CHevy 4.3L V6 fuel injector spider

[gm280]

I presently have my 98 Blazer with the 4.3L V6 engine's intake removed. It was leaking water and I bought the new FelPro gasket set to replace the older ones to stop the leaks. And as usual, when I do things like this, I completely remove and clean everything to like new again. And that also means I am presently cleaning the spider injectors tubes as well. Not an easy thing to do but I take it slowly and clean everything. However, I see that there are aftermarket and even GM built MFI replacement for the CSPI spider on the market.

My question is, has anybody made the swap and if so does the engine run better and increased gas mileage? I read folks changing to the MFI spider and gaining better fuel economy on top of the better performing engine. So anybody want to chime in whether this is a plus or not. It is basically a $250 swap. What would you do? :noidea:

 

[Volphin]

There are basically two systems on the market. The one you have and the MPI version. The MPI version (which includes an integrated fuel pressure regulator) is best obtained from the dealer. It provides more precise metering of fuel, and as you know, an injector individual to each cylinder. I really doubt that you will see and HP or MPG increase from the swap, it is more to address reliability issues that have plagued this system from day 1. The original spider injector system has be revised by GM twice, with mixed results. So it really comes down to how much you want to put in the truck and how long you intend on keeping it.

 

[gm280]

Okay, I just decided to stop screwing around with the old spider SCPI injector system and bought a new MPI AC Delco spider replacement. With 170,000 miles on it, I just decided to install a newer version and save the cleaning up time for other parts instead. The plastic injector holdins were basically brittle and started to crumble as I worked with them and it isn't worth my time or paying for replacement parts for such an old system. Thanks for the response Volphin and I will post an update when it is all running again. The newer system is a lot more precision and simply a direct plug and play setup. YEA!

 

[Scott Danforth]

Find an 02 or 03 in the salvage yard and buy the intake for $50. Then you get the updated spider and injectors. The motor still sucks fuel, and runs with a slight miss at idle. Seriously thinking of a V8 transplant for my 03 Blazer

 

[gm280]

Find an 02 or 03 in the salvage yard and buy the intake for $50. Then you get the updated spider and injectors. The motor still sucks fuel, and runs with a slight miss at idle. Seriously thinking of a V8 transplant for my 03 Blazer

Thanks for the suggestion, but I already bought an AC Delco new MPI system from RockAuto and it is already being delivered as well. So I will finish up the clean up of all the other parts and install all the new parts I already bought and wait from the new spider to arrive. Done deal now.

 

[bruceb58]

GM had a recall on the 4.3L fuel injection from around 96 to 2003 or so. Was yours changed out under that recall? I believe it was the injectors and this item you are calling the spider.

 

[gm280]

GM had a recall on the 4.3L fuel injection from around 96 to 2003 or so. Was yours changed out under that recall? I believe it was the injectors and this item you are calling the spider.

bruce, I don't know if it was in the recall or not. It is a '98 Blazer but I never was informed of any recall. However, I have to say that this engine never ever given me any issues except with this water leak now. So all in all, I can't really complain with changing a few parts now. The new MPI spider injector system cost $240 delivered. Not bad for the age of the vehicle in my opinion. This is what the orginal system looks like. You can see why they call it a spider injector system.



This is the old system in place on the manifold.


This is what the new spider injector system looks like (this one has been installed for a while. Not my system but a google searched picture). If you can see, the new injector system has the injectors right at the ports at the very end of the fuel tubes. The old system used poppet valves with the actual injectors in the body of the system. So the new system meters out the fuel better and more consistently. We'll see. JMHO

 

[Scott Danforth]

that was the theory anyway. the new system with the magneti marelli injectors became standard for the 03 and the early 04's when the 4.3 and blazer went way of the dodo

idle still not what I would call smooth and fuel economy is marginally increased.

 

[bruceb58]

idle still not what I would call smooth and fuel economy is marginally increased.

Yeah...4.3 is a pretty poor fuel economy engine. The 5.3L in my 99 1/2T Silverado gets better mileage than my 2000 Chevy Blazer with the 4.3L did.

 

[gm280]

Ha guys, you're supposed to give me some encouraging words, especially about the fuel economy. Those aren't encouraging words. :facepalm:

If Ford or Chevy will ever come out with a framed SUV that is NOT front wheel drive, I will probably replace this '98 Blazer. But there is nothing in the mid-size range for me to look at with rear wheel drive. :noidea:

 

[bruceb58]

if I wanted a small SUV that can tow something on a framed vehicle, that would be an easy choice. Toyota 4runner.

 

[Scott Danforth]

Ha guys, you're supposed to give me some encouraging words, especially about the fuel economy. Those aren't encouraging words. :facepalm:

I get about 15mpg on the highway in FL on the crappy pump swill down here, and about 9 in the city. I get 20mpg on the highway as soon as I get north of Georgia, and I get a little better on 2-lane highways (55mph) with the cruise on.

my father's 12 valve Cummins gets 22mpg or better on the highway, and about 17 in the city and weights 2 times as much.

 

[thumpar]

I went from a Safari van with 4.3l to a Yukon with 5.3l. I think the mileage may be better on the 5.3l and it is way more powerful. The 4.3l is a great engine but the new engines are nice.

 

[MTboatguy]

I have not drove a Chev for over 14 years now, my last was a Blazer with the 2.8L I have to say, I am impressed with the 5.3L in this truck I inherited from my Father, lots of power, and still quite good on gas, seems to be a nice engine.

 

[bruceb58]

I have not drove a Chev for over 14 years now, my last was a Blazer with the 2.8L I have to say, I am impressed with the 5.3L in this truck I inherited from my Father, lots of power, and still quite good on gas, seems to be a nice engine.

In my 99 I can get 19 MPG on the highway.

 

[gm280]

Well I did get a huge amount done yesterday on the Blazer project. With my younger son's help, we got everything installed back on the engine with the exception of the new spider, which hasn't arrived yet, and the distributor and associated wires and hoses. We did change the spark plugs and the new AC Delco wires (hugely expensive) and "O" rings and gaskets and everything but the top manifold assembly. So it is really close to running again now. And since I cleaned everything back to new, it even looks amazing under the hood too. :thumb:

 

[gm280]

I also have to say that the old spark plugs we removed, and that was a huge effort by the steering wheel shaft too, they looked to be running very well. And I honestly think they were only changed once before in 170K miles. Obviously they needed to be changed. And the wires as well. They were original, even though the wires didn't look all that bad. So even though the engine had no running or starting issues, all the new parts will only add to the drivability...I hope!

 

[Scott Danforth]

I found it almost easier to remove the bolts in the rag joint to get the steering shaft out of the way definitely easier to get to the plugs with the front wheels off.

 

[gm280]

I found it almost easier to remove the bolts in the rag joint to get the steering shaft out of the way definitely easier to get to the plugs with the front wheels off.

Scott, believe me we did think about that a few times. Seeing the plug and getting to it are two entirely different things. But persistence finally won out. We used a deep well standard socket with a wobble short extension and finally we got everything set up right to remove it. Then another long effort to replace the new one as well. And yes we did turn the wheels/tires a few times to get to it via the wheel well and remove and replace that one plug. All the rest were pretty easy in comparison.

 

[Harritwo]

I have a 93 S-10 with the 2.8L, a 95 Tahoe with the 5.7L and an 04 F150 with the 5.4L. The Ford gets the best mileage, more power, and more comfortable for me than anything else. My 4th vehicle is an 12 GMC Acadia which gets better mileage than anything but has also been in the shop more than anything i have ever owned. Currently has a recall out with no fix available, so i prefer the Ford.