Tuning, MAFT, airflow drop off? KPT4321?

jfdid · 07-10-2004, 12:16 PM

Ok guys, so I've been tuning and tuning and tuning. here's a log of mine from recently. A big problem I have is, when I'm accelerating, it seems to bog and chuck at a certain point in airflow(I haven't figured it out yet). Then I look at my log and it looks like below...WOT, O2's look good, and then bam---the airflow signal from the MAFT drops after 4800 RPM...

I'm assuming kpt4321 can help me with this question: if my "MID" knob is set really rich, and the WOT knob is set really lean, will that cause the MAFT to make an airflow output like below? Rising, then falls down, then rising again?

My next question, how could I be knocking if I'm at .96 Volts? I know you can't tune of O2's but this should give me an idea?

0.02V 38° 17.3% 69.2Hz 1.54ms 2531 0
0.02V 38° 17.6% 75.5Hz 1.54ms 2469 0
0.02V 38° 19.6% 88.1Hz 1.79ms 2469 0
0.02V 38° 21.6% 106.9Hz 2.30ms 2469 0
0.06V 37° 25.9% 125.8Hz 2.82ms 2469 0
0.04V 35° 27.8% 157.3Hz 3.33ms 2469 0
0.16V 35° 35.3% 207.6Hz 3.84ms 2563 0
0.88V 33° 36.9% 232.7Hz 4.10ms 2594 0
0.92V 32° 40.0% 264.2Hz 4.61ms 2688 0
0.94V 32° 42.0% 289.3Hz 4.86ms 2781 0
0.94V 32° 42.0% 320.8Hz 5.12ms 2875 0
0.94V 31° 43.9% 352.2Hz 5.38ms 2969 0
0.96V 31° 54.5% 415.1Hz 5.63ms 3094 0
0.96V 30° 59.6% 459.2Hz 6.40ms 3188 0
0.96V 29° 63.9% 503.2Hz 6.66ms 3313 0
0.96V 28° 63.9% 578.7Hz 7.68ms 3438 0
0.98V 26° 65.5% 679.3Hz 8.96ms 3625 1
0.98V 25° 78.0% 792.5Hz 10.75ms 3781 0
0.98V 25° 86.3% 981.2Hz 12.54ms 4031 0
0.98V 22° 91.4% 1044.1Hz 12.54ms 4313 0
0.96V 22° 96.9% 1037.9Hz 11.78ms 4594 14
0.94V 14° 97.3% 1000.1Hz 10.75ms 4813 41
0.92V 12° 97.3% 975.0Hz 9.47ms 5219 43
0.88V 15° 97.3% 880.6Hz 8.19ms 5500 43
0.10V 16° 97.3% 824.0Hz 7.68ms 5781 43
0.02V 18° 96.9% 849.2Hz 7.42ms 5969 43
0.02V 19° 95.3% 868.0Hz 7.68ms 6125 43
0.06V 19° 12.5% 647.9Hz 1.79ms 6125 39
0.08V 33° 11.0% 69.2Hz 1.28ms 5406 9
0.43V 43° 11.0% 31.5Hz 1.28ms 4813 0

kpt4321 · 07-10-2004, 05:00 PM

http://www.fullthrottletech.com/foru...read.php?t=494

Why is the WOT knob set really lean? It looks BAD.

You need to watch the MAFT box to see when the car is switching to the WOT knob's position. That might be it.

Either way, RICHEN THE WOT KNOB UP! You must be REALLY lean...

The car is going REALLY lean when you hit around 4800-5000 rpm; look at the O2 voltage, it basically goes to zero! That knock is probably real knock, which is not good for an engine...

Trctnless · 07-11-2004, 06:31 AM

Yikes...I'm no pro but have learned alot from KPT4321

'THe WOT knob is Really Lean' so I'd agree your way lean

Which would explain why your getting very low air readings up top. right?
I'd zero it out and start over Tuning the BASE with your STLF&LTFT's
then tune your WOT (conservativley!)

GSX4LIFE · 07-11-2004, 10:48 AM

Your WOT signal should not be WAY lean. If you already have the base set to the injectors(global) then at way lean on the WOT your taking out an additional 20, 25, 30%. Your not giving the car any fuel to work with. And like KPT said, its most likely knocking, which is making the ECU pull timing like a MOFO.

Here is a trick I found with my MAFT. I set it for a 3.5" sensor, even though I have a 3" sensor. I then set BASE to position 8(750cc injcs., I think.. I have 780s) This actually made my idle lean. So I have IDLE set at position 4, or 20% RICH. My MID is set to 2 positions to the left(cant remember the letter) or 10% lean. And WOT is also set 2 positions(10%) lean.

I also have some very minimal settings with my SAFC. Not much at all. Just a little to clean things up.

Now all this said, my car is the best running MAFT car I have ever seen. It gets 25mpg+. I have been running 20psi on 91 piss water. I dont have a dyno, but ask anybody that has been in it at full boost, on race gas(people like RDRKT). The car is making 500awhp.