I was wondering for those that have done the 3.4 swap which fuel injectors did you use? My question is I used the 19lb injectors that came with the 3.4 but I was thinking should I have put the 17lb back in. Reason being if the computer is tuned for the 17s then that may be the reason the the excessive fuel burning. Now did any of you tune the computer to work with the 19s or what did you do? Its not that I'm burning alot of fuel but its not as good as it use to be with the 2.8.

Now I was burining alot of fuel b/c I was idling way high around 2.5krpms but after cleaning up the tb and changing out the tps sensor it down to 2krpms when first starting up then when warm drops to just below 1.3krpms.

Thanks in advanced for the feedback!

 

I would put the 3.4 injectors in. They are the right size for the motor.

 

If you haven't done any tuning you must use the stock injectors otherwise the tune will be off everywhere, and that's why you're running rich. It thinks it has smaller injectors than it does and runs a longer pw than it should. So you know, the stock injectors are safe up to ~150 hp.

 

Thats what I was thinking and thats why I kept all the stock injectors. Now once I put those back in, there shouldn't be any effect in the power should there? I mean its running pretty good right now just burning a lil more than normal.

 

Youd be better off rich than lean, you dont wanna blow it up or cause any other damage. it is a larger displacement engine and you dont wanna run lean. i have the 3.4 injectors in mine, and lots of other mods too. yes i run rich, but still get 25 mpg. and just FYI, the 3.4 has 17 lb injectors, the 2.8 has 15 lb.

 

Thanks for that reply dave. I talked to my dad and he said the exact same thing you just did. I haven't done anything to the engine so it would be a little rich. He also stated if I do decide to go with a bigger cam I would be better off with the 17s.

 

Why avoid tuning it? Put in the #17's and tune it up. Here's a link you should check out.
https://www.thirdgen.org/forums/diy-...take-look.html