Quote Originally Posted by 34_40 View Post
Thanks for that last update Roger. It amazes me also when you talk of mili-seconds and the tiny changes your making to them. I am also confused by the "batch fire" principle.. I guess I have some more efi educatin' to survive.. 8-)
One of the tid-bits that my Edelbrock tech shared last time we talked, trying to understand my starting woes (before I focused on the battery) he mentioned to me that one of the features of their system is that on initial crank the injectors are firing "batch mode", meaning that all eight injectors fire together rather than triggering sequentially as each cylinder reaches it's "normal" point in the timing. If the engine fails to light during that initial starter crank, in each subsequent crank (without powering down the ECU, "start" back to "on", then to "start" again) the ECU reverts to sequential mode, firing each injector individually. With my PB start system I hit the "start" button, which closes a momentary relay for the starter, but also "sets" the "on" relay so that as I let off of "start" it "seals in" for "on", maintaining power to the ECU and coil to run. However, if it fails to start I have to press "start" again to break the seal, powering down the ECU, and then press "start" again to engage the starter in a new start cycle. This means that for me, every "start" attempt is a "first start", and my injectors fire "batch mode" for any start attempt. It makes my crank fuel correction more consistent (no change from batch to sequential), but also much more sensitive to flooding as every cylinder gets an injector pulse at the same time, regardless of piston position. One thing that many people don't know is that the early Ford EFI's, which have eight individual port injectors, fire in batch mode, not sequentially. Sounds goofy, but when you're running at mid to high rpm the difference in injector timing is so very, very small it's really moot for a street application.