 Fuel Pump Cutoff For Carbs |
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| Spoke |
 Jul 13 2015, 08:57 PM
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#1
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Jerry  Group: Members Posts: 6,986 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None 
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I'm preparing to install a 2056 dual Weber carb engine in my car and was thinking about how to control the fuel pump. I'll use the existing FI fuel pump relay as done many times before by grounding the appropriate pin on the FI ECU connector to energize the relay with ignition on.
I want to add a safety feature to power the fuel pump only when the engine is running. This is done with all FI systems in case of accident so the fuel pump doesn't keep pumping if the engine has stopped. I want the same functionality with carbs. I'm designing a PCB to power the fuel pump like DJET systems do: Turn the key on and the fuel pump charges the system for 2 seconds then turns off. When the engine starts turning, the fuel pump will run. I forsee 4 wires: GND: picked up on a chassis lug near the relay board 12V switched: Picked up on the FI ECU socket Relay: Picket up on the FI ECU socket Coil Neg: This goes to the tach as well. The coil negative would be the signal to indicate engine running. Should I consider any other functionality of the fuel pump controller? Anyone interested in a PCB like this? Does a 2 second precharge do anything for a carbed engine? I could see if the carb bowls were not full but other than that, not sure a precharge does anything. |
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| SLITS |
Jul 13 2015, 09:45 PM
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None  |
Mallory (Mr. Gasket) used to make a switch that works via oil pressure. It had two contacts, NO and NC. I wired a fuel pump to it so it would cut off the pump with loss of oil pressure.
Fitting is 1/8" NPT, which would thread into the oil pressure hole on the top of the case, but you would loose your oil light unless you used a hose and tee to run all the switches. |
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| SirAndy |
Jul 13 2015, 09:51 PM
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#3
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Resident German Group: Admin Posts: 41,669 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(SLITS @ Jul 13 2015, 08:45 PM)  Mallory (Mr. Gasket) used to make a switch that works via oil pressure. It had two contacts, NO and NC. I wired a fuel pump to it so it would cut off the pump with loss of oil pressure. Fitting is 1/8" NPT, which would thread into the oil pressure hole on the top of the case, but you would loose your oil light unless you used a hose and tee to run all the switches. (IMG:style_emoticons/default/agree.gif) The oil pressure idiot light is a on/off switch. You should be able to use that to control the relay ... (IMG:style_emoticons/default/idea.gif) |
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Posts in this topic
Spoke Fuel Pump Cutoff For Carbs Jul 13 2015, 08:57 PM
ejm Get a fuel pump relay for an early fuel injected V... Jul 13 2015, 09:14 PM
Mark Henry
Get a fuel pump relay for an early fuel injected ... Jul 14 2015, 11:36 AM Mike Bellis Get an inertia switch for a collision cut off. Jul 13 2015, 09:59 PM stugray What you are looking for is a pulse detector circu... Jul 13 2015, 10:45 PM Spoke
What you are looking for is a pulse detector circ... Jul 14 2015, 05:00 PM stugray
The engine has Pertronix Ignitor so it's a cl... Jul 14 2015, 06:56 PM Spoke
Simplest would be to just have a RC circuit that ... Jul 17 2015, 12:11 AM jcd914 VW/Audi early 80s CIS fuel pump relays used tach s... Jul 14 2015, 01:21 AM rgolia Jerry,
When you figure it out count me in. Jul 14 2015, 11:19 AM Valy I agree. I think running a fuel pump without an au... Jul 14 2015, 04:37 PM jcd914 The tach signal passes thru the engine compartment... Jul 14 2015, 06:51 PM stugray First comment is make sure your design can handle ... Jul 17 2015, 01:20 AM jt914-6 http://www.summitracing.com/parts/sum-890145
This ... Jul 17 2015, 04:02 PM stugray
http://www.summitracing.com/parts/sum-890145
This... Jul 17 2015, 04:34 PM andys
http://www.summitracing.com/parts/sum-890145
This... Aug 8 2015, 12:56 PM Spoke Here's a circuit with a 555. Simpler than the ... Jul 17 2015, 10:57 PM Valy And still, my single relay circuit does the same j... Jul 17 2015, 11:12 PM Mark Henry
And still, my single relay circuit does the same ... Jul 18 2015, 06:44 AM John Jentz
And still, my single relay circuit does the same... Jul 18 2015, 08:33 AM Spoke
Sometimes the challenge of reinventing the wheel ... Aug 30 2015, 08:26 AM Spoke
And still, my single relay circuit does the same... Jul 18 2015, 09:54 AM euro911 ... Keep in mind that I am an engineer and it... Jul 18 2015, 11:24 PM porschetub
And still, my single relay circuit does the same... Aug 8 2015, 10:59 PM Valy You're not true to your signature: "CSOB ... Jul 18 2015, 11:06 PM Spoke
You're not true to your signature: "CSOB... Aug 8 2015, 06:29 AM Spoke Here's a first cut at the PCB and the FI plug.... Jul 19 2015, 08:57 AM Spoke Here's a simpler circuit which interfaces to t... Jul 19 2015, 04:17 PM Spoke Here's the layout of the oil pressure fuel-pum... Jul 19 2015, 09:51 PM Spoke Got the boards back. Gotta order a few parts then ... Aug 7 2015, 09:02 PM euro911 Oh, when you said they were going to be really tin... Aug 7 2015, 09:22 PM Spoke
Oh, when you said they were going to be really ti... Aug 8 2015, 06:26 AM Harpo Very nice there Jerry. I would be interested in o... Aug 8 2015, 12:13 PM mepstein BJ's 6 conversion caught fire when the fuel pu... Aug 9 2015, 04:54 AM SKL1 Got the Ford inertia switches for both my cars- in... Aug 29 2015, 10:06 PM |
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