I didn't notice the year of your Blazer, but the bold text above may be the problem. It used to be that depressing the gas pedal was required to set the choke and prime the engine. This is not required on a fuel injected engine. Try starting the vehicle without depressing the gas pedal.

 

I learned all sorts of things watching the Red Green Show and Mythbusters.

 

Will give that one a whirl...I just hate getting shock by them there wires...I'm one of those kind of people that draws it to them...I spark just fine! hahahahahaha...Plus by reading the post and other posts I'm starting to lean toward the spark situation also..Will let you know..they just call me sparkie!! hahahahahaha.

 

Its a 2000 LT 4x4 4.3 with 105K on it. I have tried not putting my foot on the gas pedal. (It use to work that way) But, now I have to use the old carb way to get it 1st started, then after that, everything is okay for the day, go out and turn the key and she will start right up. Its just that overnight sitting that does it. Can't get to it right now, Holidays and Va appointments have fill my sheet for a couple of weeks...

Thanks for the advice.

 

FYI: Note the poster says "Then I go to 'like a carb..' routine. So I assume he knows the right way to do it.
Normal ops is
dont touch pedal.

Hard start paradigm is 'do it like a carb'
Which is:
Suspect flooding - pedal to floor and hold
to feed more fuel - pump accel a few times


What's missing is what happens if you try several prime cycles before cranking.

ALso... it COULD be an ignition problem but if it is, will usually be much worse if overnight humidity is high or raining and there's condensation under the hood. If it doesnt matter then it is probably fuel related.

 

I have a 95 same problem at first did all wires plugs cap and rotor...turned out to be my fuel prssure regulator...but wont start now without starting fluid....but only getting 35psi of fuel...so regulator worked but also had a bad fuel pump...

I also put a cam sensor in it and helped

 

Considering I have 30+ years of experience under my belt as an ASE certified mechanic (specializing in tune up among other fields) I learned a long time ago to never ***/u/me anything. With the limited amount of info given by the OP - and the fact that the problem only occurs during cold start - the first logical step in diagnosis would be to determine and verify how they were attempting to start the vehicle. You would be surprised by the amount of cold start complaints that are resolved simply by instructing the owner how to properly start their vehicle.

The problem with a paradigm is that they are open to interpretation, their meanings constantly change and they are usually manipulated to fit a particular persons agenda when they don't have a definitive answer.

When was the last time the fuel filter was replaced?

 

You're not helping here, considering the last few posts.
Which is it.. do you have to start it by pumping or flooring the pedal?
That mattered on a carb hard start, it matters here!

 

Maybe I have phase a few things incorrectly so let me start it over. 1st I am the 2nd owner of this Blazer. Bought it in 2002 and its a 2000 LT 4x4 4.3 105K. I have Never had to pump, put to the floor or any things else using the old carb starting, I just hit the key and she would start up until awhile back when she started to give me problems with starting. Is what I do NOW is turn the key wait a few seconds for fuel pump to kick, then turn the key, it cranks but no start. I release the key, then turn the key again with the gas pedal 1/2 the way down, again no start, but, it sounds like it wants to. The tach jumps to 500. Release key. Repeat the second procedure again and again and again, then I push the gas pedal all the way to the floor. Then I try to start it again, 80% of the time it will fire up, if not I just keep going at it until it does. But, sometimes when it fires up, it chugs a bit then runs fine, other times it fires as soon as I turn the key. Once I have started it for the day, it will start just fine all day long with just turning the key. It when I let it sit overnight does it give me the hard to start situation.

I also (AND it did help) replace the plugs I had just put in with the old plugs that had 50K on them. The difference was the new plugs were a hotter plug AC Delco with the last two digits of 93 on them, I put back in the AC Delco plugs with a last two digits of 92 on them and it has made it a little easier to start. The new plugs had only around 2K on them and they were wet with gas when I pull out the one plug you can get to with ease from above (Drivers side plug first one coming down the line from the front of the engine). I can get to the other side (Same position, just the other side of the engine) but its a little harder. Other wise I pull the tires off and come through the wheel well to get to the other plugs.

Now I don't have 30 yrs as a Master Mech, but rather 40 yrs as a back yard mech and I know my truck after 10 yrs. I know there must be spark and gas in order to run. I'm not all hip up on these modern vech that much. (Just bought a 2011 Nox LTZ and there is no way will I even change the oil on it) Times have caught up with me and surpass me, thats why I'm here on this site to learn, not to be insulted or call a fool, I'm way to old for that crap. Maybe I'm not "Politcally Correct" in my situation, But I damn sure do the best I can. I have described the situation to the best I can, I have admitted not doing a pressure check and I know it needs to be done, but I damn sure know how to carb start a car, I grew up with carbs, race cars with carbs, rode Harleys with carbs and other M.C. with carbs. I don't pump the gas pedal that will flood it, I push it down, not pump.

 

Ah, fair.

Here's the thing. The hard start drill is a diagnostic tool for the driver/owner. It's not a starting method.

EFI is designed to provide the right mixture for starting under any condition provided all systems and sensors are working right.

On carbs, the first thing we did was set the choke. That isnt required, as BB said.

On almost all carb cars when I started it was with the pedal depressed slightly. That no longer does anything but provide too much air.

When there WAS something wrong with the carb or fuel system, the end was you either had a flooded condition or not enough fuel.
What is the logical sequence to find which?

So most EFI designers decided to build in two paradigms:

WOT shuts off fuel or cuts it back greatly, equiv of holding choke and throttle butterflies open.
Pumping the pedal tells the PCM to send more fuel, equivalent of the accelrator pump.

There is no algorthim for half throttle at crank. It would only work same way as carb. Less fuel through idle jets and more air through engine, though there's a question how the injector timing would be changed as it isnt designed for..

Now it makes sense if you dont know whether the engine is flooded or not getting enough fuel to start with WOT. Pumping would only ,make matters worse if, say the FPR was leaking.
So if it doesnt start after a few seconds of normal crank, stop, re-prime and go WOT.

If several seconds of WOT doesnt start it , THEN pump the pedal.

If the WOT always gets results then it's pretty certain you have too much fuel in the intake at those times it doesnt want to start hot.
From what you say, you should go directly to WOT if it doesnt want to start normally and it will start. Half throttle only delays it.
That is exactly what you would have done with a carb that had a tricky float valve problem.

If, on the other hand you have to pump, meaning call more fuel then either you have a vapor lock due to leakdown somewhere or you have a vacuum leak.