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My 4.3 vortec engine in my s10 blazer won't start unless throttle body spray is used. Already replaced the fuel filter, fuel pump, fuel injector, fuel regulator, and the computer.
I wonder if that was his problem? Could the ignition module be intermittent? I have the same problem but my 4.3 will start about 45 minutes later if I let it sit.I wonder if that was his problem? Could the ignition module be intermittent? I have the same problem but my 4.3 will start about 45 minutes later if I let it sit.
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The Vortec 4.3 liter V6 is notorious for problems with the fuel injector.One injector solenoid feeds all 6 injector nozzles,and sometimes one whole side of the engine will not get any fuel.See if you can smooth out the engine by spraying some starting fluid into the throttle body(remove the rubber hose from the throttle body).If this doesn't seem to make a difference,you may just be dealing with an ignition problem(cap/rotor/wires/carbon tracks on the spark plug insulators).
I don't know it sounds like you went over this thing pretty good . You did the fuel filter i had to ask but it sounds like a fuel delivery problem . Your fuel pressure is on the money if the thing was brand new . the olny thing i can think of that would make sense is were did you measure the fuel pressure . To make sure that its getting to the throttle body you need to check it there . If you have good flow there the pressure regulater or the injectors them self . Pull your plugs out if some of them look white that means its running leak on those cylinders . This will give you a lot of information for not a lot of work . I have persinaly have a 96 4.3 vortec 4x4 so i know this engine although yours is the OBD 1 system there still vary similar . Let me ask you this how dose the engine run when your not going up hills ? Get back to me [email protected]
The regulator is built into the throttle body. Recommend you crack loose the fuel inlet nut on the throttle body to see if fuel is getting there. If yes, the next question would be, are the injector solenoids clicking? If you can, put a long screwdriver on the solenoid and hold it to your ear while someone cranks the engine. If it's clicking, rebuild the throttle body. If not, use a meter or scope to check the signal to the injector. If there is a signal, replace the injector. If no signal, suspect ECM or one of it's input sensors. These sensors would normally set the engine light if the ECM is not getting a useful signal from them. If you have more questions, please let me know.
leaky injector/s is flooding motor, mechanically clean or replace. And clean throttle body while you are at it with spray cleaner. Should be almost spotless where large throttle valve opens and closes.
Try replacing the fuel filter, but it sounds like you have a weak fuel pump. Your cold start pressure should be 62-65 psi and drop about 5 psi when the engine is running. Anything less then 62 psi is going to cause you to have starting issues, you can also test your fuel pump by blocking off the return line to see if you get 75-78 PSI. this is just a test to see if your fuel pump is still good. If you have less then that with the return line blocked off, replace your fuel pump but check your ground wire first. The ground wire is separate from the wire harness and grounded to the frame and a bad ground will give you a weak pump.
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your statement is fuel pump work ok, have you tested for proper fuel pressure. just because the fuel pump works it could have less pressure needed to start the engine. maybe the fuel filter is plugged. start out by replacing the fuel filter, if this doesn't fix it, you need to pressure test the pump. even 10 psi reduction in pressure will allow the engine not to start.
You need to check and make sure you have fuel pressure, then check for spark at ignition, if those check out then check for pulse width at the injectors. That basically is the electrical signal which tells injectors to spray fuel. Use what is called a Noid light on injector pulse width check. that will eliminate all possibilities other than internal issues with engine. I.E. broken cam, broken timing components, obviously if all I mentioned checks out then run compression test. Good Luck
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