This is not a new topic but this is my experience with a common problem.

Symptoms: needed a complete tune up because gas mileage was poor, "stomp on it" response was poor, hadn't done it since buying the vehicle used

Did the tune up: plugs, wires, cap, rotor, fuel filter, oil change, oil filter, air filter, CLEANED MAF SENSOR ( DO IT. IT'S EASY. YOU'LL BE GLAD YOU DID).

Still some hard starting but, otherwise truck ran awesome!!! 3 mpg better btw!

Can't leave it alone... Why the hard starting?

Replaced the IAC valve because on other fuel injected vehicles that was usually the culprit. Result: no better starting AND some new weird surging in idle and after putting it in gear coming out of the garage. (even after taking it on the highway to reset the ECM)

Shortly thereafter the starting gets worse and once or twice the engine bogged down dramatically on freeway when I really needed it to go. (Sorry, Mr. Trucker!)

OK... read all the posts about fuel leaks... sure sounds like my situation... STILL, fuel pump is original and high pressure ones for FI do have to be replaced once in a while...

Fuel pressure test: Ignition on- right up to 60 psi... turn ignition off- drops to 50-52 then within about 1-3 minutes drops slowly down to 40, then over the next 15 seconds drops quickly to 0 psi.

Read the posts again about leaking inside the plenum and ... sure sounds like that could be the problem. OK, check Autozone and they DO sell a complete FI spider with a pressure regulator included ($210.00) but there are a few too many posts where that didn't solve the problem AND EVERY FRICKIN TIME I TOUCH A PLASTIC CLIP ON MY 96, IT FRICKIN BREAKS!!!

I decide to do the fuel pump ($210.00) first because a brand new spider is going to be a major bitch to put in and it's going to be one or the other anyway and fuel pump seems easier and past experience with other vehicles says that may be the problem.

ALSO, CHECK STEP 3 AND 4 OF SWARTIKK's GREAT DIAGNOSIS OF FUEL PRESSURE PROBLEMS... GOOD INITIAL PRESSURE FOLLOWED BY IMMEDIATE LOSS OF PRESSURE IS LIKELY A FUEL PUMP CHECK VALVE (didn't see that till after the job was done, though...D'oh!)

Well, changing the fuel pump on a Blazer turns out to be a BITCH too! But, it's done and these are the pressure gauge readings (never even removed the pressure gauge from first test):

Ignition on- right up to 60-62 psi. Ignition off- within the next 5 minutes gradually goes down to 45 psi, then over the next 20 minutes gradually goes down to about 20 and after 40 min. it is constant at 15 psi.

CONCLUSION: I probably have a small leak somewhere in the spider but the truck is starting quickly EVERY time and freeway performance is a dream. Until performance changes dramatically, I'm not touching that whole plastic mess on top of the engine!

I suggest if you have these troubles, DO THE TEST and start with the basics...

ARE YOU STILL RUNNING THE ORIGINAL FUEL PUMP???

If a brand new spider isn't getting good CONSISTENT pressure, IT MAY BE A WASTE OF MONEY AND TIME TO REPLACE IT.

The fuel pump was a bitch and if you're not sure you can do it SAFELY take it to a garage!!! I know we garage Dads think we can do anything, but BE SURE YOU CAN BE SAFE!!!

That being said, the pump I got at Autozone came with WOEFUL instructions ! You have to replace one of the electrical connectors with a new one and I found out too late that the crimp-on butt connectors they give you need to be put on the correct size wire... start with the fatter wires and if the butt connector doesn't go over the stripped wire, you're using the wrong size. Honestly, I think they should be soldered and heat shrunk but I was too paranoid about blowing myself up to do it that way!

So there you have it! My happy ending but, MAN! FUEL TANKS ARE A BITCH!!!

 

Motorcycle jack FTW!!! Put it under the tank, loosen the straps, take them right off, and lower the tank on the jack. Best to get a low profile one, with the truck on ramps you can pull the tank out with the jack still under it.

But since you're already done, use it for next time... Because we all know there will be a next time! :P

Joys of owning a blazer!

 

midnightmekanik (fun name!),

Yeah, thanks for the heads up on removing the straps and dropping the tank down with a jack... in theory it's easy, that's why I did it instead of cracking open the top of the intake plenum.

Here's the things that made it a bitch:

It's all about the clearance for your hands and the length of hoses and cables.

1) Cant siphon gas out of the tank because filler pipe has a screen so I'm dropping it down with at least three gallons of gas rolling around in it.
2)Loosening the filler pipe clamps and pulling the hoses off was easy... putting them back on was hard because the the edges on the filler pipe are sharp and it was hard to get the hose back over it without cutting the hose on the edge of the pipe or getting one small bit caught and having to back off and start again...all without much clearance for two hands. Total time to get just those two hoses back on : 30 minutes!!!
3)Quick release connectors made of plastic... I got lucky and had the kind that you can undo with your fingers (if you can get to them) but I wouldn't have had the tool if it was the other kind. Plus, they feel really brittle so I was EXTRA careful not to break them. Two you can get to before you drop the tank, one more has to be undone at the fuel pump... again, all plastic... and that hose is barely long enough to reach the pump when the tank is installed much less dropped down enough to get the TWO screwdrivers I had to use to get that "quick release" connector off.
4) Same problem with the electrical connectors... getting them off without breaking them with no hand clearance.
5) Putting the new connector on the new fuel pump was easy enough but butt connectors seem a bad way to go. Sure enough, even though I had checked the tightness of the connections before hooking things up, by the time I was trying to get the filler hoses hooked up, I looked at the top of the tank to see if something was in the way (there was, a fuel pump hose) and what do I see but a bare copper wire shining in my worklight's beam. Moving the tank around had pulled this cable out of the butt connector because there is so little slack in the wiring. I didn't even try to figure out if that would have sparked the first time I turned the ignition... just fixed it .

So, for me, fuel tank was a bitch. Your results may vary.

I highly doubt it, though.

 

Sturj... haha you're copying me, jk. but yeah I did my fuel pump a year ago and it was the biggest bitch in the world haha.