Question: My 2000 Chevy Blazer has the 4.3-liter V-6, and it won't start when the temperature outside gets below 32 degrees F. What should I check first?
Answer: If you mean the engine won't crank over, it probably needs a battery or something related to the starter or charging system. If you mean the engine cranks over but won't start, finding the problem gets more complicated and requires further testing. If you're familiar with some basic procedures, check for spark and fuel pressure while the engine is cranking--cold--and failing to start. After that, you need a scan tool to check for diagnostic trouble codes and evaluate specific electronic data coming out of the Powertrain Control Module (PCM). It could be a faulty coolant temperature sensor supplying inaccurate information, which can hamper a good cold start, or other possibilities like a bad ignition coil, fuel pump, or the injector assembly, to name a few. The 4.3-liter uses Central Sequential Fuel Injection (CSFI), an all-in-one system that includes a fuel regulator, injectors, and pipes leading to poppet valves at each cylinder. This system has had a few issues; one is a rough-running condition due to the poppet valves getting stuck open or closed. An injector-cleaning procedure can sometimes--but not always--correct the problem. That's why, if you return to the dealer for a second visit with the same poppet valve problem, GM recommends a conversion kit. The kit will convert the system from CSFI to Multiport Fuel Injection, basically eliminating the troublesome poppet valves and going back to the standard setup with injectors at each cylinder. This may not be the specific cause of your cold-start condition, but it may be relevant.
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