I have a 1994 Chevy Blazer 4wd Vin W 4.3 that is stalling immediately after it starts. I'll provide as many details as possible, hopefully someone can help. I love this truck and really want to get her running again.

This all started because the truck would run until it got hot and then it would stall.

It was loosing coolant and the oil started to look milky so decided to replace the head gasket.

Took the engine down to to the block and took the cylinder heads to a machine shop where they milled 0.005" off the head and did a valve job.
Put the engine back together and upon first attempt to start engine was no start.

Tested for spark and had spark. Sprayed ether in the intake and the engine would run until the ether was burned up.

Found an unconnected vacuum line and replaced that, and tested the ignition module at advance auto parts and it tested bad. Replaced the ignition module. After doing this the truck will start but shuts off immediately unless the throttle is pushed the slightest bit.

I tested fuel pressure it was between 50 and 60 PSI and did not drop. Tested vacuum and system held 29 Inches of vacuum and did not drop. Replaced the nut kit and the spider injector and still having the same issue of start and immediately stall unless throttle is applied. Also tried new TPS and that did not change anything.

After replacing spider assembly with no avail set Cylinder 1 to Top Dead Center by turning engine clockwise til at TDC on the compression stroke. Rotor is pointing at #1 spark plug plus or minus just a few degrees. Have not gone any futher.

Desperately need some advice...

 

well, starting cold it shuts off after 2 seconds. after holding throttle down tiny bit to keep it running for a while, if i let off it will run for about double the time, 5-6 seconds. tried with gas cap off.

anyone have any ideas?

 

Maybe a faulty coolant sensor or map sensor?

edit; could be a really butthurt egr valve too

 

going to try new plugs and wires and CTS... could it need to relearn idle?

 

I wouldn't really recommend just throwing parts at it until you get the right thing unless you have a lot of money to spend. If your plugs and wires haven't been changed in a long time then I don't see the harm in it. I just put new plugs, wires, distributor cap and rotor, and new ignition coil on mine and I found it to be worth it. Take the dizzy cap off and check for corrosion or failure points, but I'm assuming you've done that already given the last sentence of your original post.

Changing spark plug 3 is kind of a pain in the ***. Easiest way to do it is to go through the wheel well. Turn your wheels towards the passenger side as far as you can to give yourself some room and there should be an access flap or something along those lines. You'll need a long extension and a universal joint for your socket to get the right angle on it. You don't wanna break it off in the block. Make sure to put some anti-sieze on the new ones before you put them in as well. Can't go wrong with NGK iridiums.

I honestly can't say for sure what would be causing your specific problem without being there to fool around with it myself. Check the EGR valve and paths under the intake plenum and clean them with some carb cleaner if needed. If you don't wanna take the intake plenum off if you put a new gasket under there, that's fine. Hopefully you noticed and cleaned the paths, if not, the egr valve is still more important to check. It's free and one thing you can check off your list. Clean the throttle body too. Take the idle air control valve out and check for failure. I'd test it with a multimeter before buying a new one because they're in the $50-80 range even on rock auto. That could be causing your problem as well. I can't say for sure if it needs to relearn idle but check the things I listed above and see where your bearings are, so to speak.

Oh and when you're putting in a new coolant temp sensor keep in mind that coolant will pour out like crazy when you take the old one out so have the new one in position to go in ASAP.

 

Assuming you have a 1994 Chevrolet BLAZER the VIN W would have MFI or the "spider" injection.
Not familiar with that car as I own a VIN Z with the TBI but have the manual.

The driveability + diagnostic manual for the 1994 S/T Trucks says:

Check engine coolant temp sensor and intake air temp sensor. (misreading can lead to lean condition when cold). Would start hard but die right away until warm.
TPS (you have that one ruled out) Closed throttle should indicate less than .85 volt.
MAP sensor.
Fuel pump operation (should run for 2 seconds after ignition to ON)
Fuel pressure (you have that one covered)
Water in the fuel?
Injector driver circuit. Disconnect all injector harnesses and use a test light and check while cranking.
Then ignition system. (should have that one covered.)
When removing the spark plugs have a good look at them and note the order from where they have been removed for further troubleshooting.

EGR (vacuum activated) may be tested closed by removing the vacuum hose and plugging the hose as not to create a vacuum leak. Then try starting.

 

Pretty sure his EGR valve will be electronic with the W vin. Mine is.

 

Yup!