I am new to the S10 blazer world (used to have a 1979 K5 Blazer) and I have done a lot of searching throughout the forum to find a solution. We had the front passenger tire blow out and then a week later the engine began to slug down and drag to a point it would start (in about a 20 mile drive). There was no warning lights coming on and no overheating indicated. Nothing was damaged under the Blazer that I can see, no fuses are blown, the oil is not milky, air bubbles to not come out of the radiator when trying to turn over. Before I start to actually tear into the engine I will perform a compression test. Is there anything else I should be looking at or checking? I am not as familiar with these engines. Thank you in advance.

 

I was just troubleshooting my blazer for a no start problem so maybe I can help a bit based on what I encountered.

Firstly I am assuming the car is cranking but not turning over, not just clicking from a dead battery or giving you nothing from a dead starter.

It seems the two first things you want to check is for
A: Fuel failing to reach the engine
B: A bad component of your ignition system.

Fuel: An easy test to see that your fuel pump is working to to have somebody listen by the rear tires when you turn the key (not to crank, just to turn the lights on) and when you turn them back off. They should be able to hear very easily the motor in the fuel pump working. If you don't hear that your fuel pump is dead or your pump relay went bad.

Second you can check for fuel pressure. A basic way is to hit the schrader valve stem and see if gasoline spurts out. Its not accurate but if you have decent pressure it will spurt out, if it does not you have a problem. You would be better using a fuel pressure gauge if you have one or you can borrow one from autozone to get a real idea if your fuel pressure is good and if you have a leak or not...though fuel leaks usually make themselves pretty apparent.

Honestly though the easiest way to see if its fuel starvation killing the engine is to shoot some starting fluid in there and see if it will catch at all. If it ignites it means your engine likely is not getting the fuel it needs, if it cranks and cranks with that in there then you need to look at the ignition system.


Ignition system:

Your main parts are the plugs, wires, distributor cap, rotor, distributor, ignition coil, and ignition control module. You want to get a spark tester, a good one that sparks from red to blue depending on the quality of the spark, and start at the plugs to test for spark. No spark at some but spark at others is bad distributor cap probably or bad wires. If you have no spark at any you work your way back to see if the coil is sparking to the distributor.

Also you can make sure the relay for the ignition system is good too by swapping it with one you know works (like if the fuel pump relay is working)

Good luck boss.