Bombguy99z28

Ok, I had my car pretty much on the dot VE and part throttle wise, I nailed down the VE table very well, then plugged the MAF back in and dialed everything in. This was about 10 months ago when I installed my cam. I broke some things doing heads a few months ago, finally got the car running last week, changes since I tuned it last were heads (5.3l 11.8:1) and ported throttle body. I reverified my VE table, tweaked it where it needed it (LTFTs looked good), and plugged the MAF back in. Now my LTFTs are 25 across almost all the cells down low and around 15 at higher rpms.

Can cylinder heads and a ported throttle body cause that much distortion in MAF readings or do you think my MAF sensor might have gone bad sitting around my garage for 4 months?

ninobrn99

iTrader: (8)

have you cleaned it yet? did you unplug it and double checked to make sure it is indeed the maf??

Bombguy99z28

I did several hours of VE logging and tuning today to nail down my VE table. This was with the MAF unlpugged. I checked it and blew compressed air across it when I was putting the car back together, it didn't seem dirty. Yeah, I double checked afterwards by unplugging it again, its the MAF.

I can scale my MAF table 25% or more higher to try and compensate or I can swap MAFs and see what happens, both of which I'll try tomorrow.

I have other problems too, I'm running 83% duty cycle on my injectors at 4300rpms (the highest I've had the car WOT yet)... lol

I'm going to swap MAFs tomorrow and see what happens.

ninobrn99

iTrader: (8)

i was gonna suggest swapping the maf to see if thats the problem. what injectors are you running? stock? 26.6# right?

Bombguy99z28

yeah, stocks... I didn't think I'd run out of injector till over 425rwhp, but who knows. I'm trying to track down some 28s that someone upgraded from just so I can get the car to the track

ninobrn99

iTrader: (8)

are u messing with the ifrs at all?? they should be stock...which im sure you know

Bombguy99z28

nope, I don't touch em... I pretty much follow the HPTuners guidelines for everything I do to the car

SmokingWS6

iTrader: (1)

Its fairly rare but maf's do fail. Mine failed last month. It froze up around 2200hz car on or off. I swapped maf's and problem fixed.

RedHardSupra

iTrader: (1)

if your VE changed, so will the MAF calibration.
http://allmod.net/hpt to the rescue, enjoy

ninobrn99

iTrader: (8)

https://ls1tech.com/forums/lsx-parts-sale/389749-ls1-injectors-rk-sport-spoiler-camaro-headlights.html
get them before i do..

RedHardSupra

iTrader: (1)

don't get 28s, they're worthless for any sort of usual LS1 power. for up to 400rwhp get svo 30s (36.5#), for up to 500rwhp get svo 42s (48.5#)

foff667

iTrader: (2)

SmokingWS6

iTrader: (1)

I prefer injectors that have the same spray pattern as stock injectors(cone), most svo's have a flat pattern.

Bombguy99z28

Well, I'm broke right now, and I found someone local who is gonna give me his stock 98 injectors for the best price.

Thanks for the help everyone.

Bombguy99z28

It was the MAF. Swapped it out, got what I expected +2 to +6 ltfts... much more reasonable than 25 across the board.

SmokingWS6

iTrader: (1)

Glad you got the maf bug fixed. I think i'll take mine apart to find ouct what failed.

Dont forget to replace your IFR table with a stock unedited 98 table.
If you need one I can pm/email you mine.

ninobrn99

iTrader: (8)

Josh, what other injectors have the same pattern?

SmokingWS6

iTrader: (1)

I dont have them off the top of my head but most Delphi's and Racetronix injectors spray in a cone pattern.