[dan50]

Is anyone able to review my tune (attached)? I will figure out how to datalog this weekend (I hope) but for now here's a description of what's going on.

I went from MS to A9L / Quarterhorse / MAF. I'm having surging issues at part throttle and what feels like spark blow-out when I put my foot on the gas - the engine will wake up after a few seconds and then it falls on it's face in the higher rpm range. The car also runs super hot and the temp keeps creeping up no matter if it's idling or going 70 mph on the highway. I'm thinking that there's too much advance or I'm running way lean. Although I haven't messed with timing, only fuel and the MAF function, so I'm thinking lean. Car ran fine from a temperature perspective prior to the MAF / A9L install. It's a 93 Mustang LX 5.0, A9L, Quarterhorse, stock short block, TFS 11R 190 heads / roller rockers / FTI cam, TFS intake, 36 # Trick Flow (Accel) injectors, new PMAS HPX-E maf sensor in their 85mm tube. Here are the steps that I took -

1) I created the MAF flow curve in PMAS's Excel spreadsheet and then used the BE MAF Fitting Tool to enter the values into BE . I kept the 0v row and matched the 15.998v rows to the values in the 5v rows.
2) I set the injector high slope and low slope to 38.557 (injector datasheet is here).
3) I set the injector breakpoint to 1.284 x e-5 lbs / revolution.
4) I changed the FN348 Crank PW ECT Modifier per Delphia's A9L2 post instructions based on the formula 19/(new injector size) * (new engine size)/302=0.xxx, using 302 as the new engine size and 36 as the new injector size to get 0.527777778.
5) I entered the injector offset from here).
6) I shifted the mass flow to a lower range to avoid the 2350 # / hr cutoff by dividing by the entire curve by 2.
7) I modified the load calculation by dividing the CID size of the engine in BE by 2.
#8) I divided the fuel injector sizing by 2 to inject more fuel since I reduced the MAF flow curve by 2.
9) I divided the injector breakpoint by 2 to return the fuel tweaking to normal.
10) I divided FKARC1 and FKARCH by 2 since I had divided the CID by 2.

I downloaded this BIN file to all slots in the QH per instructions I found on EECtuning.org so that the fuel pump doesn't run all the time. And it drives like crap lol. Any thoughts on what I should look at?

Thanks!
Dan

[Paulie]

I took a quick look at your tune. Do you have a wide band? Can you post a log? Have you tried adjusting the MAF to richen it up?
I would not have picked that MAF with your combo. You will not get anywhere near the upper limits of that MAF and you are giving up resolution at the lower flow rates where you will spend the majority of your time driving, unless this is a strip only car. I have a PMAS MAF and I had to make pretty significant adjustments to get it close. The manufacturers sheet is just a rough starting point. What is in front of and behind the MAF has a significant effect on how it reads.