Truck has been running great lately. Went to start it up today and it cranks but won't turn over. For a second after cranking the truck it will sputterbut never catch. I don't have any codes popping up on the dash ,and i do here the fuel pump coming on.The truckhas a new battery,alternator, and starter.At first i thoughtit was the starter since it's cold up here but it's cranking not ticking. I need some direction on what to check. Is this a fuel filter/pump problem? Please give me some direction i'm not sure where to start. Truck is a 99 4x4 blazer.

thanks

 

my brothers 97 s10 v6 4.3l truck would do same thing for awhile b4 the fuel pump actually stopped working all together.

try some either aka starting fluid or cap full of gas straight into the intake and then see if it starts up , if it is the fuel pump dying , it should start up and may keep running , if so then the pump cant generate the psi needed to start but can make enough to keep it running after its started ...

try that and lemme know what happens .

hope this helps ya

 

Connect a fuel pressure gauge to the schraeder valve on the fuel line on the top of the engine. Turn the key on, but don't start the motor. You have to have ~52 psi just to start the engine and the pressure should be 55-62 psi to be normal. If the readings are low, you have a bad pump or relay. Turn the key off and the pressure should not drop more than ~2-3 psi. If it drops more, then the fuel pressure regulator is bad.
Next, check the distributor cap and rotor to see if they look to be in good condition and make sure the wires are connected well. Make sure the wires are on the spark plugs tightly. Then you could pull one of the wires from a plug, put a screwdriver into the end (be sure you wear leather or rubber gloves and aren't touching metal) and hold the blade close to an engine ground while cranking the engine to see if you have a good spark.
If these simple tests show a problem let us know, or if they all check out, maybe one of us can go from that point.

 

Update: I got the truck started and was really low on gas so i filled it up and put some heat in the tank. It's been really cold so i thought maybe that was the problem.Ran fine no problems until today same thing happened. First tried spraying the intake and nothing so i'm thinking it's a spark problem. Pulled the first plug out by hand so now i'm in the process of changing plugs and cap. Will update again when i'm all finished.

 

Two weeks ago same problem chasnge plugs and oil (gas in oil) but the reason was a wear on the bushing in the distributor, change and runs fine

 

are you getting any spark might be a bad ignition coil

 

This is reaching across from a totally different platform, but I had something similar in the Z once, it would turn over just fine, but wouldn't fire for a bit, then it would fire right up some other times. It turned out to be the Crank Positioning Sensor went out.

 

Well changed plugs and cap. Started the truck and still would stumble a bit. Found a small vaccum leak, fixed that and started up without any problems. Drove the truck last night everything is fine. Today went to fire it up and again same problem as first posted. Truck doesn't want to turn over but i did manage to get it running by pumping the gas pedal a few times. This is very fustrating.

 

If the crank positioning sensor went bad, or having a bad ignition coilthrow any codes.

 

Ricky, have you tested the fuel pump as I suggested earlier?