Fuel check valve and the 3port fuel pump |
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Fuel check valve and the 3port fuel pump |
brant |
Sep 10 2016, 07:54 AM
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#1
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914 Wizard Group: Members Posts: 11,625 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
I think there must be a check valve built into the 3 port djet pump
I believe mine is not working (Hard starting symptoms) Has anyone pulled theirs apart? Pictures or a thread? I'm also wondering if adding an in line check valve would work? |
brant |
Sep 22 2016, 11:40 AM
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#2
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914 Wizard Group: Members Posts: 11,625 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
So Brad Anders website indicates their is a check valve in the fuel pump and that there have been instances of them failing...
unfortunately the URL's on his page are not working: Fuel Pump •Function: Supplies fuel to the injectors and cold start valve. •Failure Modes ◦No pressure/inoperative: Can be due to electrical or mechanical failure. The engine will not run in this condition. See the URL below for a test procedure. ◦Improper fuel line hookup: Very odd problems in maintaining pressure, with odd drivability problems. Check the factory workshop manual for the correct hookup. ◦Clogged return line: I had this happen when I converted back from carburetors, my return line was clogged at the tank. High fuel pressure and rich, possible gas contamination of oil. If you can't regulate the pressure, this may be your problem. ◦Failed Check Valve: The check valve keeps the pressure to the injectors and CSV up after the fuel pump is shut off to prevent vapor voids from forming and speed up starting. A failed check valve may cause some hot starting problems. There has been one report of a failed check valve causing the fuel pump to return all fuel to the tank, with no supply to the injectors. See the URL below for a test procedure. •Notes: Detailed procedures on checking the fuel pump are documented in the Factory Workshop Manual. The electrical plug, contacts, and boot are often in poor condition due to exposure to heat, battery acid, and the environment. Contact failures are a common cause of a sudden shut-off of your car while driving. You should hear the fuel pump run for 1.5 seconds after turning the key to the "on" position. If you don't hear the pump run, check the fuel pump relay on the relay board, and the connection plug to the fuel pump. I keep a cheap Radio Shack multi-meter in my car just for this problem. •More: There is an excellent reference on debugging fuel pump problems at the URL below: http://www.914fan.net/fuelpump.html I also have created a series of flow charts for diagnosing the fuel pump circuit and relays: http://members.rennlist.com/pbanders/FPChecklist.htm |
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