those of you running maft and 550's..

[hottscennessey]

did anyone have trouble setting the base for your 550's on your maft? I'm monitoring with a wideband and it seems like whatever i set it at, the car runs realllly lean, and then goes to 14.7 A/f's (where it is supposed to be). The thing is, I'll get really crappy throttle response on the 550 settings? Is this weird or normal? I just dont want to screw anything up by putting in the wrong base setting. If anyone could chime it i'd appreciate it.:1zhelp:

 

[malloynx]

try the 440 setting. also you need to watch the vf output to see what exactly the TCCS is doing.

one cool thing with the pro is that you can monitor the vf in real time..

 

[hottscennessey]

thanks malloy, I noticed that the 440 setting worked nicely, but i didnt know if this was advisable.

 

[IHI-RHC7]

The only way you can tune for driveability when the stock ecu is in the car is by Vf.
The TCCS will ALWAYS pull fuel to stoich unless it's in open loop mode. So you moniter Vf, and get it to where the Vf is always 2.5 or 2.25 (depending on year of ecu) if you do that, then when Vf goes to 0 Volts, you know that the car is in closed loop mode, and you can do what you wish with the AFR and a wideband.

The only way you can think that you're tuning under normal driving conditions is if you have completely maxxed out the Vf one way or another, and then you start seeing changes on the wideband. Then the TCCS figures out that it can't bring the mixture to stoich, and you get a code.
I hope that helps.
-Jake

 

[hottscennessey]

Thanks a lot IHI. Looks like i have another investment (so i can monitor Vf). Is there any other way to do this other than with a voltometer (sp)? and do you happen to know off the top of your head if you keep a pre89 ECU @ 2.5 or 2.25?

 

[IHI-RHC7]

Ours is 2.25

 

[isnms]

hot - what wideband are you running?
the zeitronic zt-2 has a user input that you can use to monitor VF

 

[hottscennessey]

helll yess
I run the ZT-2. Thats perfect. I didnt even think about that. Now where could i connect it to for that reading??? (any ECU wires would be PERFECT seeing as the glove box it out and thats where the ZT-2 is.)

 

[isnms]

did you get the display unit too? did you get the their boost sensor too?
if yes, the read here: http://www.zeitronix.com/questions/Zt-2questions.htm
Use a two position switch
connect ZT2 Boost Input (Orange wire) to common
connect Boost Sensor input from sensor (Green wire) to one side will give you normal boost display
connect either ZT2 Ground (Brown wire) to other side will show VF on the display if you used VF as your user input

see installation instructions here
http://www.supramania.com/forums/showthread.php?t=100

edit: if you did not get their boost sensor then just wire in the display to show vf, that is if you got the display.

 

[hottscennessey]

hmm, i didnt get the boost sensor or the display unit.

 

[hottscennessey]

soo i feel dumb when i look at those instructions, will i get the readings with the user input by connecting the ZT-2 user wire to the VF wire on the ECU, or will It have the wrong ground or something? Blah

 

[hottscennessey]

so i hooked it up to the user. I'm so confused. I adjust and adjust, but nothing seems right with the VF's. I cannot get a constant voltage. The voltage goes up and down. It sits at 1.8 for 20 seconds, goes up to 3.4 for 20 and goes back down. It never hits 2, no matter how i adjust it. I've gotta be doing something wrong.

What are the VF's supposed to do at Idle?

 

[isnms]

The 1.25 volts or 3.75 volts is considered normal with 2.5 volts considered optimal.

http://alflash.narod.ru/vf1.htm and somewhere on autoshop101.com too.

~2.5 is what you should shoot for at idle but don't start worrying if it swings either way a little bit.
now if your 0v or 5v at idle worry

for zt2 to monitor vf:
you need to connect zt2 Blue (user input) to mkiii gray pin T7-8 (vf) on a 91 wiring harness

since you don't have the display you'll need to monitor it with your laptop, or
you could connect a digital multimeter: red to vf (t7-8) and black to ground (t6-13)

 

[hottscennessey]

okay cool, i did it correctly then. Thanks for all the help isnms.

 

[hottscennessey]

Here is a Zeitronix log (compressed) from cruising around the neighborhood. Included is the Vf signal. I noticed in some places the Vf was 0 volts, i dont know if this was normal or what. Towards the end i hit fuel cut pretty badly. when (throttle possition, rpm?) should i see the signal go to 0 volts and the car will run off a map? Something doesnt seem right to me, any input?

 

[isnms]

to me,
your idle and cruise look ok
the section position#13351-14625 look ok too.
yes vf is suppose to drop to 0 on hard acceleration and af is suppose to jump to 21 when let off throttle after hard acceleration.
however in this section you are not really accelerating real hard, max of about 3000 rpm.

it looks like your are a bit lean. what a/f are you shooting for? 11.5-12 is safe 12.5 is optimum power. on your hard acceleration you are still up in the 13-15 af.

try to give us some cut samples. you can export out sections with starting datapoint and end datapoint.
give us sections of : operating temp idle, cruise and hard acceleration through all gears.

hopefully someone else will chime in too

 

[hottscennessey]

I'm shooting for 11.5's, right now I'm on the 440's setting with 550's. I have a SAFC installed for all the WOT tuning. I'm just trying to get a good base and idle setting.

I'll go out and get some logs of operating temp idle, first things first.

 

[hottscennessey]

This log was at operating temperature, on the 440's setting with all other knobs zeroed, and the SAFC initialized.

EDIT: I just looked back at this log and noticed that the voltage is now jumping from between ~2.25 (where it should be) and ~1, where before it would jump from ~3.75 and ~1.

 

[hottscennessey]

I dont get it, after noticing that the volatge was around 2.25, i went back to the car, started it up, and all of a sudden the voltage was at 5 and the car ran like crap. after changing nothing at all. I'm really getting pissed off.

 

[isnms]

haven't check you last file yet, just wanted to ask
when was the last time you pulled the efi fuse, or disconnected power to ecu? from the link i posted above

...For the ECM to relearn the value, the vehicle must be driven in closed-loop, feedback operation for a certain amount of time...it may take up to 20 minutes for strategy to be re-learned...

edit: just some more thoughts.
it is learning during closed-loop operation. so just avoid excessive open-loop modes for the first ~20min and should be good to go.

closed-loop feedback operation, such as during warm engine idle or during steady cruising i'd say at different rpm levels
open-loop modes of operation such as cold engine start, acceleration, or deceleration