Quick Fuel QFI Issues

[stroked_c10]

I am currently trying to get the QFI set-up on my 383 SBC to perform and unfortunately there is very little information available, I assume because the set-up is new to the market. At the same time, the information available for Quick Fuel is lacking (IMHO). This is my first adaptive learning install, but it has been far from easy to get running appropriately.



So here is what is happening...Installed the QFI setup and it has not run well since I began. I have driven it extensively to let the self tuning work. As it stands, the nagging problem is that between 2000 and 2500 (during cruise), it gets excessively lean (16-17 on the AFR) sometimes. At other times, it tracks right along at 13.5 or so. From takeoff, sometimes, it jumps right off the line and then falls right on its face. Same for acceleration. During these situations, it seems to be RPM hunting and as I monitor the AFR, it is going excessively lean and causing surging. A blip of the throttle or pushing it over 2500 RPM and it settles down to an acceptable AFR. It is very inconsistent and very frustrating. It is definitely not cool cruising down the street. I cannot say what it does at higher RPM because i am afraid to push it up there. When it started, I thought this was part of the learning process but it has been way too long for that to be the case.


My combo is a 1971 Chevy C10 with a mild 383. It has a Summit air gap dual plane, mild cam, and factory iron heads. It is nothing hot, but it was in the truck when i bought it. It has long tube headers and true duals. I installed the QFI exactly as in the install manual, my O2 sensor is about 6 inches back from the primary tubes in the reducer. The fuel system is a Tanks Inc tank under the bed with an in tank pump and new lines to the QFI regulator on the firewall. After talking to QFT tech, I routed the fuel to the throttle body first and the regulator next, and it keeps a steady 45 PSI.

When I first started driving, there was lots of sputtering and stalling, so QFT Tech told me to max out the settings for accel. The owners manual doesn't tell what any of the numbers mean, only the range for setting them. I have since backed that off significantly, from 90 to 20 and it is better, but I am concerned of getting too low. Once again, there is no explanation of what any of these settings or numbers are relative to, so I am not sure what % or value I am really working with and I don't want to damage it in the process. I have been backing it off based on another thread I read that too much fuel will consistently make the computer pull fuel and keeps the engine lean. The fuel mileage is terrible BTW.

I have trolled other forums and chased other people's problems with no success (wrapped wires with tin foil in case of RFI, replaced all the exhaust gaskets in case of leaks). Any help is appreciated. I am very dissatisfied at this point but hate to speak ill of a new product, but this stuff is expensive and definitely has not been user friendly.

[MonzaRacer]

OK the accel. Setting is basically a tau setting, it allows for engines needs, wall wetting of intake, etc.
With out seeing the instructions it would be hard to completely understand issues. Most learning systems learn from O2 readings, and cruise map readings.
Most cars are constantly adjusting fuel injector pulse widths, timing, and some even change fuel pressure.

[Jerinp]

Did you ever figure this out? I’m having the same issues with mine !