hello:
I am having some strange starting problems with my 2002 Blazer LS. Blazer usually starts immediately runs fine and there is no problem, but about once a month it won't start and I have to crank it for about 15-20 min I can get it started. I do the key cycle things and it doesn't work. This model year Blazer does not have EGR. There are no codes. Don't know what the problem is. What problem could it be that wouldn't trigger any codes?

Also, maybe related maybe not, when I fill up with gas blazer runs rough while filling and nearly stalls out. Never did this before. Don't know why it would do this.

This blazer has had a lot of parts replaced
Relevant list:
Fuel pump
plugs, wires, distributor cap
Evap valve
Battery
O2 sensors
intake gasket

Anyone have any Ideas? Again No Codes

 

What’s the weather conditions when it doesn’t start?

 

It began in July and now just happened mid November. No you think it is humidity related?

 

Did these symptoms happen before the fuel pump was replaced? What brand fuel pump?

When this long cranking takes place, hopefully you can attach a fuel pressure gauge to the schrader valve and see what kind of fuel pressure you have?

My first guess is if its an aftermarket fuel pump (not, AC Delco or Delphi) it could be the culprit. There are tons of threads regarding how crappy the aftermarket fuel pumps are.

Anyway, I would start with the fuel delivery system.

Also, don't know why you are filling the tank with gas while the Blazer is running.

 

I’m an old mechanic, so we learned how to diagnose way before “codes”. Start with the simplest things first. Have you upgraded to an aftermarket distributor? If not, have you “de-screened” your OEM unit? Was it raining the night before it wouldn’t start? High dew point?
It is very common for condensation to collect inside the cap overnight in those conditions with resultant “no start” or “hard start” in the morning.
This of course is only one example of a number of things that could be causing your start issues. But think for a minute, if it was a bad fuel pump, it would do it all the time and not just once and a while. Use your head and think about it, I’m sure you’ll figure out what’s wrong

 

fuel pump was replaced by and experienced mechanic friend of mine, he usually used carquest parts and i think that is what he put in. I worked good for 3 years now, this problem just started happening in the last few months. I'll get a fuel pressure gauge handy for the next time it happens. Also I feel that the fuel pump is good, I can hear it running when i turn the key and I can smell the fuel build up in the intake when it doesn't want to start.

I fill up with the car running all the time we have a long winter climate where I live.

 

I replaced the distributor, wires and plugs myself and I always buy what I think are best quality parts I can get at the store. The distributor is a Duralast Gold and its about 4 years old now. I have seen on this forum that you should always use an AC delco Distributor.

Even my mechanic friend is stumped of what it could be, he suggested it might be a faulty crank sensor, but I don't know.

 

Check for spark and fuel pressure during the no start - Just because pump is running does not mean it has pressure.
AND when you have vapors ignite because the vehicle is running and you burn the blazer and the fuel station to the ground I guess you be warm, both while it burns and during your hospital stay in the burn ward .....

 

An easy way to eliminate one thing is a replacement of cap and rotor, use only Acdelco, these engines are finicky that way.
Beyond that, try to think of things that can go intermittent, ie: a bad pump ground on the frame, ignition switch, other electrical gremlins on either the primary or secondary ignition.
An easy way to see if it’s fuel related is to spray a shot of ether in the intake when it doesn’t start. If it doesn’t fire, you’ll know for sure which direction to search further

 

I'm going to replace the distributor and cap any the temp sensor to start, probably the crank sensor also. I have a small oil leak where the oil pan and timing chain cover meet and the crank sensor is drenched. Might replace the coil and module as well as the part are probably cheap enough and it easy to get too.
one possible problem I am afraid of is if it is the spider leaking into the intake and flooding to motor at start, this is a more involved fix and more expensive.