I installed some FF 640cc injectors on my 1991. Followed the instructions given and tuned the "engine and sequential settings" and dead time to the specifications provided by FF on my Megasquirt.
The car started, but almost immediately the AFR creeped to 20. The car surged and struggled to hold an idle without stalling.
I put the stock injectors back in and set the tune back to how it previously was. The car ran perfect. I don't think I did anything mechanically wrong with installing the 640cc injectors since I undid it and the car runs fine now.
I have uploaded my tune i used. I would appreciate any feedback and advice. I likely did something wrong with the tune.
Thanks
As a side note, I finally ordered my FM turbo kit. I'm excited to get to work on it and finally have fun with boost.

 

Send those Ff640's to me, should fix the issue 😎

 

The instructions also say to be prepared to fully tune your car with the new injectors. The voltage correction for the 640s was entered as .200, not .144 as the instructions say.

I'd also suggest you fix your MAT air density table, use TPS based AE, include AFR target in fuel calc, and find out why your idle valve needs more duty to run than it does to crank.

 

Thank you!