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2000 S10 Blazer 4.3L 2wd

Long story short.
Replaced intake manifold gaskets, after putting it back together it started and ran fine. Better than before. Drove it @20min until it warmed up. Shut off and let sit for @20min. and it won't start. It will start using starting fluid but then dies again.

I figure I have to have spark and the right timing for it to have ran as good and long as it did @ town. Maybe fuel delivery? I have fuel to the fuel line valve by the firewall. It spews gas when I push it in. The pump kicks on but I don't know the psi. Since it was running...again I don't know.

I will check the electrical connections maybe on the fuel injection unit as well as others in the morning after recharging the battery. It died trying to start it.

If it starts with starting fluid that tells me it is not getting fuel but I don't know why. Any ideas? Your help is certainly appreciated.

 

My 98 did this and it was the spider. But you should do a leakdown test

 

Suggest checking the large electrical connector on top of the air plenum; look at the pins, make sure none are bent, and the connector is completely mated.

Next would be to rent/borrow fuel pressure gauge and check fuel pump pressure.

Good luck.

 

The injectors need a minimum psi to open. Do a fuel pressure/leakdown test.

 

The injectors should pulse while cranking and running regardless of fuel pressure. If the pressure is below 60psi, you'll probably need to add carb spray to get the engine running, (starting fluid is not recommended). If the pressure drops below ~43psi, the poppet valves, (at the intake ports) will not open and squirt the fuel.

When the ignition is initially turned to the RUN position, the fuel pump should run for ~2 seconds and then shut off. Fuel pressure must be checked during this 2 second time frame while the pump is running and the engine is off. Fuel pressure must be 60psi to 66psi, and it must remain above 55psi for at least 10 minutes after the pump shuts off. If it fails one or both parts of the test, there is a problem with fuel delivery and further diagnosis is necessary to determine if the problem is in the fuel tank or in the plenum. Post your results.

 

Thanks for all the advice so far. I will try each suggestion until I figure it out.
Update- This morning after charging the battery and before reading your replies I tried to start it again(using starting fluid) but I'll nix that now and use a squirt can of gas instead.
Anyway, it started ran smooth for about 2 sec. and died. I tried it again and it started, again ran smooth for @ 2sec. then acted like it was going to die and then revved back up on its own. It ran on its own for about 30 seconds total but during that time it would continue to rev up to @2500rpm, idle back down and drop down like it was going to die for @2sec. Then it would rev back up and continue this process off and on until the 30 secs. were up then died.
It will restart but not without spraying in the carb. and then same process happens.
I will check the connections for the injectors on the plenum and see about acquiring a fuel pressure gauge next.

 

Sure sounds like a fuel delivery problem, (low fuel pressure). Most auto parts stores rent/loan/sell fuel pressure testers. This is an entry level one that works well: ActronŽ

 

I borrowed a fuel pressure gauge from O'Reillys.

1st cycle of key the fuel pressure went to 5psi.

2nd cycle- 15 psi

3rd cycle- 30psi

4th cycle- 50psi

5 cycle- 60psi.

Now from I understand it should immediately pressure up to @60psi. Right? Also I have to mention when I tried to start the blazer it ran as I mentioned before but maintained 52-55psi before dying. Should it stay running maintaining that much pressure?

BTW- I never heard the fuel pump kick on...at all. Even though I have heard it kick on earlier today. Strange it would be intermittently. I figured once it stopped working that is it.

Also I checked the connections (pins) on the Central Sequential Fuel Injection connector. They are all good.

And I heard the injectors engage like they were trying to work. Even though I was really careful and took my time cleaning everything before opening up the intake as to not get any dirt in anything if there was, by chance, particles of dirt get into the injectors would that cause this issue as well. Wait. If it will start under its own power after cycling the fuel pump and it starts to run smooth before dying than the injectors should be ok...I would hope.

I guess that puts me back to the fuel pump as you have mentioned. It is just strange it ran fine before and after...for 20 min...and then just quits.

Am I looking at having to pull the fuel tank to change the pump out now?

 

When the pressure tester is initially connected, there is air in the lines and tester that needs to be bled out before an accurate reading can be taken. This can sometimes take a few cycles of the ignition. A more accurate way to test, on your 2000, is as follows:

In the underhood fuse panel there is a single, vacant terminal just forward of the fuel pump relay. Connect a jumper wire from battery positive to the vacant terminal and check fuel pressure while the jumper is connected.



After the pressure tester stabilizes, note the pressure reading. Then disconnect the jumper wire, wait 10 minutes and take another reading. Post both of the readings.

 

Will do Mr. Captain Hook.