So I have a 94 Chevy Blazer S10 4.6 TBI, car died while accelerating and later found out that the fuel pump was not turning on. Replaced fuel pump and fuel filter today and still will not start. I can hear the pump running when key is on position so i know it should be fine.Going to check the fuel pressure in the morning. any other ideas or steps after that would be very much appreciated. pls pls pls help!!!

 

Should change the relay as well with the pump, a good parts guy would have sold it to you as well. its under the hood on the firewall drivers side. its a little square box and they are cheap, like 10 bucks. Also, did you change that little sock on the pump too? How much gas was in the tank when you pulled the pump out? Do you have spark too? Whats the condition of the distrubtor cap?

 

already checked the relay by applying 12 volts and it does work. there is spark at all 6 wires not sure if enough. the sock on the pump was changed i noticed it was torn and maybe why original pump went bad. only have 12 psi fuel pressure with the key on even though the book says 54-62. i was told car has to be running for that much psi but it wont run. had at least 6 gallons of gas still cannot find problem. fuel pump runs now only have 12 psi and will not even attempt to start its just the starter cranking over not a sign of any fuel igniting. was thinking pressure regulator or a gas coved rag in the filler tube and a lighter lol. I am tired of throwing money at a vehicle i have heard has bad fuel delivery problems. it seems like multiple parts went bad with the pump.

 

Check the fuel lines.... U should get 55 to 60 psi when key on engine off. Maybe u have a leak somewhere, when u turn key on and then off does the psi drop right away?

 

You really ought to have a peek inside the plenum for a leak. fuel will not even come out the injector nozzles without the high pressure. They need the pressure to open up.

Take off your VORTEC cover and that black hockey puck and look inside there for your leak. It should be black everywhere, if you have any gold spots in there, or puddles in the low spots you have a leak. Your FPR is located inside of this area too. A dead giveaway for a leak that bad - smell your oil dipstick, if you smell gas, its got a major leak inside the plenum.

With your key turned on you should hold around 60psi, then when you turn off the key it should still hold that pressure. Any dropping off is a leak somewhere. Take off those 2 parts and turn your key on, if its dropping to 12psi of the get go, you should have no problem spotting the spray inside the intake through that hole. The "nut kit" is the 2 lines that go from the back of the intake to the spider unit, the "spider unit" is those 6 black legs that attach to the square in the center, and the "FPR" is the gold round thing on the passenger side of the spider unit.

You can do a forum search for "spider injector" and find a ton of information that will help you change this part out should you find the gold washing inside the plenum or puddles of raw gas. It is not a hard change, and there is a link in these forums for a cheap injection unit. If your FPR is the culprit, you can buy a replacement HELP! brand one for about 80 bucks. Or online you can order the whole spider unit with nut kit and FPR for around 300 bucks. Dont even bother going to the dealer for a replacement part, they are going to want at least 800 bucks for it.

Dont give up on your truck, and proper diagnosis of problems will help you save money instead of throwing a pump at a truck that may not have needed it.

 

only 12 psi with key on and doesnt change when key off. it said in the book to squeeze the return line and watch pressure to test for leak at FPR but there was no change but im sure there are other leaks somewhere. the fuel pump went bad and wasnt working at all before i replaced it. of course the filter comes with it and new sock was all needed. going to be entering the plenum area this weekend i need the truck by monday. im hoping that the FPR is the culprit because i may not have the tools to overhaul the whole spider injection system. i took out the spark plugs the other day to see if flooding was happening and there wasnt a drop of gas on any of them so im going in the plenum but i will keep all suggestions in mind. also there are no clogs or leaks up to the plenum i disconnected every fitting to make sure it was clean fuel and the 12 psi i do get out of it. how difficult to change FPR and injector.

 

You dont need any special tools to do the job. A 10MM deep socket to get the upper plenum off. And a Torx T15 or T20 screwdriver to get the screws that hold the FPR on. If you have to take the nut kit off you can do it with regular 9/16 wrench Make sure you use a magnetic screwdriver (or stick a fridge magnet onto a regular screwdriver to charge it) so you dont drop those tiny screws into the intake. Good luck and come back here if you need a hand.

 

Are you sure you got the right pump? That's enough pressure for a TBI motor, but not (obviously) for a CPI.

You have a 4.3 CPI, yes? Or is it TBI? I didn't think there were any TBIs in '94....

 

found the problem thanks to leeann... another case of wrong part number going to go yell at the guy at autozone... thanks again for all the help

 

Sorry you've got to drop the tank again...