FAST VE craziness
05-28-2005, 11:36 PM
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FAST VE craziness I am tuning a friend's car and am finding very high VE numbers in order to find reach my target A/F ratio. I'm seeing 78 at idle and >100 in some part throttle areas. This is with what we are pretty sure are 72# injectors.
What could the problem be? As far as I know, all of the base fuel calc parameters are correct.
We put in a known set of 83# injectors, double checked the MAF and fuel pressure, and retuned the car. Now it wants to idle at 95 VE. The exhaust smells fine and the car idles smooth so I don't think it is a bad O2 or anything like that. If I lower the VE the car goes lean quick and dies around 75 VE.
The FAST calculates fuel from the following, right?
VE
CID
# of cylinders
Injector size
MAP
I have checked them all and it is still running weird. I even loaded a tune from another car to make sure there wasn't some hidden value mucking things up. What is going on?
The car idles at 51 VE when I doubled the CID in the FAST, but I don't want to band-aid the tune like that. Please help.
-Aaron
What could the problem be? As far as I know, all of the base fuel calc parameters are correct.
We put in a known set of 83# injectors, double checked the MAF and fuel pressure, and retuned the car. Now it wants to idle at 95 VE. The exhaust smells fine and the car idles smooth so I don't think it is a bad O2 or anything like that. If I lower the VE the car goes lean quick and dies around 75 VE.
The FAST calculates fuel from the following, right?
VE
CID
# of cylinders
Injector size
MAP
I have checked them all and it is still running weird. I even loaded a tune from another car to make sure there wasn't some hidden value mucking things up. What is going on?
The car idles at 51 VE when I doubled the CID in the FAST, but I don't want to band-aid the tune like that. Please help.
-Aaron
05-29-2005, 12:23 AM
#2
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perhaps you need to increase the pulsewidth voltage adjustment. I wonder if FAST supports this. larger injectors seem to take longer to open (at least my MSD 50's sure do), and thus deliver less fuel. You would increase VE to try to compensate.
05-29-2005, 01:34 PM
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Originally Posted by Draco
perhaps you need to increase the pulsewidth voltage adjustment. I wonder if FAST supports this. larger injectors seem to take longer to open (at least my MSD 50's sure do), and thus deliver less fuel. You would increase VE to try to compensate.
-Aaron
05-29-2005, 05:09 PM
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Originally Posted by Pro Stock John
What is base FP set at?
John, are you going to be at Photos this summer at all? I still have that white caprice, and I plan on putting it into the 11's this summer.
-Aaron
