Hi everyone im new to this so please help me out if possible
I have a 02 blazer with the 4.3 vortec with 139000 it all started with a small drip in the fuel return line so fixed that and put a new fuel filter on then it didnt want to idle and it had a very strong odor of gas so i took it to my uncle thats a mechanic he put his fuel pressure gauge on it and it was pumpin 83lbs of pressure on idle so i drove it a couple days hoping to clear up but never did now it wont idle and if you give it more than 1/4 throttle it starts spitten sputtering and backfireing. Has anybody ever had this problem or have any suggestions on what i should do next idk if its a bad fuel pump now or could it be a injector cause now on the fuel pressure test its bounceing all around from 42-80 Thats after putting on the new fuel pressure regulator.

 

fuel pressure test, engine off key on. should be 58-65 lbs. turn key off and it shouldnt drop below 55 for 10 minutes. post results

 

It bounces from 40-50.but dont drop wuth key off

 

40-50 no good, takes 50 lbs to open poppets on injectors.

 

So what are u thinking bad fuel pump?

 

possible

 

That you mention a 'very strong odor of gas' indicates that you might well have a leak at the fuel filter and/or the return line. Even the slightest leak at the fuel filter fittings will, understandably, result in a drop in the fuel pressure. Any and all fuel system leaks should, of course, be your first and foremost concern at this point.

Beyond that, a bad new fuel pressure regulator and/or regulator 0-rings could also be the cause of the low fuel pressure. Aftermarket (non AC Delco or Delphi) regulators are known for being no good right out of the box. A direct fuel pump out-put pressure test and flow test should determine if it's either the fuel pump or regulator. Other causes could be: an improper (new) fuel pressure regulator setting/adjustment, leaky injectors, and/or fuel line system hoses or line O-ring/fitting leaks (from the tank to the regulator).

But I would again say that you need to first triple check the return line and fuel filter for leaks due to you mentioning a strong odor of gas after working on said components.

 

No leaks anywhere on the fuel lines gonna try a 200 dollar fuel pump hopin that fixes the prob doijg it thursday cause got church tonite.

 

I very much recommend that you go with an AC Delco or Delphi brand pump/sending unit. But then again, either brand goes for around 200 bucks with the fuel level sending unit so, it sounds like you might be on the right track...

Note: be sure that you disconnect the tank vent valve lines (from the metal lines attached to the frame rail) before you lower the tank even a little bit (these vent valves are located on the rear and front top of the tank with the front unit being easy to miss). These vent lines connect to very easy to break plastic vent valves that are permanently attached to the tank (break one, and you're looking a buying a new tank assembly).

Also consider soaking both tank strap nuts and threaded rod sections with a good penetrating oil at least a day before you start. You probably already know about the above issues, but I thought I'd mention them anyway.

 

Thanks for the help ill have to mention that to my uncle who is doing it for me today hes a certified mechanic so he might know but going to say something anyway just praying this will fix it