Cold Blazer Won't Start

My Blazer dosen't start in cold temps. I've had it to my mechanic several times and he can't find the problem. He has tried many different things (replacing sensors....etc.) But still can't get it to start (in cold weather)...It acts like its not getting any fuel...it does crank...and crank but .........I CAN HEAR THE FUEL PUMP WORKING...BUT...It does start in warmer temps ...like above 33 or so..... Now, Funny Thing I Just Figured Out A Way To Get It Started YESTERDAY. It Starts When I Just Barely Turn The Ignition Switch. (Not Turning It All The Way) It Starts In The "running" position. THIS SEEMS TO WORK BUT I'm Sure This Probably Isn't Good For The Car, Plus I Have To Tell My Family Members Ther's A Certain Way To Start The Car....has Anybody Had This Problem?

My 2000 blazer suffers from the same problem, although, the temperature range is a bit lower. Mine will not start at temperatures below +10 F. We suspect ignition switch and intend to check by heating with hair dryer and then attempting to start. Have you learned more? I will post again as we learn more.

I am having the same exact problem with my 96 S-10, 4.3L. Found that if I put key in run position until fuel pump "pressurises" the system - it fires right up...I just replaced the fuel filter, mainly for good practice, and am suspecting the regulator may be bad. I purchased a fuel pressure gage (which was only $30 at NAPA) and I have plenty of pressure when it's running, 52-54psi. BUT, after fuel pump shuts off, and the car is not running, pressure begins to bleed down to zero. At first I thought I may have a fuel leak! No leak found yet...COULD THIS BE A BAD REGULATOR???? I have not thoroughly tested the truck since replacing the filter, but I just tested it after sitting 1.5 hours in 20 degree weather and it started right up. I still don't think it's fixed....PLEASE HELP!!

You should be at 56-60 psi for start, 61-65 psi at running...

On a 96 CSFI system fuel pressure spec is 60-66 psi key on engine off

Hi Everyone. Seems to be a growing trend. I have a 2000 S-10 4.3L Blazer 4x4 and its giving me trouble on cold mornings as well. I get a spin no start sometimes and nothing others. I've been to the dealer and they replaced the fuel pump but I'm still getting problems. But I've noticed that its only on mornings that are below 32. I've tried dumping a can of gas treatment in thinking it was a frozen gas line, but still no help. The last few times I could get it started was to try cranking, waiting 2 mins, cranking waiting 5 mins, then cranking again. I'm going to have to take back to the dealer soon, anyone have any updates on this common problem?

Replaced ignigion switch. Although we haven't had -10 degree F. weather since, this morning was around + 6 degrees and truck started without a problem. We suspected switch because, even in coldest weather, 2000 Blazer would start if key was held between run and start position, but wouldn't start with key in full start position. Seemed that ignition switch was adversely affected by extreme cold. Don't fully understand but seems OK now. May not know about -10 degree weather till next year -- hopefully.

I've been researching the failure to start / fire , 4.3 Litre V6 Chevy / GMC engines when outdoor temperature drops. ( Weather somewhat below freezing. )
Most posts say it is probably due to a lack of fuel pressure during starting. Could be aging fuel filter, fuel pump, or fuel pressure regulator. I'm having that issue, my 4.3 L Astro van won't start. I'm gonna try the filter first as it's the cheapest fix. Can also borrow / rent fuel pressure gauge to check that. Partsource rents many tools for refundable deposit only = free .
2ndly sites way it can be a slightly weak battery or coil, so the ignition is consequently underpowered upon starting. ?

I am having the same exact problem with my 96 S-10, 4.3L. Found that if I put key in run position until fuel pump "pressurises" the system - it fires right up...I just replaced the fuel filter, mainly for good practice, and am suspecting the regulator may be bad. I purchased a fuel pressure gage (which was only $30 at NAPA) and I have plenty of pressure when it's running, 52-54psi. BUT, after fuel pump shuts off, and the car is not running, pressure begins to bleed down to zero. At first I thought I may have a fuel leak! No leak found yet...COULD THIS BE A BAD REGULATOR???? I have not thoroughly tested the truck since replacing the filter, but I just tested it after sitting 1.5 hours in 20 degree weather and it started right up. I still don't think it's fixed....PLEASE HELP!!

Fuel pumps have a built in pressure regulator. You can install an inline check valve or a new fuel pump.
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