View Single Post
ClickClickBoom ClickClickBoom is offline
Caveman Hammer Mechanic
ClickClickBoom's Avatar
Join Date: Feb 2009
Location: Boulder Creek CA
Posts: 3,306
Without talking to Dr Porsche, I will bet that the design philosophy is similar to many other 2 pump designs. The first pump is a delivery pump, high volume, low pressure. The second pump is a pressure delivery pump, high pressure, low volume. The reason you are experiencing the symptoms of quitting when you pull the relays is because the rear pump is not working at spec and unplugging the front kills the supply. The lean running on boost points at reduced high pressure fuel and the resulting lean condition. I would suggest plumbing pressure guages after each pump and check outputs against the FSM for your car.

Last edited by ClickClickBoom; 02-23-2009 at 08:59 AM..
Old 02-23-2009, 08:05 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)