I have a 93 .5.7 When cold mine runs great.(mine is throttle body) after it heats up it
stalls out . floods wont start unless you hold throttle open. then it
sputters for a few miles and quits. I have replaced
plugs,wires,cap,router button,coil and o2 censor. Now what? Please
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Re: 93 chevy 5.7Flooding,running rich
I want you to get OBD trouble codes from your computer. then post them on here. im sure it will hold clues to what the problem is...Various auto part stores will do this service for free in hopes you will buy parts from them...but call them first and make sure. parts to look at Idle Air Control (IAC) Valve...it acts like a choke with modern engines. also the Coolant temp sensor is associated with this as well. Second is the Mass Air Flow (MAF) Sensor. and last one is your Manifold Absolute Pressure (MAP) Sensor . lastly it could be the Throttle position sensor (TPS).. all these can be detected on your computer within the car. although the the numbered codes will be labeled with abreviations like MAP Sensor or IAC valve. also you can manually test all these sensors at home with a regular voltage tester and reading some online info...just search " How to test a MAP sensor" almost all sensors have very similar readings from car to car, so its pretty generic. hope this helps
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Check the throttle plate for varnish or carbon build up , clean with throttle plate cleaner . Have engine sensors scanned with a scan tool ,mass air flow sensor may be dirty . I'd tell you to check fuel trims with scan tool but you are probably not familiar with these . They show how much fuel the engine computer is adding or subtracting . Great diagnostic tool for trouble shooting engine running problems . Also a scan tool is great to check O2 sensor switching rich to lean an back to rich signal . The engine runs in open loop when cold which means the PCM doesn't look at O2 sensor data till warmed up . PCM/ECM adds more fuel till warmed . Then it will go into closed loop fuel control , the PCM/ECM watches O2 sensors . May have a vacuum leak ,check with can spray carburetor cleaner ,spray around the intake manifold an listen for the engine RPM to pick up or may even stall the engine. Understanding Short Term and Long Term Fuel Trim
Check coolant temp sensor. These fail often and cause all kinds of mystery problems. This unit acts much like a choke on old carb engines and can fail in different ways. Most common (I think) they fail such that the ECU thinks the engine is cold when it has begun to warm and thus the ECU delivers too long a pulse to the injectors so that the engine runs way too rich. I think it is also possible for the sensor to fail at any point between cold and warm such that the fuel mix is wrong except for the particular temp at which the sensor is stuck. Also O2 sensor has some fuel "trim" input.
Does it seem like when the engine is cold it runs ok, then when it reaches operating temp. it starts acting up? (poor acceleration, stalling) When I had that problem w/ my 93 K1500, it ended up being my oxygen sensor. (causing too rich of a mixture in the throttle body)
Hope this helps, Good luck
You may have two different problems. The rich mixture could be several things including a faulty O2 sensor or leaking injector. If a sensor fails it should set a code in the computer. The stalling could be a dirty throttle body or a problem with the idle speed control valve.
You need to change your ECTS and it's connector if it has gunk and corrosion in it. Change the ECTS to the brass tipped one and get rid of the plastic tipped one in the car.
Also change your Thermostat which is located inside the lower radiator hose on the engine block. Sounds like your car is running itself rich because it thinks it is cold and flooding itself (hence the full throttle which is a "clear flood mode" and shuts off the injectors while starting).
The injector assembly also contains the pressure regulator. Since the truck has been sitting, you may have some corrosion in the regulator and the injectors. Try a fuel cleaner and the work on the regulator.