I replaced the fuel pump (186,000 miles) not because it stopped working, but because the fuel gauge didn't work. Problem solved.
Fuel filter replacement at the same time.

My BIGGER problem was hard starting and really TERRIBLE gas mileage. (220 miles to the tank).
The crappy CFPI spider assembly was old and tired and the fuel pressure regulator was leaking into the intake. THAT WAS THE PROBLEM.
I purchased a new Delphi unit and started the disassembly taking NUMEROUS pictures as I disassembled the intake, so I didn't mess it up too badly putting it back together.
The teardown took approx 75 minutes (one of the spider legs removal prongs broke so I spent 15-20 minutes with 2 tiny screwdrivers tinkering until it finally popped (BIG SMILE OF RELIEF). After that, it was fairly simple other than the bending/manipulating of the spider legs into the orifices. Did a decent clean up of the surface area, then installed gaskets and put it back together in about another hour ( I worked slowly). Once it was put back together completely, I said a quick prayer and started the engine. It ran terribly and I started fearing that I installed one or two of the injectors wrong.
Then to make my struggles even worse, the check engine light came on.
AAARRGGGG.
I didn't give up. It DID start. I let it idle for about a minute or so, then took it for a ride. RPM at idle was 1400. I stopped at a light about a mile away and just sat for a moment. Suddenly, the idle came down to about 600. The car started riding normally, in fact, it ran better than I remember it riding,but the check engine light was on so I drove it home.
I removed the negative battery cable for 5 minutes, then started it back up. Check Engine light remained on. I turn it off and removed the POSITIVE battery cable for 5 minutes.....BINGO.
Starts perfectly, No check engine light, and it runs flawlessly. Started it again today and drove it with no issues. Had better acceleration. I'm waiting to see if I get better gas mileage, but the MPFI spider is DEFINITELY the answer, and the installation is not too terrible!!
If anyone has questions or need some pix, let me know.
I know most on here already know how to do this, but I just want to help if anyone needs it.

 

What's the MPG now?

 

I just did it.

 

I just did the exact same thing to my 02. Runs really good now, new pump old one failed, new filter just in case and new MPI unit FTW.

 

I feel for ya when things start going wrong and you have to just keep moving forward. I end up stopping at the point something goes wrong and have a beer and get my head right then have at it again. So I am glad it is running better. I'm not sure what or where the CFPI spider is? And you had also said about the MPFI spider what & where and how is it different from the CFPI spider? Now did you have any codes that lead you to the CFPI spider problem? Or would a fuel pressure check help point to it? Any photos would be helpful. Sorry for all the questions but I really don't know my way around these 4.3's . I so far have had good luck with my '01 Blazer 197k I have only had things like tune up, alt, fuel pump, hub bearings and rebuild front end. So I am trying to get up to speed so when things do go bad I'll have an idea of where to start. Mind you I'm good with a wrench and problem solving just don't know the in's and out of this Blazer.

 

Yeah...i'm only getting about 220 miles to a tank....that normal for these 4.3's? New to the forum and Blazer family...


Can somebody explain the Spider thing to me?


sorry bout the threadjack....

 

That's NOT a threadjack. You need help and I just did it.
what questions do you have??

 

I'll be back to answer these questions when I get to work....Driving now

 

I'm sorry to bother you over questions to where I can get the main ones answered per Google, the search engine on the Blazer forum wasn't any help or I couldn't find what info I wanted..

So after reading this it adds a new set of questions.
GM VORTEC CSFI to MPFI CONVERSION

But before I do I need to let this first all sink in alittle. For me it is like trying to pour a 12 oz beer into a shot glass. It just won't all fit at one time. So one shot glass at a time.

 

Thanx!


Just got an '02 LT 4dr 4x4 with 113k miles. Guy I bought it from said it would only start in 2nd. Replaced the shift solenoids and that fixed it right up. But getting a P0449 and P0410 code...


So what exactly is this "Spider" thing? Could that have something to do with my gas mileage? Planning to do change out sparkplugs and figured might as well change out wires too.