Ok i have a 97 chevy blazer with 190k. Every once in a while it starts prefect but most of the time it cranks for 5-10 seconds. checked the fuel pump it was bad and replaced it. week later did it agian had the spider checked told it was bad and replaced. week later again its killing me.
here is a list of what i have replaced.
fuel pump, fuel filter, fuel tank, spider injector, coil, plugs, cap, rotor, wires, cleaned the mass air, and crank position sensor. also had checked map and tps both within spec.

p.s. also she stumbles on take off but after that she got tons of power

 

During the 5-10 second crank time, have you checked fuel pressure and spark? What brand fuel pump did you install? If you installed an aftermarket fuel pump, lasting a week is not surprising.

 

I had a similar problem with my '01. After driving and getting hot I would park for 20-30 minutes (lunch break) and it would crank for a long time before firing. Replaced fuel pressure regulator behind spider and problem went away. Also replaced intake manifold gaskets (Coolant and possible vacuum leak) at the same time. See if that helps.

 

fuel pump is at 65 psi on start and 60 at idle used a delphi unit and i have spark.
and the new spider came with a new reg. so this is why im lost.

oops forgot the shims on the crank sensor i will try tonight and reply
glued to the bottom of the box.

 

Not to hi jack this thread but I'm having the same issue. I have replaced the fuel pump (DELPHI) twice. Fuel filter twice, plugs, cap rotor all oem parts. That is where I was headed next was to update the SCPI with the newer MPI used from 02 up.
Mine isn't as bad if I loosen the fuel cap. I'm also waiting until I get to my mechanic who worked for a Chevy dealer & knows these Blazers well. It drove me crazy also so I'm just crazy with out much hope of recovery.

 

ok this might sound stupid but i know that i cant just start my truck right away otherwise it has to kinda work..i have to hold the key untill the fuel pump is fully primed (until the humming quits) then i can start it ...my buddy has an s10 pick that does the same thing also my little bros s10 he has to do the same we have all changed pumps atleast once

 

Im not going crazy just loosing my hair lol.
So added the shims and the same as before. Now that its below 90 degrees during the day she runs
fine just barely notice if at all im stumped. MAP wouldn't that have thrown a code.

 

Did the replacement pumps come with a new vehicle side electrical connector? And have you gone over the ground for the pump? What I am thinking is that the pump may not be getting full battery voltage (either through poor connections at the main connector or a port ground) during initial start up.

 

it did come with a new pig tail just like the last pump. The truck just has to last 4 more years so she can get a new/newer chevy. i'll check the ground i dont remember if i had power or not.

 

I work in a shop where we had same type of problem with 95 blazer. replaced fuel pump several times did all kinds of testing on intermittent prolem. when testing electrical make sure battery is at least 75% charged. 11.89 volts post to post is a dead battery. as swartlkk said it turned out being ground at fuel pump. ran a redundent ground from connector to frame no more problems. we attached test wires to black(ground) and grey(pos) wires would get a veriety of readings mostly 8.97 volts then grounded neg. test lead to frame and got over 10 volts. with low voltage would get 44psi on fuel gage. once fixed got 60 psi for 2 sec. when key on.