Question:

 

My 2000 Chevy Blazer has the 4.3L V6 and it will not 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 starter/charging system related. If you mean the engine cranks over but won't start, it 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 a bunch of other stuff like a bad ignition coil, fuel pump or the injector assembly, to name a few.

 

The 4.3-liter uses a Central Sequential Fuel Injection (CSFI) system which is a fuel regulator, injectors and pipes leading to poppet valves at each cylinder, all-in-one. This system has had a few issues; one is a rough running condition due to the poppet valves getting stuck open or closed.

 

There is an injector cleaning procedure which can correct the problem, but not always. That's why GM recommends a conversation kit if you're back for a second visit with the same poppet valve problem. The kit will convert the system from Central Sequential Fuel Injection (CSFI) to Multiport Fuel Injection (MFI), basically eliminating the troublesome poppet valves and going back to the standard practice of injectors located at each cylinder.

 

This may not be the specific cause of your cold start condition, but it may be relevant, so I thought I'd fill you in.

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