LQ4 into a 3rd Gen/1972 Nova by frojoe

2 minute(s) of a 891 minute read

I'm using an Edelbrock boost-referenced adjustable fuel pressure regulator, -10AN straight cut o-ring threads on the input and output, -6AN return port... so flow restriction in the unit itself shouldn't be an issue.

To save myself explaining it via typing... in the below picture my current system is the top diagram, and the bottom diagram was what I had before. The 3rd port is blocked off on my current setup, like the top diagram..

11-2-2018

Here are screencaps of that same above log & time window that LSswap quoted, but I've included injector pulse width, injector duty cycle, and fuel learn % for reference. I'm not expecting these to help get me any obvious solutions, but just to help you guys get the same visibility of what I'm seeing. It really looks like the fuel pressure is dropping off first and then everything is compensating [with a bit of lag] from there... to me it seems to point to a mechanical fuel flow issue and not a tuning one.

This is timestamp 190 seconds, the instant fuel pressure stops remaining constant due to constant MAP aka throttle position...

This is timestamp 194 seconds, when fuel flow ends its slow decline and afterwards starts to drop off FAST...

This is timestamp 197 seconds, when fuel pressure is at its lowest, compensation/learn is highest, and AFR is highest before I back off the throttle...