Sounds not too shabby. I noticed that the needle on the inline gauge at the carb didn't deflect all that much when you goosed it but if the ECU is handling the fuel delivery then it would be handling the sensing of a change in fuel demand and responding to that increase/decrease accordingly. Because the increase in fuel delivered to the throttle body is only brief, there may not be enough time for the ECU to receive a change in the throttle position from the IAC (Idle Acceleration Controller) and respond to it
By way of example, the screen on the programmer/monitor for my own FI unit shows the various subroutines and programs that it has written to its E-Prom. One of these has a subroutine that displays a feature called "Large Gauges" and shows a list of inputs that can be displayed as digital readouts. There is a four item limit but if a viewer might want to see a specific set of items all they do is scroll down to the item they want and highlight it as being part of the list of items to show. On mine I have the idle rate in RPM's and the IAC response rate listed as to be shown and that lets me watch how quick the idle drops as the motor warms up. For my own FI unit, the IAC reading has to fall below 9 with the motor temp at the point the thermostat opens to be acceptable and to get it there I had to do some serious tweaking to the idle stop screw because it had come totally unadjusted; it was completely unscrewed with no tension on the spring, from the factory, and the installation literature had not bothered to mention that wee fact.
Where I am headed with all this is that, were your screen to be showing the IAC reading and you blipped the throttle, the value of the reading ought to rise quickly and then just as quickly drop back to, well, call it "rest" or "off". You wouldn't necessarily see the fuel pressure shift but the increase in the IAC value would be the ECU taking note of the increase in the fuel delivery and raising the idle rate to compensate for it.
Is Holley still believing that your problem is fuel delivery related? If it idles okay but dies at speed or under load, Have you, at this point, done a full fuel system investigation; starting at the tank with the pickup and checking everything between the tank and the FI? Kind of wondering here if the system is Return, meaning it has a full line running back from the FI to the return inlet on the tank, or returnless, meaning that either the electric pump in the tank has the ability to monitor and maintain the fuel pressure at exactly what the engine needs so no excess fuel to be returned back to the tank, or if an inline pump, it has a built in regulator, like the Holley Pumps, one version of which I happen to have, that diverts excess fuel right at the pump and immediately sends it back to the tank via a dedicated return line plumbed directly into the pump. No line from the GI unit required. Is there an line filter located at the pump? Are lines large enough to handle the volume of fuel that the system is delivering.
All of this is highly interesting to me simply because at some point in the immediate future I will have to replumb the fuel delivery system in my van and the tank is supposed to be getting either an in tank pump, or possibly the external in line with the built in regulator My big sticking point is geography, the tank has very little open top area available to drill the hole for the new in tank unit. Decisions, decisions.
Nick
Nick
