Fueling & Injection - Do I need a tune if i change injectors?

Do I need a tune if a changed injectors from a 2000 TA which i think are 26lbs to injectors from a 2002 ls1 that are 28lbs?

Yes you do.

What will be the side effects if don't tune the car?

depending on how big of a jump the maf/o2's wont be able to compensate enough meaning your a/f can drop well below stoich destroying your cats & possibly washing the cyl walls creating all sort of havoc

Yes, you need a tune or you will be running way rich.

Why switch from 26 to 28? if you're gonna spend the money at least go with 36ers.

Well, I think they are causing my car to turn off at 5K rpms and I want to leave stock for now...

you think your stock injectors ar causing your car to turn off?

As i understand you just change the duty cycle in the tune.

As i understand you just change the duty cycle in the tune.

could you explain?

they shouldnt make your car turn off. I used a set of 28# injectors on my 2000 (came with 26#), and its been up past 5k a couple times. I just used these so i could have a little more flow, and they came with my LS6 intake, so i figured why not. But it definetly smells like its running a little rich.

i used 28's in my heads/cam car and saw 6800+ many times without cutting off ;)

Well, something is happening to my car when I reved close 5K. it seems like the fuel is cutoff, but I dont' know. This what happens I take it to 5K andI want to shift and push the gas and nothing it starts sputtering and then sometimes it stays on and sometimes it completely turns off. It also happens if i reved up in neutral its a manual transmission. Someone in this forum said it could be the crankshaft position sensor. What do you guys think?

My RPM gauge stops working also, could that be related? There are times when the car turns off and I turn it back on and the gauge doesnt move but the car is idling right.

It has been doing this ever since i bought the car in 2003 and since i don't race it I haven't noticed it that much

i severely doubt a tune or injectors will fix those issues.

i severely doubt a tune or injectors will fix those issues.

I concur. Something more than the injectors is the cause of that.

any ideas on what it could be?

Are you throwing any codes? It sounds like either Cam Position Sensor or Crank Position Sensor. If it is the Crank PS then after you replace it you will need to perform a relearn. Cam Position sensor you will need to remove the manifold to get at it. You can find all kinds of walk thru's around here.

Well my engine light came on after turning off a couple of times but since it was late I went home and the next day tried to take the car to the auto parts store to find out what the code was but when i turned on the car no code. So I will probably reved it up so it can turn off during day so I can take it and get it check out. I wish I had a scanner.

You should still take it somewhere to be scanned. My predator see's 8 Trouble codes that are not specific even though my SES light is not on.

there is still a history code in the pcm that can be scanned. It may also be called a pending code, but either way most scanners can read those and you will find out what was going wrong.

Well, something is happening to my car when I reved close 5K. it seems like the fuel is cutoff, but I dont' know. This what happens I take it to 5K andI want to shift and push the gas and nothing it starts sputtering and then sometimes it stays on and sometimes it completely turns off. It also happens if i reved up in neutral its a manual transmission. Someone in this forum said it could be the crankshaft position sensor. What do you guys think?

Has the car been tuned before? Your rev limiter wasn't changed on accident was it?

As far as I know the car has not been tuned but its possible since i bought it used with 43K miles, so thats a possibility. I was wondering just today if the PCM could store codes that could be retrieved later, thanks for answering that question for me. Hey do you know what parts make the rev limiter work, is their a sensor or something like that in the engine?