I had a 91 P/U but it was the newer body style
I remember running into an issue with the fuel pump relay on mine
After replacing the fuel pump it would still not start randomly
If I remember correctly if I cranked the engine long enough untill it developed oil pressure it by-passes the relay

 

Yes, it sounds like electrical if you don't here the warm friendly buzzing of the pump when you hit the key.

I've only had my 89 less than a year and the others I've worked on were pre-fuel injection.

Start at the fuse panel and make sure the fuse for the FP is good then head down stream with your multi-meter and start checking to see where the power is getting interrupted.

 

Your blazer looks just like mine

Well before I cut the top off, installed the suspension and various other modifications...

 

I did check my fuses first and they were all in tact. There doesn't seem to be any fuse block under the hood, guess because its old. I honestly wouldn't know what to do with a multi meter or where to check for power

 

I wanna take my top off! No pun intended

 

A multi-meter is one of the most basic and useful tools if you ever plan to work on electrical systems.

Called a multi-meter because you can take readings on all sorts of stuff. In reality you only need to use one function. You can get them pretty cheap at any auto parts store or hardware store like Home Depot or Lowes. Walmart or Fred Meyer / Kroger will have them in the hardware section too. As cheap as $19.99 sometimes... for what you're doing cheap ones are fine.

You switch the dial to the Volt section and put it on *20*. This means that it will be reading volts in the range of 0 - 20 volts. Automotive electrical systems are 12volt (really 14.2) so this is right on. You touch the black lead to any piece of metal: screw, bare dash piece, chassis. Then you touch the red lead to find voltage.

 

Ok. Checked the relay, its not the relay. My friend has offered to drop the tank and replace the fuel pump. And while we're at it we'll just do the filter too. We'll see if that works.

 

I had a friend who replaced their pump with a cheap store brand pump, regardless to say he had to do it again when the pump went out in a week. Since this is such a big job and the AC Delco pump isn't that much more money my advice would be to spend the money for the best pump you can get.
Good luck with it!

(and I hope your tank isn't full!)

 

It better not go out in a week! After all the hassle I've been going thru just to get parts and stuff. But, I'm gonna remain optimistic. For me most things go wrong actually working on the car. And there isn't much gas in there and he'll siphon it out. I was told before that the truck was running rich. I wonder if that is a contributing factor for the pump going out.

 

I wouldn't think running rich would be an issue. That's probably more about the O2 sensor or CTS.