Fuel pressure ? 02 blazer 4.3, replaced fuel pump ( AC DELCO).. truck does not start just cranks. When key is turned to run position with a pressure gauge hooked to the schrader valve it only goes up to 10 lbs, shut the key off and then back on it goes up to 20lbs, turn the key off and back on it goes to 30 lbs,, WTH could be the problem? "Spider injectors"- "Fuel pressure Regulator" I`m at a loss. I tried the search function here and not finding what i`m looking for unless i`m not putting the correct search info in. Anyone have any ideas? Thanks in advance guys.

 

I'm a dumb@55, so maybe I shouldn't give advice, but I just had the opposite problem of too high pressure, working on the same engine. In the end it was a kinked line, but in the process I replaced fuel pressure regulator, (twice) and rebuilt the injection spider.

Rebuilding the spider wasn't that hard, took about 10 minutes. You just need the $12.99 kit from autozone, unscrew the plate off the bottom, pull the injectors out, replace the orings and pop them back in (with a little lube or they don't go in at all). I would totally suggest doing this as a while you are in there type thing to take care of your Fuel Pressure Regulator, which is probably your problem. It might be either, but you don't want to do this job over and over again like I just did. It's pretty straight forward to remove the plenum cover, just a lot of time consuming work, and you will also need the upper gasket set for that, which is about another $20. They have a bigger one that replaces the lower gaskets also but I doubt you want to go that far. Good luck dude

 

how high was the pressure yours was having?

 

First, change your fuel filter. Did you look inside your tank while it was open?

While you have those lines apart might as well rig fittings to test the pump absolute pressure
Go here, scroll down

https://blazerforum.com/forum/tech-a...agnosis-23038/

DW: Well, now ya know. Actually it's part my fault.. I should have suggested the return line first thing.

 

Listen to this guy, he's smart. I think someone mentioned fpr or kink and I just missed it. Well I got a full tune up on the thing. A full full tune up!

 

If pressure rises with each key cycle, as pettyfog mentioned, first check the fuel filter for restriction, then check maximum fuel pump output pressure and leakdown. Must be 73psi to 108psi with the pump running and remain above 55psi for at least 10 minutes after the pump shuts off. Also check voltage and ground at the pump module connector.

 

Fuel filter was replaced when pump was done.

 

Next step is check maximum output pressure at the fuel filter, it will require a shut off valve tool. I made this one from parts readily available at an auto parts store and a good hardware store. Cost was about $40.

 

UPDATE: I replaced the spider assembly with the new design "apparently" "Ac Delco" got the truck running finally,,, I had it running for roughly 30 minutes with no problems... I shut it off to eat dinner went back out to do a test drive with it and wala, NO START again just cranking... The NEW fuel pump is`nt coming on again!!!!!!! I`ve just about had it with this thing now..

 

Key ON, engine OFF, fuel pressure must be 60psi to 66psi and must remain above 55psi for 10 minutes after the pump shuts off. At the fuel pump module connector, the grey wire must show battery voltage for ~2 seconds when you turn the key to the RUN position, then drop to zero volts. Both black wires must show less than 5 ohms resistance to ground. The old style module connector:


has a tendency to burn and melt causing a poor connection to the pump. The new style should be soldered on with rosin core solder, don't use the crimp connectors that come with the new pump. Post your results.