Fast accel problem
383 SBC using Fitech 30003
runs and drives fine, using an HEI distributor 34 degrees total timing. Not using timing control from Fitech
If you're in park idling and try to snap the throttle it bogs and blows flames out the throttle body
If you try to take off hard from a stop it bogs and spits ( sounds like it blowing flames out the throttle body )
If your cruising and try to accelerate hard it bogs
I tried playing with the accel settings BUT the computer keeps putting the old settings back.
Yes i send to the ecu after every adjustment.
I'm very aggravated, i need some advice.
First make sure your "calibration unlock" is set to disable.
Likely your tune is off and running rich already, then Accel pump and boom.
Look at your AFR learn while at idle and at operating temp. I would bet it is -35% and the trim is still trying to pull fuel. If the case, your base tune is the issue, not Accel.
Hi Austin, I am having the same issue with hesitation when starting from a stop at temperature, and yes, my AFR Learn is at -35%, give or take a couple decimal points. That said, I adjusted the dfco return fuel up and it actually got worse and stalled a couple times. Then I tried adjusting it down and the hesitation didn’t get better. I’m nervous about making big swing adjustments, what’s your thoughts?
in regards to the -35% AFR learn, you say the tune is off, any pointers on where to look or begin? I’m going to do son data logging and will post logs in here shortly.
TIA
Update: Data Logs
https://www.dropbox.com/scl/fo/0hoxoio581fr91jhu73hj/h?dl=0&rlkey=sxf2yuhuf2lmrry6xb790uam1.
Ok, here is something everyone should check if they are having hesitation, sputtering, etc. on acceleration after slowing and or upon acceleration after coming to a complete stop and are running an ignition system WITH a distributor but without points.
Check the voltage on the positive terminal of your coil with the engine running. If you have a ballast resistor the voltage could be reduced by the ballast resistor to as low as 5v which will affect the output of the coil and not giving you the spark you need and cause hesitation when accelerating from a stop or after slowing, this was my problem.
The ballast resistor is there to reduce the voltage when the car is running to reduce the wear and lengthen the life of the coil and points. But if you’ve removed the points and installed a Petronix style electronic module then you really don’t need the ballast resistor.
I learned this by watching an episode of Roadkill and removed mine, hesitation gone. Engine is running better than it ever has now.
I hope this helps someone out there who is frustrated and has tried everything else.
Have a blessed day!!