Stumble on fast acceleration
1970 BBC 396, cam is
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=444&sb=2
Edelbrock RPM Air Gap
Pertronix HEI not controlled by Fitech
Fitech inline fuel kit installed below tank within 2 feet.
Replaced the temperature sensor once I realized mine was bad.
The car starts, idles and runs ok under gentle acceleration. My problem is a severe stumble on fast acceleration that does not resolve no matter how much adjustment I make to Accel Pump, or Fast Accel inputs. Current settings are Accel Pump 170 = 25.0 and Fast Accel 170 = 50.0
The stumbles I feel are confirmed in the log files as a very lean spike on acceleration followed immediately by a very rich condition.
I installed a pressure gauge at the inlet, behind the filters and fuel pressure is at 55 psi, increases to 60 psi during fast acceleration. I think fuel pressure is ok.
Been trying to get help from Fitech for 2 weeks. Very discouraged by their lack of availability and support.
I have a dashboard log file with some idle time, gentle acceleration, and a few quick acceleration events that clearly shows the problem. Would appreciate a review and any advice.
When you say "behind the filters" do you mean before filters in the fuel flow direction?
The gauge is on the inlet, the filters are between the gauge and the tank.
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Ok, that should be accurate then.
The datalog will be helpful. I prefer a 30 second log at idle only and at temp, at first. Sometimes we can identify issues their. You can post a Dropbox or Cloud link here. At this time we cannot post logs directly to the site. Something we are working on.
When we do longer logs it becomes a lot of data....
Do you have gmail?
That would make it easy.
oh, and thanks!
Message it to me on Facebook. I'm under the same name. Then I will post on the forum.
Quote from Austin DeHaas on November 13, 2018, 11:29 pmMessage it to me on Facebook. I'm under the same name. Then I will post on the forum.
hi
i have same problem
but i increased accel pump to 99 and fast accel to 99 and for dfco return fuel 150
after changing these parameters my car hesitation a lot of better and lower but it is still remains
whats your opinion for me ?
my car is impala 77 L6 250 TH350 2.73 final Drive ratio and stock components .
tnx
Quote from henry.ss on February 15, 2019, 5:16 amQuote from Austin DeHaas on November 13, 2018, 11:29 pmMessage it to me on Facebook. I'm under the same name. Then I will post on the forum.
hi
i have same problem
but i increased accel pump to 99 and fast accel to 99 and for dfco return fuel 150
after changing these parameters my car hesitation a lot of better and lower but it is still remains
whats your opinion for me ?
my car is impala 77 L6 250 TH350 2.73 final Drive ratio and stock components .
tnx
What is your AFR doing when it stumbles?
I have the exact same issue as OP. L31 vortec crate motor with edelbrock performer rpm air gap, 600pa system with fitech inline pump.
Anytime I whack the throttle open, my afr will jump up to 18 then down to 10.5, the motor will bog there for a second and then it comes alive starts pulling hard. The afr generally comes up to 11.5-12 when it clears up. I have adjusted fast accel up to 160 and it is now down to -10. Accgain and acc max have been as high as 160+ down to 100 now. The issue does not change with settings change.
Part throttle driveability is great, and I can roll into the throttle without any issues.
I don't have any data logs because I spent a long time chasing the water temp sensor issue.
Thoughts?