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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29586
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2001 chevy 4.3 blazer have replaced fuel pump, crank sensor.

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2001 chevy 4.3 blazer have replaced fuel pump, crank sensor. will start and run when cold after warming up will shut down only running about 75 feet. starts runs real rough and then quits.

Good morning, I am cam. With your vehicle, do you have a check engine light stays on? Will the engine remain running if you simply idle it? ? Also, have you replaced fuel filter at any time?

Customer: replied 2 years ago.
fuel filter replaced. no check engine light on. no engine will not remain running while idling.
OK, I'm not sure what you have for test tools so I'll outline what I would check if your vehicle is in my bay. I would start by monitoring the fuel pressure while the engine is running. I understand the new fuel pump and a new fuel filter been replaced, however the fuel pressure regulator could still be faulty. I would make sure the fuel pressure remains above 55 PSI as the engine stalls. After that, I would remove one of the spark plugs and monitor the spark as the engine stalls. Do we loose spark first or do we have spark throughout the stall? Next, I would try unplugging all of these sensors one at a time. Mass airflow sensor, engine coolant temperature sensor, map sensor, camshaft position sensor in the distributor. Each time I would see if these change the way it runs. If nothing changes it, then we may need to get our hands on a scan tool that will read live engine that. It may be that the computer sees something faulty as it starts to warm up and it was out of range. In the end I suspect a problem with either the engine coolant temperature sensor, the crankshaft position sensor under the harmonic balancer or possibly even an ignition coil or ground issue. If you do not have a scan tool that will read data, there is a cost-effective alternative. Lemar monitors makes a device that allows you to connect your smart phone to the vehicle. It's about 100$.
Customer: replied 2 years ago.
all of your suggestions have been tried. mass air flow sensor code keeps coming up. new mass air flow sensor has been put on as well.
What exact code number is *****?
Customer: replied 2 years ago.
put an old mass air flow sensor on and now the vehicle runs without stalling. so obviously the new mass air flow sensor is bad. the code is PO101.
That code refers to the amount of air passing through the sensor, specifically it is a mass airflow performance code. With the old sensor, are the issues fully resolved? That code will also set if the exhaust is plugged up.
Customer: replied 2 years ago.
issues resolved ty
Thank you for allowing me to assist you. Please rate my answer 3-5 and feel free to ask any follow up questions regarding this issue you may have. Again if you need further information, please use the Reply/Continue Conversation link to ask for more help and I would be happy to assist you further. You do not need to give a negative rating or relist the question to get more help :)
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