MegaSquirt TBI Enrichment Tuning

[qadir03]

I have been trying to tune the accel enrich for a while now and can't seam to get it to work properly. Also what kind of deaccel setting are you guys using. Whenever I get off the throttle after being on boost a cloud of black smoke apears. I have overun kick on and deaccel set to 0%.

 

http://students.washington.edu/qadirz/MegaSquirt/DATALOG%20AIR%20TEMP%20RISE.JPG

 

Here is my datalog: Wideband set at 0V=10AFR 5V=20AFR

http://students.washington.edu/qadirz/Mega...00508071921.xls

 

Here is my MSQ: using MegaSquirt2.25b442

http://students.washington.edu/qadirz/Mega...00508072007.msq

[eeaston]

Accel enrich is one of the trickiest things to set. Mine's still not perfect. One thing that I notice is that your TPS % never goes over 50%. Fix that first.(Tools>Calibrate TPS)

 

Carefully read the Megamanual section about accel enrichment tuning, They explain it better than I can.

 

Also, while tuning you maps, etc. you should turn off EGO correction. Get your maps as close as possible before using closed loop.

[qadir03]

My tps is calibrated correctly, I almost never go above 50% to get the car going. Are you running the TBI or are you MPI. My map is as good as it gets. I've been running MS for over a yr now. I just haven't been able to get the accel as smooth as posible as I can. As for deaccell do you rich out when you get off boost?

[eeaston]

Mine's MPI. Are you running the stock injectors? Alternating or simultaneous?

 

I'm running the -extra code, so things may be a little different.

 

I have mine cut fuel completely on over-run, with a .5 sec delay, KPa<20; TPS < 55; RPM > 1700

 

I get just a tiny rich spike when I drop off the pedal, but no smoke that I've noticed.

 

If your GEGO is going down to 80% then I'd say there's room for improvement in your VE table.

 

Looking at your log where you were blipping the throttle, I notice that maybe only one in 5 or so blips actually triggers your accel enrich. I don't see why, your threshold and bin values are both lower than mine.

 

Your accel values (PW times) are also much higher than mine, particularly the slower values. Mine are 1,4,6,8 at the moment. Like I said, though, mine isn't perfect on accel either.

 

One good way to pinpoint your problem areas is to hit the spacebar anytime you notice the car falter under accel. Then when you look you can quickly pick out these spots and see whether you're rich or lean under accel when you go back and look at the log.

[qadir03]

I am using 2 608cc injectors set at alternating.

I will mess with tuning it more this week. Does anyone here have MegaSquirt with their TBI. Since this is a TBI setup, I believe that the injectors are way too far from the combustion chamber to react fast enough to stop stop feeding fuel when the change in manifold air pressure is so high. That might be causing the rich mixtures after getting of the throttle under boost. What kind of injectors are you using and are you using a wideband?

[eeaston]

I'm running delphi injectors and wideband.

 

What type of injectors are yours, are they stock type? If not you might consider trying two stock secondaries as they have a spray pattern designed for our TBI manifolds. I wonder if you're getting some fuel pooling in your intake at high MAP/long pulsewidth then when you close the throttle it gets drawn into the cylinders as liquid?

 

Any idea why your datalog almost never hits accel enrichment?

[qadir03]

I am running the TBI injectors, I can't tell if they are the secondary or the primary. Do you guys have a way of finding out by part number? These are the list of the injectos I have with part number and where I got them from. Injectors have been flow tested so all the flow rates are accurate.

 

MIRAGE:

L85-2

L25-3

65.5 POUND PER HOUR 688CC@3BAR

 

TREDIA:

B59-2

B59-2

3BAR=76ML

40PSI=72ML

57.9 POUND PER HOUR 608CC@40PSI

 

87 STARION:

J57-3

J57-3

3BAR=122ML

40PSI=116ML

85.3 POUND PER HOUR 896CC@40PSI

 

85 Mirage

B55-3

40PSI=70ML

43 POUND PER HOUR 452CC@40PSI

 

I need to post another log. I had the TPS threshold set at 30V, so that is why no accel enrich is kickin in. Like you said about puddles of fuel, that is what I was thinking of. I think if i set the overrun to cut fuel below 90kpa, tps at 0% and above 2000 rpm that might help.