I have some problem with my 99 Blazer 4,3, when it gets to freezing point it wont start, it seems like there is no spark at all but if I use a heater it starts right away, or if its a little bit over freezing it also starts.
What can be the problem here, any ideas?

 

Does it crank but not start?

To what heater are you referring? The block heater?

To start you need air, fuel and spark. There are threads here that cover how to check the fuel and spark systems.

 

Year, it granska but it feels totally dead.
I used än electrical engine heater, not sure what you actually call them.

I was wondering if there is some common problem like with the distributor or so?

 

Does the engine crank faster when not as cold and also is more likely to start?

If it is only cranking slowing, perhaps you need a new battery?

The chemical reactions that are responsible for providing the voltage and current are less efficient at colder temperatures. A battery on its last leg can work sufficiently well at a higher temperature but can easily be insufficient at a lower temperature. A new battery must be at a very low temperature (below what most of us would ever experience) for it to fail due to temperature.

Note that it is not just the voltage but also the battery's ability to output current to drive the starter that is needs to be sufficient.

A couple of many useful links that explain how battery performance is reduced in cold weather and how there is more asked of a battery when it is cold.
Pacific Power Batteries - About Automotive Batteries
The Effects Of Heat And Cold On Car Batteries | Scott's Fort Collins Auto

BTW I have a 120V factory installed block-heater on my mine that is installed in one of the freeze plugs in the block in order to heat the water.

 

Thanks but the battery is fine and it cranks at a good speed, the ignition simply does not respond, but as soon as it gets over freezing it ignites.
What on earth could have that effect, some temp sensor that controls the fuel? Moisture in distributor? Fuel filter freezing?

 

Wow, if the battery is good, you do have a strange problem.

I'd check to see if the spark is good when it is not starting and also check the fuel pressure also.

There will be instructions on the forum but also elsewhere online to help you with that.

Good luck and keep us posted.

 

It's not a strange problem have run into this several times.
If like most it will have two temp sensors one for the gauge and one for the computer, usually the one for the computer is throwing a false reading, It may or not throw a code but you might try changing it out

 

Is it correct that you can reproduce the issue nearly any time consistently?
If so the troubleshooting should be easy enough.

Temp sensors should not de-energize the ignition but would have an impact on injection quantity when cranking and starting.

Having no spark when cold could indicate a problem with the ignition module.
Bad solder points do this sometimes, as would broken wires or an internal (soldering or connector problem) in the ignition module. Coils could also be the culprit.

OBD Scantool - what do the various sensors show when not cranking, just with battery "ON".
You should be able to see the temp sensors and compare what you see to the actual temp of the block.
When cranking check for RPM signal.

To go further a service manual including the electrical and diagnostics is required. Then you can measure the sensors and coil for voltages.

I'd suggest to invest the 150$ in the OEM service manuals (reprints on rockauto or second-hand on ebay), instead of parts.

 

Thanks! Where is this sensor located, any idé?

 

I didn't say the temp sensor had anything to do with the spark just the no start condition in cold temps.
Very first post was it SEEMS to have no spark so reading between the lines I figured he didn't know for sure just acts that way by the way it spins over with no hint of starting.
On my 4.3 the sensor for the computer is located by the thermostat and the gauge sensor is located in the riders side head along with a knock sensor in the drivers side head