The reason for so many fuel pumps is a mystery to me. The crazy germans who built this car in the first place must have had a reason. I suspect they were running inn enduros and wanted a backup pump system. The two transfer pumps (on top) are used to pick up fuel at each corner of the fuel cell and deliver to the holding tank. Then pump 1 and pump two both pick up fuel from the bottom the bottom and are tied together and run through the red filter to the fuel rail. One of the other problems with this setup is possible back wash through the pumps. They need a one way valve on outlet side which these don't have. There is also the possibility of the FPR restriction as well. I think I will do a volume check to eliminate any possibility of starvation there although I just cant imagine any.l
I really didn't want to disassemble this and start from scratch but it may be the best way.
I'm giving it one last shot next weekend at Summit just running one fuel pump with fuel pressure regulator set at 1 bar. The Zietronix says I am running about 10 to 1 AFR right now. We compared Zietronix readings to wideband on the dyno and they were very close. If the car runs a full session under load and seems to hold pressure I am going to try and drop fuel pressure a bit and check AFR under load on track.
I will update after event.
Pete
