Lean/rich stumble bog solutions
I see high IAC steps when at idle and some surging. Try giving it a little more idle screw.
Couple of things I noticed on these last logs.....
Your IAC steps are very high at idle. The lowest I saw it go was 30. You want to be around 5-15.
I see your lean tip in on throttle. What do you have your Accell 170 set to?
Also, according to your trims, the computer is adding fuel to reach your target AFR. What cam setting are you using?
I adjusted IAC again. Now it's 6-12, however it above 20 when idling gear selected. Is this ok or should it be same also on drive?
My accel is +50 and cam 1. Vacuum 17 on idle.
Quote from VintageSpeed on May 11, 2019, 1:33 pmI adjusted IAC again. Now it's 6-12, however it above 20 when idling gear selected. Is this ok or should it be same also on drive?
My accel is +50 and cam 1. Vacuum 17 on idle.
Yes, IAC goes up when you put in gear. This is why we typically only worry about IAC steps at idle nd at operating temperature.
Today I had the car on ramps and my friend welded the O2 bung in place instead of the hose clamp thing Fitech supplies. I was hoping that might cause some issue. I did a complete relearn after that but did not get any positive effect on the hesitation issue.
However when I was adjusting the IAC steps again couple of days ago I noticed this: I have a pushrod operated throttle since this is a 1963 car. Fitech does not seem to like this since the linkage is binding just a little bit. When I pull the linkage both throttle bodies open 1:1.
What do you think. Can such a small movement cause tip-in lean condition? Check the video.
This is part of my hang up with their 2x4 system. You have a total of 4 shafts connect by a multi piece linkage. If your manifold is not an open plenum, the MAP and TPS will add fuel to based on the front TB. Back TB could have different air flow, causing issues. Much different than a dual carb setup. Plus a slight change in throttle angle creates a large change in airflow.
Hey guys, im new here. Reading this post is exactly the issue im having with my 2x4 setup, starting to really frustrate me. Ive tried everything above, still feels like it needs more accel pump but now maxed out. Have you guys had any joy since the last post?
Not really. I adjusted all butterfly valves and linkages. Made a new linkage for throttle pedal pushrod and relearned the whole thing.
Only effects I saw was when I leaned the idle AFR from 13.7 to 14.7 and took AFR neg trim to minimum so the ECU can't trim fuel off so much. The hesitation is still there and it happens only after decel. The problem is transition fuel but unfortunately there are no clear instructions how to adjust that in Fitech.
Is there any way to dump fuel in during decel?
I think that is what the "tipout" values are for but I didn't see any change when I played with them.