I cannot find the actual thread, but I see a lot of posts talking about the common fuel injection problems and how upgrading to the new style caused an increase in fuel efficiency.

Can anyone link me to the thread that talks about this in detail, or provide some basic information?

 

There's really not much to the swap. Buy the new injectors and the bracket that goes with it. It fits in place of the original stock injectors and it's a very easy swap. I've done it on two vehicles. It's worth it.

 

Am trying to figure what this thread is about. Which new injectors? Can you be more specific?

 

1996 and newer 4.3L engines, (8th character of the VIN must be "W") use 6 injectors centrally located in the plenum. There is a nylon fuel line connected to each injector for each cylinder. At the end of each line there is a poppet valve with a nozzle that attaches to each intake port. Over time, the poppet nozzels get restricted or leak fuel, or both. The assembly looks like this:


The new design eliminates the poppet valves and relocates the injectors to the intake ports. Fuel mileage and performance are both improved slightly with the upgrade. If the 8th character of the VIN is "X", the engine already has the upgraded injector assembly. The new design looks like this:


The assembly is available at most auto parts stores, as well as Amazon, Ebay and other online sources, usually for under $200. The Delphi part # is FJ10565 and comes with the necessary bracket. An upper intake gasket set is also necessary to complete the job. With a little practice, the job can be done in under 2 hours using common hand tools. No reprogramming of the PCM is necessary, plug & play.

 

The 8th digit on my VIN is a W so it looks like I have the old setup. Thanks for the info, I found the part on Amazon for about $175. How much of an increase in MPG are we talking? Will I notice any performance increases as well?

Would you recommended someone who is inexperienced try to do it? If there was a guide or manual somewhere I could probably figure it out.

 

Performance and mileage increases depend on the condition of your existing injectors, poppet valves and fuel pressure regulator. Typical mileage improvement is around 5 to 10%. There are several threads in the How-to section of the forum. It's not difficult, but there are some specific instructions that must be followed, and they come with the new injector assembly.

 

Ive done the swap on both my trucks now and would recommend it... my 97 had a leaking pressure regulator causing it to run / start like crap. My 01 was fine but i swapped it as preventative maintenance when doing the LIM gaskets. As said already, when compared to a failing injector you'll notice a big difference in performance and fuel economy... if your spider is fine you probably wont noticed a thing.

 

When I got my '98 Jimmy last summer it had the old injectors. The best mileage I ever got was 18.2mpg. With the new injectors I've gotten as high as 19.8mpg on one occasion and just a tad over 19mpg on others.

If your truck is running fine I would keep the current injectors. If you have any reason to repair the current fuel system I'd do the upgrade.

 

i just installed the same ones from amazon for 175 with bracket. i saw no change in mpg im still getting around 14-15 city and maybe 18-20 highway and iv gone through everything cap rotor wires plugs all ac-delco so i figured the old poppet style injectors where leaking but when i pulled them there where clean and no gas in the plenum. i put my truck on a friends snap on obd2 reader and everything is fine he said fuel trims are good he said the o2 after the cat was bouncing around but that's from the stuff inside the cat falling out. the only thing iv noticed from the upgrade is maybe a little better throttle response but that's about it.

 

So it sounds like I should wait until I am having any problems with my current injection system before making the upgrade?

I am getting about 15mpg, but I do 100% city driving currently.