My mechanic was telling me about this 'upgrade' GM has for our 4.3trucks that is some kinda fuel injector harness upgrade, or something like that, and it can improve gas mileage and prevent injectors from overspraying.

What is this thing called?

 

when u find out let me know

 

MFI injection spider. Run a search on it and you should find plenty of posts that I made on this.

When I replace my intake manifold gaskets, I will be installing the updated MFI spider (I'll do a write-up).

I do not think there will be much if any performance increase if your original SCFI spider was working properly, however, by getting rid of the problematic poppet nozzles, it is a very good plus, especially seeing as I plan on keeping this truck for a long time to come.

 

Kyle,

I have installed the updated MPFI injector unit and I got to say that there really is not much to it. All you got to do is remove the upper manifold plenum with all the required gas lines etc and once that is off it is a simple pull and push after that... pull the old black block out and push the new one in, then put the new injectors in the respective locations on the block replace the upper plenum and gas lines...30-40 min. depending on how much you take off the upper intake. I removed as little as necessary.


And you are correct it does not improve fuel mileage.

 

I have had my SCFI spider out for o-ring replacement, I know what's involved. I'm not worried about it in the least, but I will be updating to the MFI because I know my poppet nozzles aren't spraying correctly. I performed an injector test with my scan tool when I had my plenum off last time and the spray pattern was all over the place from nozzle to nozzle. The smoothness and all always gets better after I run some injector cleaner through the tank, but will degrade after awhile. I just don't want to have to deal with it.

 

Thanks! Much appreciated!

 

I think it'll only improve gas mileage on a higher miled engine, as the poppets might be leaking quite a bit and whatnot...

Otherwise, if they're still in good shape, you won't notice any change...