the TBI engines. The -7427 appeared to be for the CPI.
Well, armed with this knowledge I went into ORiellys and got the 7427, which is not the one that I just removed from the truck.

Plugged it in and cranked the motor. Caught and ran a few seconds and cut right back off just like it has the past couple nights. Only difference this time is that the service engine soon light was on tonight while it was running, not previously.

Basically, I don't know anything about these computers, did I screw something up putting the other computer in?

The dealer should be able to decode your VIN no and get bthe right PCM no.
Have them double check it.
Also what did you do on the prom.
Did you use the old one from your old pcm.
When switching pcm no you may have to get the correct prom for it.
Did your mechanic give you the prom ID.
Get the prom ID from him and post it back.

Also check the code no and post back the code no.

Have you mechanic retest it with the new pcm in it.
MT

I had a similar problem with a 94 Bravada. Turned out to be a bad injector. I could jiggle the wires inside the plenum, put it back together and it would run for a bit then stop. Started out as a intermitent hard/no start and progressed into just plain no start.

I switched PROMs from the old computer to the new one. The GM dealer told me that the 4727 is the replacement ECM number for the one I had in it, so both ECMs should be interchangeable. Mechanic ran the scanner on it this morning after I changed ECMs. Said he was no longer getting any indication the ECM was bad, but it did indicate the injector was bad. So I just put a new injector in it.
Put it back together and it cranked up. Ran about five minutes and died again. I noticed a few things while it was running. Service engine soon light was on the whole time, I figured the new computer was just adjusting. Jumpered the diagnostic port after it died and it gave me a code 42. Bad ignition module? I will try to check that later.
Also, if i gave it some gas, I noticed my speedometer moved. I was going 10 mph sitting in the parking lot for a while there.

Could an ignition module provide spark but manage to screw up a computer at the same time?

Clear codes and if code 42 comes back go threw the repair flow chart for code 42.
Code 42 is ign control code.
Can be open or short wiring or bypass or ign module or even a bad new ECM
MT

Unhooked the battery for a couple minutes to clear the codes. Still came back with a 42. I have no idea as to the repair flow chart. I was thinking of pulling the module off and testing it somehow. I left it sitting for a few hours before I went to unhook the battery. Before I unhooked it, I cranked it and it started right up. Ran about two seconds and died.

On a side note, when I put the new ECM in, I just plugged it in and left it sitting in the floor. Is that alright or should I have put it back in its brackets. I'm thinking of how it's grounded.

Would a bad ignition module still allow the plugs to spark, but tell the engine they aren't, explaining the lack of injector pulsing?

Anyway, I appreciate the help MT, I'm kinda lost on this stuff.

You are welcome.
May not be the ign module.
But other than throwing parts at it you need to go threw the repair flow chart for that code.

Repair flow charts and good repair information can be found in a factory service repair manual or.
http://www.alldata.com/products/diy/index.html

Good Luck
MT

After replacing the ECM, CPI injector, and ingnition module, the blazer is back to running normally. Normally, that is, with its occasional misfire, cause unknown. After four days of not running, I'll take it. I think the culprit was the ignition module, but I never saw that code until the computer and injector were replaced.

Thanks for the help.

You are welcome and thanks for posting back how it went.
Glad to hear you got it going.
MT