I have a 1991 blazer with the 4.3 that cranks but wont fire. It is getting fuel, spark, good compression, coil is good, new cap, rotor, plugs, wires, new battery and alternator. It was running great and literally just died on me. I'm leaning towards the computer being bad? But not sure how to tell if it is the computer or not.

Thanks!

 

Sounds like its not getting enough fuel to me. What happens when you spray starting fluid into the throttle body? will it fire then die?

 

It won't even start when you spray fluid down it and I can actually almost flood it so that's why I believe it's getting enough fuel

 

when my spider injector crapped out, i believe it was flooding the combustion chamber. to the point where it wouldn't start up until i let it sit for a period of time to dry up. just a thought. sounds like you've tackled many other possible issues.

injector was't too difficult to change. 300 dollars or so for the part. i'm sure you can find them cheaper too.

 

My 1994 Blazer 4X "W" did the same thing, but will fire with starting fluid. Changed the fuel filter (it was a pain), have fuel (can hear pump and goes to filter) and spark. Also has recent, full tune up, minus module. I'm baffled...

 

With the way the fuel systems are in these trucks, before you do anything else, do a pressure check, and post the numbers up.

Fuel pressure has to be the right amount; just because you hear the pump run, it might not be making enough pressure, or the regulator might be not holding enough pressure to fire the injector.

 

My 91 s10 with a TBI is doing the same thing, it will not start after the brakes locked up in traffic one day, approaching a red light. Avoided a wreck but it hasn't started since. It cranks, has fuel and spark. The brake light was on for a month after replacing some rusted out brake line, i couldn't bleed the lines enough and stomp on the brake pedal enough. Then on this day the light went out and two miles later they locked up.

New plugs, cap, rotor, ignition coil, alternator, fuel pump, ignition switch, and I tried a new electronic spark control module and ignition control module but that didn't do it. I'm all out of ideas, any suggestions would be appreciated.

 

I had full intention of checking the pressure last night, but O'Reilly told me they had the kit. Got there and someone else had borrowed it. Shooting for today

 

im having the same exact problem i kno its flooding because if i hold the gas to the floor and crank it it would putt and fart but wont kick and turn over... So im leaning towards the regulator on th throttle being stuck or the coolant temp sensor being crap... cause that will cause fuel to flood also...

I eliminated the fuel lines cause it started and ran after i redid them new fuel pump and sending unit new filter i took my spark light to all of the plugs they checked out so now im stuck inbetween those two things...i hope you find out your issue it might be the same im having

 

Check spark with an inductive timing light at each plug. Pour a small amount of gas in the TBI and see if it tries to start if it does than you need to check fuel pressure and verify that the injectors are firing. A Noid light can verify that the injectors are getting a pulse signal. The the timing may be off. Get the number one cylinder at TDC on the compression stroke. Mark the location of the number 1 plug wire on the somewhere where you can verify it with the cap removed. Remove the cap and see if the rotor is pointing at the number one plug location that you marked.