I am getting a retune this fri . Im swapping my 16lb ones for some 24lb ones out of 04 lq9 and was gonna be driving 300 miles or so. Would my truck be ok to drive out there like this. thanx

 

It'll be fine.Just gonna run rich

 

it should be ok, just dont stomp on it until you get it tuned...

 

...I didn't even know that there were 16 lbers

 

no, wrong, very wrong.
when you change the injectors without changing IFR, you will be commanding the same old (higher) injector pulse width than what you should, dumping a lot more fuel than needed. this isn't "just dont stomp on it" case, it will overfuel at ALL TIMES, idle part throttle, wot, whatever else you can conjure up.

if you're going to a tuner, do it on old injectors, go there, install the injectors, get the tune done. if you don't, then the overfueling will potentially kill your spark plugs, your O2's, and will contribute to the earlier demise of cats.

 

yeah 16's to 24's is a very big jump to let the ltrims/strims try and handle...I agree with RHS in that you should AT MINIMUM get your IFR table moved before you install them...this should get you within 5% of where you need to be which is much better then 40%

 

I also installed some longtubes and pulley. It s already throwing codes PO135 and PO155 ( 02 heater falfunction pre-converter sensor) . Man Im worried/ I wanted to make it to the track tomorrow. btw the injectors are not installed yet and its doing this!!

 

just means the front o2's arent heating up quickly enough because of the long tubes.

 

If you have a fuel pressure gauge turn your pressure down as low as it will go and you should be able to make the trip just fine. Then turn it back upto stock for the tune. Look at your fuel pressure regulator and you'll see the adjustment screw right in the center. You'll need a tamper proof torx bit to adjust it. They get a little stuck over time so spray some penetrating lube in and out the day before to loosen it up. Your stock pressure is 62 running with the vacuum line off. The 24lb injectors will flow 16 lbs at 28 PSI but in my experience the factory regulator won't go below 30-31 before the screw spring clears the regulator diaphram. I run my truck on a stock tune with larger marine 8.1 injectors set at 30. It's long term fuel trim average is -12.5% which is well within adaptive limits and doesn't set a code.

Vernon