Keith_Shapiro

iTrader: (1)

long story short: I have a 98 Z28 with: 6.0 block, stock crank, JE forged pistons, Eagle H-beams, ARP bolts, 823 heads with .660 springs titanium retainers,231/236 cam 617/609 lift, LS3 intake and injectors, a godspeed (I know, cheap ebay junk but I cant justify double the price for a name on a budget build) 102mm throttle body, 3600 stall. quick overview of the build. I had a base tune done on the car so I could drive it around for a while and make sure I don't have any issues i.e tranny leaks, rear end issues, etc. as soon as I start the car the rpms jump to 2200-2400 rpms, if I touch the throttle at all it jumps to about 4k and wont drop. so I taped off the IAC hole in TB to see if maybe this was my issue, it dropped rpms down to 1200-1400, still not where it should be. I then ordered another throttle body from godspeed. put it on, same issue.

If I take the lid off and cover the maf it chokes way down. I have checked fuel trims and they are 0. I have smoked the intake and no leaks. WTH is wrong with this thing? any help is appreciated thanks guys!

redtan

iTrader: (5)

Sounds like a shitty or incomplete tune.

Why are the fuel trims 0? Is this an open loop tune on purpose?

moeZ28

iTrader: (7)

I have an ebay 92mm tb on my car...usually the iac hole isnt quite perfect and the tps could be slightly turned. These are common issues with these throttle bodies. About 45 minutes of work and they are fine. Just have a tuner check your tps voltage and see if it needs clocked any to idle right. My tuner cut the bolt hols open and added a washer and clocked the tps till the voltage was right and all was fine. The blade on my shaft for the tps sensor was also too small allowing it to turn and not turn the tps. This was easy to fix with a small spring. Just check all that stuff out. Im still happy with mine, it was well worth the $135 I gave for it.

Keith_Shapiro

iTrader: (1)

swapped to a NW 92mm and fixed it. thanks guys

redtan

iTrader: (5)

I really really really doubt that the tune is so perfect that his trims are exactly 0% ALL THE TIME. Even the best tuned cars in the world will have trims jump up to say -2 or +2, but never stay at 0 for an extended period of time.

If I see trims at 0 for an extended period of time tells me the tune is commanding open loop or is in DFCO, not that the tune is dead perfect.