Todd157k

iTrader: (5)

ok, here's the long story... 04 Z06, bone stock.. put on a Procharger, on the dyno.. it ran out of injector but ran great. Took it off the dyno, and replaced the injectors with Siemons 60 lb. But now the tuner is at the wall. The MAF is not responding correctly. The car idles/runs great in SD, but you plug on the MAF and it blurburs like it has a cam. Does the same whether its plugged in or unplugged. We also tried a different MAF. No change.
The only thing that was done between the tuning sessions (other than changing the injectors) was that they had to find a headlight issue (they were stuck up, turned out to be a fuse). Other than that, NOTHING was touched.

Any suggestions as to what is up with the MAF? anyone ever have something like this?

Obviously we are going to start looking at all the electrical stuff that was touched during the headlight issue. Maybe the grounds too.

Todd157k

iTrader: (5)

Bueller.....


Bueller.....



Bueller.....?

jimmyblue

iTrader: (11)

Question 1, what do you have for a MAP sensor and OS? A blower
car at WOT, needs a 2-bar setup. If you faked it into line keeping
a 1-bar sensor, there may be a lot of bullshit embedded in the tune
even if the result is right.

The speed density tuning method of messing the VE table around to
get proper AFR out the back, goes and bundles up all errors that
may be present and pushes them onto the airflow side even if some
are not airflow related (like fuel pressure, injector delivery). Just like
the old days when people were trying to fix airflow errors with the
IFR table. If you "fix" fuel errors with the VE table, those fuel errors
are still there and the MAF airflow is not "fixed" at all.

You might start by looking at the Dynamic Airflow and the MAF
airflow values, for how much divergence you see. Plug in the MAF
and raise the cutover boundary to 8000RPM so dynamic airflow
stays active and you can see the SD-computed airflow. If there
is substantial (like maybe more than 5%) disagreement, figure
out what non-airflow errors you dragged into the VE table.

12secSS

iTrader: (30)

The MAF table can only read a max of 47lb/min of airflow, your P1SC (depending on the boost level, I figure it to be 8lbs or so based on you needing 60lb injectors) will easily surpass this. You need to go SD at your power level.

Also, do you have your BOV/BPV routed back in to the system, or is it spent out to atmosphere? You need to cycle it back in after the MAF, if not done so.

Just some thoughts.

Todd157k

iTrader: (5)

Jimmy - Yes, it's still a 1-bar setup. We'll check that out. Being that Charlie is pretty well known as a tuner, (LAPD) I'll see what he's run into along those lines. There is a BAP on there and 4.10 pulley so it should be around 7 lbs of boost. The 38lb injectors that were on there ran great up to 500 hp but were way tapped out at 114% dc.

12secSS - Yes, I have a BOV. it is spent out through a filter. I haven't seen that type of setup, but will definitely look into it. Would maxing out the MAF tables even show up at idle? It doesn't idle for crap w/ the MAF.. unless zerod out.

moehorsepower

iTrader: (3)

For your setup, stock maf and 1 bar is fine, did the tuner change the frequency of the maf? I have tuned many "BONE STOCK" Vettes with no problems running 7-9lbs......

Todd157k

iTrader: (5)

I'm not sure. I've been trying to follow the progression (mostly to steal the knowledge) but he's worked on it quite a few times now. I know he didn't make a lot of changes to the VE table when he started. We looked at the fuel trims and they were -1 or 0 across the table.

I got a call last night and he's going to set up a 2-bar SD tune. He's also saying it's the "right" way to do it. Since I'm still a novice at tuning, I'll sit back and shut up.

I'm still going to look at the tune like Jimmy said. See if I can find out what's happening.

Thanks guys. I appreciate your help. I'll post up some numbers when it's done.

Todd157k

iTrader: (5)

well, just in case anyone ever cares what happened (cause I hate searching for threads and finding one with the problem.. but never the solution)

We put the car back on the dyno with a 2 bar SD tune.. but didn't have any boost. One of the hoses was off. We connected it and ran it again.. and again.. and again.. but the intake hose kept blowing off (different hose than the above). We gave up for the day.
That night, at 2:00 in the morning, I realized the reason for the ORIGINAL problem was THE STINKIN HOSE. That's why the MAF wasn't reading. We thought the MAF was screwed up.. but it was doing what it was supposed to do.. read no air. I put the MAF back in, took out the 2 bar SD tune, put in the 1 bar MAF tune and it fired up like a drunkin red-head on Saturday night. Charlie at RPM tuned it up and got over 500 hp (like 511 but erratic) in 110 deg weather. It was so hot, nothing was working right. The car was heated beyond belief, the dyno was torched, the computer was blitzin. We'll get final numbers next week when it's cooler.
Thanks for the help guys. As it turned out, it was simple. Thank God!