Alright, so as the temperature has dropped over the past few weeks my blazer has become very hard to start after sitting over night, once I get it started after several tries then it works fine the rest of the day, I've been doing so much research over the last few days online and it seems like its a very common problem and usually a new coolant temp sensor fixes it, so I went and got a new one from pep boys (it was a cheap BWD brand if I remember) so I'm wondering if its possible that I may have gotten a bad one.

I also read the a malfunctioning egr valve would cause hard cold starts so I put a thin piece of metal between the egr valve and the gasket, as I read that it would fix any egr related problems (my truck seems to have gained a little bit of power by doing so and seems to run a bit better too) but my problem still exists.

Now it seems that my only other solution is the fuel pump isn't holding pressure and its actually not cold weather related but its the fact that by the time morning arrives my fuel pressure bleeds back down and it takes it a little while to get it back up to 55 psi.. but if this were the problem then couldn't I just cycle the ignition key a couple times before attempting to start to see if that fixes it? (I just thought of that while typing this lol never actually tried that..) anyways as always, All help is appreciated, I really need to get a hold of a fuel pressure gauge. any ideas?

Thanks guys, for continuing to keep my blazer on the road...

I guess the worse case scenario is that I will just have to keep a can of starting fluid handy for in the mornings. Although I would much rather fix an issue then put a band aid on it

 

Fuel pressure problems are more likely. I would get a gauge on it and make sure that it isn't bleeding off. You can also do the key cycling to prime the system.

Blocking off the EGR valve is only to be used as a diagnostic test and should not be left that way.

The only way to know if you received a bad engine coolant temperature sensor would be to test it.

 

ok, one more thing I wanted to mention Kyle, I did replace my fuel pressure regulator and installed a new nut kit when I first got the truck a couple of months ago. so if it is loosing pressure then it would have to be fuel pump related (no gas smell coming from engine either) are the pumps known for having this issue? Another thing since I don't have a gauge I could just use a nail or something to push down on the valve stem on the fuel rail (I think I should be able to tell by how much pressure it shoots out if its really low or not right?)

I really didn't want to drop the tank in the middle of winter!!! lol

 

The check valve in the pump can go bad.

There is no way you can accurately tell the difference between 52psi and 55psi by manually opening the pressure test port nor is there a way to monitor leak down using that "method".

 

good point, one more question, It seems like I remember reading that when you buy the fuel pump for this model you have to buy the whole assembly with the sender and wire harness and what not, but when I was looking on the part store web sites I noticed that you can buy just the (delphi pump) by its self or the entire assembly, is the pump welded on the assembly or is it possible to attach just the pump to the pre-existing unit? Its a $120 dollar difference in parts is why I'm so concerned. thanks

 

In your truck, the sending unit is metal. The pump can be swapped out somewhat easily in your case. Just get a quality AC Delco or Delphi replacement pump if that is what your diagnosis leads to.

 

Ok, I figured out what happened, back when I first got the blazer it had a hole in the fuel line going into the injector (ie nut kit) I didn't have the money for the nut kit so I went to the local junk yard and just pulled off the plastic line and replaced my leaking one with it. Well I decided to take a look inside my plenum today and sure enough that same line was leaking, not as bad as it was but enough to cause problems.. I went to part store and bought some "fuel injector clamps" and put one on, tightened it up really good and it seems to have done the trick. apparently where it has been installed so many times it wasn't a tight enough fit anymore.

 

Hopefully that holds. For all of the chasing around you did though, you probably could have replaced the lines..