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bikewhisperer
April 21st, 2007, 10:37 AM
I have just recently picked up V2 and I am in the process of getting aquainted with the software. Looking forward to making the most of my 2004 Tahoe.

But my question is this, a friend of mine owns a 1998 Z71 5.7L. The only engine mods he has done are air intake. A cold air intake, spacer, MAF sensor, and some machined spiral thingy that makes the air all furious. I dunno exactly what all he has done, but it seems that he has forced alot of air into that engine....enough that the amount of fuel appears to be no longer sufficient. He is experiencing some pinging under load, and according to a local shop that he had scan it, the LTFT are at 20%, which he was also told is maximum for that vehicle.

What I want to know is if this problem is something that can be fixed with this software? My inexperienced thoughts are if that maximum LTFT can be raised, perhaps that would help?....

Maybe a simple (stupid) question for many of you veterans, but I appreciate any feedback.

joecar
April 22nd, 2007, 06:08 AM
bikewhisperer,

Welcome to the forum... :cheers:

Some commenets regarding your friend's Z71...
a. technical consensus is that the spacer on the intake may not be worth any increase, but it's debatable.
b. the tornado spiral air thingy is also questionable, and if it has any sheet metal components these may break off and be ingested... at best it restricts airflow.
c. the aftermarket MAF sensor may be the problem... it may be causing the PCM calculations to "under-air" which then "under-fuels", which then causes the O2 sensors to indicate lean, which then causes the PCM to add 20% more fuel to maintain stoichiometric AFR...
or it could be due to failed O2 sensors, or due to an air leak downstream the MAF sensor.

LTFT tending away from zero indicates a problem.

There only stupid questions are the ones that remain un-asked. ;)