Questioni have a 1994 s10 blazer 4.3 vortex eng with just over 100,000 miles. when the eng is cold i have to turn it over a few times before it will start. some times the only way to get it to start is to spray card cleaner in to the intake and it will start right up and run good.if the eng is warm it starts right up and runs good. if it sits for more than 5-6 hrs is is usually hard to start.the cap. rotor, wires, and plugs are less than 1 yr old.i just replaced the fuel filter, coolent temp sensor.the fuel pres. is about 55, the fuel pump relay seens to be working and the oil pres switch tested good. thanks for any advice.
AnswerThere are NUMEROUS possibilities that can cause this problem, One being that the fuel pump is NOT priming and pressurizing the fuel system prior to starting the engine.
You should be able to hear the fuel pump in the fuel tank run for 2 seconds just as you turn the ignition switch to the ON position. Listen at the gas cap opening and have a helper turn the ignition to the ON position ONLY. Do NOT crank or try and start the engine.
Does the fuel pump run for the 2 seconds ?.
With that amount of mileage I am surprised that the fuel pump has lasted this long as they usually start to get weak or quit around 50,000 miles.
It is stilll possible that the fuel pump is NOT putting out enough fuel VOLUME, Pump is running slow during the 2 second initial run period and not enough fuel is being delivered into the fuel system.
You may have a faulty or sticking IAC motor, A faulty ATC (air temp sensor) or the engine is worn to the point that there is insufficient compression during the STARTING process.
You may have the normal buildup of residue surrounding the throttle plate area thus causing the throttle plate NOT to be able to close all the way of which needs to be cleaned.
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