vjjack04

During two tuning sessions, my tuner has been unable to tune my car as it won't consistantly turn past 4300 - 4600 rpm. The motor is a L92 stroker with L76 intake; I have 38 lb injectors, 90mm throttle body, 2002 Z06 MAF, long tube headers. The motor is in a 97 C5 using the stock ECM. Tuner is using HP Tuner s/w - at the end of the last tuning attempt he found a error code on the MAF and told me that the MAF could very well be the problem. Just want to confirm if we are on the right track. I bought the MAF new specifically for this application. Any thoughts? By the way in normal driving the car does ok if I drive it easy and don't shift past 3500-4300+.

sreve

iTrader: (3)

what did you do with the cam timing? is the VVT full advanced?
unplugging the maf with high oct. spark tables copied to the low
ones will take the the maf out of the equation

Eurospec2

iTrader: (2)

Its not the maf..

Doc

iTrader: (9)

The likeliehood of the brand new maf being bad is pretty slim to none. If this is a brand new setup I would put the car in OLSD {No MAF, No O2's} and calibrate the VE table first. This is not going to be fun with the 97 pcm but it can be done if you are very patient.

Now if it was me, I would yank that 97 pcm and commence with the brain transplant and tune it with my RR. Results are fast and precise.

https://ls1tech.com/forums/corvette-performance/744223-how-99-02-pcm-into-97-97-vette-pics.html

bandit1

iTrader: (12)

Strange thing that you say this as i am having the same problem seems like my 427 with L92 heads and L76 intake dont want to rev up. almost ike it falls flat on its face after 3500 rpms. But I think I have a bad O2 so got to change that and see what happens. I dont have a MAF on mine I am in 1 bar speed density mode. If anyone knows what can cause this let me know.

edcmat-l1

iTrader: (10)

For both you guys, are the tuners logging during the runs/pulls? Are ya'lls motors building vacuum? Or are the 02s crashing, indicating an extreme lean condition? Have your tuners tried a exhaust backpressure gauge? There are definte was of determining whats causing this. Its gotta be runnin out of somethin.

JoeyGC5

iTrader: (24)

I'm with Ed. Also are the tuners trying Open loop mode and speed density to see if the inlet or some external source is hindering the motor?

bandit1

iTrader: (12)

Well I do have a few ideas first off I think I may be having a stall issue as I just installed a 2800 stall and it was made by a guy locally and that was the only other thing I changed. So I may take it out and put the stock one back in and see what happens. I know I am not running out of injector but I am seeing my narrowbands hit some darn low numbers but dont see how on earth its hitting them. I am commanding some good amount of fuel from it in the VE table. But I will put it in open loop and see what happens. Dont think its the exhaust its 1 7/8s kooks with matching Y-pipe no cats and out through a corsa exhaust. Intake has no MAf in it 4 in connecting tube straight to the 90mm TB using an MTI clear lid. Like I said it honestly feels like the trans or stall and since the trans was running great before I changed motors, and all i changed was the stall I am suspecting the stall cause in park if I hit the gas the thing roars hard and fast only when I drive it and go over 3000-3500 does it feel flat but too that point feels really good. Things that make you go hum I can send my tune to anyone that has HP tuners and they can take a look at my tune and logs and let me know what I may be missing