BOTTLE ROCKET

iTrader: (4)

Well; Had the car (H/C 99 vette) pretty much tuned, but was at 97% with my 28lb injectors. I purchased some rebuilt 42lb, scaled them in and now the car absolutly WILL NOT RUN. It starts up, sputters and dies. If I manage to get some rpm, it won't hold it (dies)
I have lightened up my MAF table to subtact some fuel, and then tried lowering at least the idle area of the VE table (which was perfect!) with no luck
Any sugestions on where to start?
Thinking of putting my 28lb injectors back in, downloading old tune and seeing if it is an injector issue, but don't know what that will tell me. I'm confident the injectors are good
Note. took my flow at 58lbs and put it in 0 slot, added the difference from the old 0-80 (2.79) and added that to the 42 and entered into 80 slot. Interpolate between corners.

BOTTLE ROCKET

iTrader: (4)

Well, as an update for anyone else, I found the issue. I had gotten my MAF table WAY off somehow I unplugged the MAF to start my search and it ran perfect, so I started searching for leaks, etc. I looked at my last tunes, and the MAF #s were crazy off compared to them, so I really don't know how they got so far off :shrug: Copied and pasted and it ran great
I do have another question I'd like to throw out there. I now have the MAF #s pretty dead on for part throttle (havn't done WOT) but at low rpms, under load (OD) I have a "miss" or "skip". Looking at the logs, the only thing I see are times when the O2s seem to "doze off" They BOTH will actually quite recording (working?) for as much as 15 frames, or 2-3 seconds. Could I have some O2s dying, or is this common. Hadn't paid the O2s much attention in the past becasue Ive had no issues.
Thanks

crainholio

iTrader: (2)

If you only scaled the Injector Flow Rate table, and didn't do the other tables I posted, you're not done yet.

And if you're trying to tune your new injectors by using the MAF and/or VE tables, you're going about it exactly the wrong way.

BOTTLE ROCKET

iTrader: (4)

So although these are stock 28lb GM injectors that have just been rebuilt to flow more, I have to adjust more than the flow rate table?

crainholio

iTrader: (2)

Talk to the shop that modified them.

BOTTLE ROCKET

iTrader: (4)

I did (a vendor here) and he said install, scale and go.That's why I selected them
1 Becauuse they would flow identical
2 He said they I could install, scale them, and start tuning.

98transbum

Hey how it running? I did the same thing till I put in my new stroker,but my ls1 ran great on my resized 42's.. My tune was great with just an ifr change and a few tweaks. So I don't understand what else to change anyway. Good luck trying to figure out the rest. All the tuners have a lot more knowledge, but this. Works for me.

crainholio

iTrader: (2)

Maybe post your IFR table here for others w/ those injectors to look at.

What math did you use to re-scale the table?

BOTTLE ROCKET

iTrader: (4)

Here's the math

Note. took my flow (42) at 58lbs and put it in 0 slot, added the difference from the old 0-80 (2.79) and added that to the 42 and entered into 80 slot. Interpolate between corners
98 TB;
It runs like a scalded ape. I just installed AFR 205s to go with her custom "mid size" cam, and it hauls BUTT!! (and I'm used to an 700rwhp blown car )
I just have to tweak the MAF to get a consistant 12.8 and it should be in good shape.