1999 s10 blazer 4.3 vortec
Hello folks, well i use to think i was somewhat of a shadetree mechanic, but doubting that now. this started 3 weeks ago, i poured some Heet into my gas tank at home with a quarter tank of gas, drove 4 miles to the gas station and filled up. wouldnt start upon trying to leave, would run with starting fluid. so i towed it home didnt hear fuel pump, come on so ordered a new one. spent days trying to figure out why no voltage to the new pump, read articles on hear redid battery cables, dissasembled relay box and cleaned. none of that seemed to work until another day of troubleshooting, all of a suddon it cranks. yay until i discover it loses pulse signals i guess and quits after 5 seconds. verified all fuel pressure checks and they are in spec. who has the magic answer, thanks

 

Need a little more info. What year, make and engine do you have? And is it TBI or Vortec?

 

Still not running, has anyone had this problem before?

 

Good lord. LOL Just Google blazer fuel pump and you'll see who has had the problem before. No offense but this problem seems to plague every blazer owner on all the forums. After Googleing you'll find most recommendations lie in checking every inch of the wiring harness for shorts, replacing the fuel pump again, replacing the spider assembly and so on and so forth. I've been fighting an issue for almost a year and still have not seen ONE person report back the solution to their "fuel" issues.
Have you checked the ECM IGN fuse? how about the oil sending unit? If oil sending unit detects low oil, it shuts off power to the pump. Hoes your oil level? the fuel pump relay in the glove box? all of those supply power to the pump. Then there is this special harness that goes right before the fuel pump that sometimes goes bad. Some even recommend cutting hole into floorboard so that you can service the wiring harness rather than pulling that flippin tank out and changing the pump for the third time to the tune of $250.
Sorry to sound so negative but I've been reading "blazer fuel pump" issues for almost a year. with no solving my issue.
How uncanny the issues we have. Mine blows the ECM fuse 10 times ina row, then the next day, no blowing fuses. Until I back it out of the driveway. Then bam. Blown fuse. Blows 3-4, then starts. Solid 60psi fuel pressure while running in driveway. Then put into gear, no blowing fuses. NO codes thrown. I've wiggled every harness, replaced computer, coil, IGN Module, MAF, MAP, relay dist cap rotor, plugs wires. It started blowing fuses in March, Did not blow all summer. Then 3 weeks ago. Bam. Everyone tells me "fuel pump, "fuel pump", I just cant believe that holding a solid 60psi at idle and under power in driveway shows a bad fuel pump. But, sigh, I could be wrong.
I even bought the ODB2 software and hooked it to my computer. No codes except for one time multiple misfire. Well, no sht. When it dies I guess it does misfire. That only happened once.
Man I wish you luck.I feel for yas....

 

The fuel pump wiring harness and connectors are where I would think the problem would be. I'm on my 3rd fuel pump in 3 years and every time I get a new one the install instructions reccommend replacing the connectors. Clean the connectors with electrical parts cleaner and maybe a little wire brush action and see if the pulses continue to show intermittent.

 

Do you have any idea why you are replacing $250 fuel pumps at the rate of one per year? That sounds distressing.

 

Best I can tell is that the fuel pumps are just crap. I replaced the fuel pump ONCE in my 89 K-5. That was 8 or 9 years ago. I have used AC Delco replacements on the 99 and they generally come with a one year warranty. At 14 or 15 months they just take a dive. The good news is that I can change one out in about 2 hours by myself now.

 

argh. I don't want to hear that. Yeah I think I've out one pump in my 79K10.
I bought the GM Blazer pump from the dealer about 3 years ago. Damn... 2 hours huh? Got any tips or short cuts for that? When i did it I think it took me about 2 half days. Never cussed so much.

Any experiance with the CFI to MFI conversion? I'm getting ready to do that first before I pull the tank. I keep getting rough idle with multiple misfire code. I just cant bring myself to believe the fule pump with 60psi is causing that. It leaks down fairly drastically when cut off and the ign on though. I'm figuring I need the conversion anyway. WTH... its less than a months car payment. LOL

 

The first thing I do when I replace the fuel pump is to drop the spare tire. Once the spare is out of the way, you can reach in from the rear of the vehicle and disconnect the electrical connectors and the quick-connects on the fule lines. Spray a little w-d 40 on the filler neck hose and the other little hose and let them soak a little while. Only take the filler hose loose from the tank - no need to remove the whole thing.

I use a floor jack and a 2x6 board about 3ft long to support the tank while I loosen the straps. The less gas in the tank the better - especially when putting the tank back in. Once the tank is out, clean all the dirt and gravel off of the top of the tank so it won't fall in. The only other trick I have discovered is that when you put all the clamps back on your hoses, turn them in a way that you can get to them easily the next time. Good luck.

 

Well i see a few comments here but not pertaining to my problem except the fuel pump harness, well thatwas replacedwith the pump. a few more days of pulling hair, checking connections, pulling on wires, now the problem has moved to roll the dice and the fuel pump comes on sometimes and truck runs for 20 minutes(thats how long before i turned off) or to no power at the pump at all to crank it. So power is coming and going whenever its in the mood but runs now instead of the 5 seconds and then cuts off. Anyway i have ordered a ecm/pcm and am thinking about the regulator just for the hell of it. I had the intake off about 6 months ago for the notorious coolant leak anyway. so that want be a big deal. any other ideas bring it on i see a couple of other people on here with the excact similar problem but nobody ever comes back and says what fixis it......or its not fixed lol thanks