I'm running a Weldon B2035A fuel pump feeding methanol to 8 Bosch 160# injectors, controlled by an Accel Gen7 version 6 ECM with wide band O2 in my twin turbo 2.0 Pinto drag car. We ran the previous engine up to 28 lbs boost with a base fuel pressure of 50 psi with no issues. We now plan to start at 30 psi boost and possibly go up as high as 45 lbs boost. The Weldon pump starts dropping off above 80 psi. and requires a lot of amperage to run high pressures, so we've gone to a 16volt battery electrical system to provide ample power to run the pump at higher pressures. However I do not want to run the pump into cavitation at high boost and scatter a very expensive engine. To help resolve this issue, dropping the base pressure back to 40 psi will keep our max fuel pressure near 80 psi at the max boost figure of 45 psi, but it brings questions to mind. Does the Gen 7 compensate for the drop in base fuel pressure to maintain desired AFR's by changing the duty cycle of the injectors, or will the VE map need revision to keep the AFR's where we want them? Also does anybody know if it's possible to set the desired closed loop AFR's on a Gen 7 below 10:1?? Their wideband O2 box goes down to 8:1, so the data is available to the Gen7 ECM, but the software doesn't allow anything below 10:1 as far as I know. Anybody have any information on how this can be accomplished?

 

If you have been adjusting the "fuel rail pressure" value in the configuration screen to coincide with your changes in fuel pressure, then changing it back to match your new fuel pressure, then it will be in the ballpark. The Gen VII does not directly read fuel pressure, but does use the value entered in the configuration screen to adjust the fuel calculations.

I do not know of a way to set the target A/F lower than 10.0 for gas.

 

Thanks, That's what I thought regarding changing the base fuel pressure,and then changing it on the configuration screen. The guy that helps me with the tuning thought it would change the AFR's if we changed the base pressure. I haven't found anyone that knows how to get around the 10:1 AFR limit. I've spoken to the techies at Accel about it, but they don't make the call about a change like that I guess. Guess there aren't enough of us out there running the Gen 7 in the twilight zone to spend the time and money to change the software on this old system. Seems a bit ridiculous to provide a wideband O2 system that is accurate down to 8:1 and then not let the Gen 7 use it below 10:1. At least we have the data now to back up the plug readings!