XFI Problem

[Jeff Rand]

I installed an XFI and I am having a problem. At idle it runs fine with an a/f of about 13.4:1 as soon as I put the car in drive it goes lean (15:1) and stalls when I try to accelerate. If I change the VE numbers to get it to drive; my a/f in park goes rich (10.5:1). I have taken the closed loop out of the equation and increased the ms from .9 to 1.1ms in order to get it to drive.
Jeff

 

[norbs]

That seems about right, my dfi does the same. Bring the closed loop back into the equation, and it will pull fuel in park to lean it back out. Your ve cells are probably off just above idle causing the hesitation, or you have to work the ae enrichment. I am not an xfi specialist so maybe someone else here can give you more input. The throttle follower could set to low also just above idle and your iac postion maybe to high or low to maintain the idle.

 

[Jeff Rand]

That seems about right, my dfi does the same. Bring the closed loop back into the equation, and it will pull fuel in park to lean it back out. Your ve cells are probably off just above idle causing the hesitation, or you have to work the ae enrichment. I am not an xfi specialist so maybe someone else here can give you more input. The throttle follower could set to low also just above idle and your iac postion maybe to high or low to maintain the idle.

Norbs,
The engine does not really hesitate, it dies in drive as soon as you try to give it gas. When I increase the a/f it improves driveability.
Thanks,
Jeff

 

[Otto J]

Jeff,email me the file and let me take a look at it,you will find that the car runs a bit rich in park to keep it idling well in drive.but if you run it in closed loop at idle you may be able to make it cleaner,sometime getting rid of a rolling idle will be a problem then.

 

[Jeff Rand]

Jeff,email me the file and let me take a look at it,you will find that the car runs a bit rich in park to keep it idling well in drive.but if you run it in closed loop at idle you may be able to make it cleaner,sometime getting rid of a rolling idle will be a problem then.

Thanks, I will try to get you the file tonight.
Jeff

 

[HighPSI]

Keep in mind the XFI has variable scaling. You may need to rescale things so it idles in a diferent area in and out of gear.

 

[Jeff Rand]

Keep in mind the XFI has variable scaling. You may need to rescale things so it idles in a diferent area in and out of gear.

Cal.
Thanks for the input. How would I do the rescale?
Jeff

 

[HighPSI]

Left click your mouse over the value you want to change. It will prompt you to enter a new value. I would try and rescale the KPA scale with your kpa in park/neutral as the bottom row and your KPA in gear as the one above. If you have a loose covertor, you may not have much of a change in KPA to do this with.

 

[Jeff Rand]

Cal,
Thanks for the help. I will give it a try today.
Jeff

 

[EightSecV6]

Have you tried adjusting the AE settings? If it goes lean (stalls) only when you hit the gas, you need to increase the enrichment in the AE fuel vs TPS rate and/or AE fuel vs MAP rate. Does it do it at any engine temp.?

 

[Jeff Rand]

Have you tried adjusting the AE settings? If it goes lean (stalls) only when you hit the gas, you need to increase the enrichment in the AE fuel vs TPS rate and/or AE fuel vs MAP rate. Does it do it at any engine temp.?

It goes lean as soon as I put it into gear. It quickly go up in increments up to about 15:1 then it will slowly drop back down to about 13:1 (I can see it adding fuel on the correction to bring it back into range. I have it in closed loop at this point).
Jeff

 

[Mad_Trbo]

It goes lean as soon as I put it into gear. It quickly go up in increments up to about 15:1 then it will slowly drop back down to about 13:1 (I can see it adding fuel on the correction to bring it back into range. I have it in closed loop at this point).
Jeff

I had the same issue when I first installed my FAST.

Open yur VE table and watch it as you shift into drive. I would suspect that as you shift the car into drive the load on the motor increases. Unless you have huge differences between your KPA readings on the vertical axis you should be able to track it the instant you shift into drive. The cell it ends up in when it dies and those to left, right top and bottom I would increase the by say 10-15% just to keep it running and then you should be able to adjust it with the brake on and in drive to an acceptable range. If the car continues to die with the above suggested increase I would continue to increase until you can get it to run in drive.
If your load doesn't change cells when you go into drive, you may need to do as HighPSI suggest and rescale, your KPA readings may be to far apart and aren't allowing enough of a micro management of fuel.

 

[Jeff Rand]

I had the same issue when I first installed my FAST.

Open yur VE table and watch it as you shift into drive. I would suspect that as you shift the car into drive the load on the motor increases. Unless you have huge differences between your KPA readings on the vertical axis you should be able to track it the instant you shift into drive. The cell it ends up in when it dies and those to left, right top and bottom I would increase the by say 10-15% just to keep it running and then you should be able to adjust it with the brake on and in drive to an acceptable range. If the car continues to die with the above suggested increase I would continue to increase until you can get it to run in drive.
If your load doesn't change cells when you go into drive, you may need to do as HighPSI suggest and rescale, your KPA readings may be to far apart and aren't allowing enough of a micro management of fuel.

Thanks for the advice. I was able to get a program that had the VE table rescaled and after some tweaking I got it running.
Jeff

 

[Mad_Trbo]

Thanks for the advice. I was able to get a program that had the VE table rescaled and after some tweaking I got it running.
Jeff

Hey no problem, just curious, can you post what your KPA scale is. I would love to compare to what I have and ask you how driveability is?