No Fire When Cold

palleye · February 7, 2009

I'll try to keep this short however there have been several thing done during the process.

As stated under description I have a 2000 S10 Blazer ZR2 with a 4.3 (W) and ~105K miles. The problem is when the temperature drops to low 20's to the mid teens I loose spark. I live in Iowa so during the winter this is a problem. I will state the vehicle runs great otherwise, no codes are set, runs and idles smooth, better then original EPA gas mileage.

Due to the age and miles I've replaced: Spark Plugs, Distributor Cap, Rotor, Wire set, fuel filter & performed three stage fuel system cleaning. The fuel pressure regulator was leaking (slightly) so that was replaced. The battery was 3 1/2 years old and I had it tested, it was bad and replaced. Some where along the way when trying to diagnose the problem the tach stopped working so the ECM was replaced (hoped that was the problem). None of this fixed the cold start issue. Then I replaced Ignition Control Module and the Coil - no help.

I've noted there is a wire (yellow) off the Mass Airflow Sensor and when the engine starts there is voltage on this wire, when it will not start there is no voltage. When the connector to the MAS is pulled it starts. One question - is this normal or could this be the problem before I go and replace the MAS. If this is normal operation I'd appreciate any and all suggestions.

Dazed & Confused in Iowa

Palleye

palleye · February 16, 2009

Update: After going through the wiring noticed that during a no fire condition, when the key went from "START" position to "ON" position - i had FIRE for an instant.

Bing bang boom installed new Ignition Switch and all is WELL so far (6 days). It's been 10 - 13 degrees on two nights since repair and starts Normal, were it would have easily failed before.

Now I hope it gets cold enough to go ice fishing some more.

Happy in the Heartland!!

Palleye