 What the damn hell?!, Was my carb fuel pump really wired like this?? |
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| Optimusglen |
 Dec 9 2016, 08:43 AM
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#1
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Senior Member  Group: Members Posts: 908 Joined: 26-February 16 From: Minneapolis Member No.: 19,709 Region Association: Upper MidWest 
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I've been steadily marching through my project.
http://www.914world.com/bbs2/index.php?showtopic=277349 And I came to the fuel pump. I'm doing an entire new fuel system because of the unknowns and the pursuit of peace-of-mind. Anyway, a few weeks ago I pulled the old low pressure pump (located in the engine bay) and the fuel lines, but had left the wiring. Last night I was under there and decided to see how they wired this thing. There was one yellow wire coming from it, it was outside of the wound loom but otherwise ran alongside it. Crawled inside and found it near the firewall, pulled it out, then moved up to the other end of the tunnel, found it there and pulled it out. Traced it up under the dash only to find... (IMG:http://www.914world.com/bbs2/uploads_offsite/c1.staticflickr.com-19709-1481294601.1.jpg) (IMG:http://www.914world.com/bbs2/uploads_offsite/www.feelsengine.com-19709-1481294602.2.jpg) It's the yellow wire with the tab of masking tape. It's running to the back of a gauge. What gauge you ask? (IMG:http://www.914world.com/bbs2/uploads_offsite/c1.staticflickr.com-19709-1481294602.3.jpg) So now I have to ask myself it was really the yellow wire that I had pulled off the fuel pump. I mean, could this have any possible way to actually power the pump?! |
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| GeorgeRud |
Dec 9 2016, 09:55 AM
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#2
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Advanced Member Group: Members Posts: 3,725 Joined: 27-July 05 From: Chicagoland Member No.: 4,482 Region Association: Upper MidWest |
Fuel pressure gauge on the left. Definitely a previous owner's kluged wiring job. If you're replacing the fuel system, move the fuel pump up front by the steering rack. Porsche actually did this modification in the last years of production with a removable plate in the front firewall.
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| Optimusglen |
Dec 9 2016, 10:00 AM
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#3
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Senior Member Group: Members Posts: 908 Joined: 26-February 16 From: Minneapolis Member No.: 19,709 Region Association: Upper MidWest
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QUOTE(GeorgeRud @ Dec 9 2016, 09:55 AM)  Fuel pressure gauge on the left. Definitely a previous owner's kluged wiring job. If you're replacing the fuel system, move the fuel pump up front by the steering rack. Porsche actually did this modification in the last years of production with a removable plate in the front firewall. Yeah, dealing with previous owners messy wiring hacks is going to be a pain. Fortunately the rest of the wiring looks intact and original. And yes, I actually mounted the new pump and filter in the front trunk, I wanted it away from the elements but also accessible. Not sure what that fuel pressure gauge is wired to... I'll probably yank it though. When I redo all the wiring I'll solder and heat shrink. |
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| Optimusglen |
Dec 9 2016, 11:46 AM
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#4
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Senior Member Group: Members Posts: 908 Joined: 26-February 16 From: Minneapolis Member No.: 19,709 Region Association: Upper MidWest
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Been doing some more research and found that either I mistook that yellow wire as coming from the fuel pump, or someone hooked that up in error. Still not sure how they powered the pump, I'll have to dig into it more next time I'm in the garage.
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| zambezi |
Dec 9 2016, 11:47 AM
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#5
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Senior Member Group: Members Posts: 711 Joined: 14-April 08 From: Lafayette, LA Member No.: 8,920 Region Association: South East States |
Looks like the yellow wire is on the ground terminal
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| IronHillRestorations |
Dec 9 2016, 12:54 PM
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#6
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I. I. R. C. Group: Members Posts: 6,719 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None
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I had a car in here recently that had the fuel pump relocated up front, and they ran the power through the unused fuel line to the coil.
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| anderssj |
Dec 9 2016, 03:58 PM
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#7
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Dog is my copilot... Group: Members Posts: 1,656 Joined: 28-January 03 From: VA Member No.: 207 Region Association: MidAtlantic Region
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?????
The only thing I've seen remotely resembling that set-up is when an oil pressure switch/warning light is used to control the fuel pump on carb'ed car. No oil pressure = no current to the pump. The theory is that the oil pressure switch functions as a "safety switch" cutting off power to the fuel pump if there's an accident that stalls the engine . . . . On the other hand, if the engine simply stalls it might take longer to restart; it may also make the initial cold start harder on the battery (first you have to get oil pressure, then the pump comes on, etc., etc.) But from the pictures you've shown . . . . ????? (IMG:style_emoticons/default/dry.gif) Stay warm up there! |
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