 Fuel Pressure?, Pump and Regulator |
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| stoneman30hotmail |
 Aug 29 2023, 06:03 PM
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#1
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Member  Group: Members Posts: 80 Joined: 10-September 22 From: Greensboro, NC Member No.: 26,834 Region Association: South East States  |
I have a 1.7L. The pump I have looks like this.
 https://www.lceperformance.com/ProductDetai...eUaAvWtEALw_wcBWhere I see it says it is 5psi and recommends a pressure regulator. But I don't see one. I have this single carb.  How bad is that? Do I really need a regulator? What is going on without it? Related is that the PO said they recently gave up on FI. But I assume no engine work was done. I found this pump in the trunk.  Recommendations? |
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| ndfrigi |
Aug 29 2023, 08:47 PM
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#2
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Advanced Member Group: Members Posts: 2,928 Joined: 21-August 11 From: Orange County Member No.: 13,474 Region Association: Southern California 
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1. The lower fuel pump you saw was the original FI fuel pump with around 30 psi.
2. Looks like previous owner replaced the fuel pump to low psi. If it indicated 5psi. You need pressure regulator that can lower it to 2 psi. 3. Single carb usually need only between 2 to 3 psi. |
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| brant |
Aug 30 2023, 10:56 AM
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#3
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914 Wizard Group: Members Posts: 11,623 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains 
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your question about whether you need the regulator:
the needle and seat in the carb stops the fuel from flowing in. they can stop and handle pressure around 3psi... sometime 4psi but much higher and they will blow the needle open and continue to add fuel to the carb even if the bowl is full already. So the bowl can overflow and start a fire if the leaking gasoline hits the headers or another source of ignition. |
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| rjames |
Aug 30 2023, 12:55 PM
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#4
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I'm made of metal Group: Members Posts: 3,932 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest
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Did the PO give you the FI stuff, too? If so, consider putting it back on the car. Single carb is the least optimal config.
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| VaccaRabite |
Aug 30 2023, 02:07 PM
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#5
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En Garde! Group: Admin Posts: 13,443 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Its probably an internally regulated pump thats pushing 5psi fuel.
Note I said PROBABLY. You really do want to put a regulator in line. There are many around that are 1-5psi for carb use. Get one and use it. Zach |
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| stoneman30hotmail |
Aug 30 2023, 03:07 PM
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#6
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Member Group: Members Posts: 80 Joined: 10-September 22 From: Greensboro, NC Member No.: 26,834 Region Association: South East States |
QUOTE(rjames @ Aug 30 2023, 02:55 PM)  Did the PO give you the FI stuff, too? If so, consider putting it back on the car. Single carb is the least optimal config. Looks like they sold the good stuff. |
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| stoneman30hotmail |
Aug 30 2023, 03:13 PM
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#7
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Member Group: Members Posts: 80 Joined: 10-September 22 From: Greensboro, NC Member No.: 26,834 Region Association: South East States |
QUOTE(brant @ Aug 30 2023, 12:56 PM) your question about whether you need the regulator: the needle and seat in the carb stops the fuel from flowing in. they can stop and handle pressure around 3psi... sometime 4psi but much higher and they will blow the needle open and continue to add fuel to the carb even if the bowl is full already. So the bowl can overflow and start a fire if the leaking gasoline hits the headers or another source of ignition. Good to know. We did smell gas pretty stong after the 3 mile drive home a year ago. It's probably this and/or the open carbon canister lines. Not sure how much the PO drove it since the changeover. |
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| porschetub |
Aug 31 2023, 02:26 PM
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#8
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Advanced Member Group: Members Posts: 4,698 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
QUOTE(stoneman30hotmail @ Aug 31 2023, 09:13 AM) QUOTE(brant @ Aug 30 2023, 12:56 PM) your question about whether you need the regulator: the needle and seat in the carb stops the fuel from flowing in. they can stop and handle pressure around 3psi... sometime 4psi but much higher and they will blow the needle open and continue to add fuel to the carb even if the bowl is full already. So the bowl can overflow and start a fire if the leaking gasoline hits the headers or another source of ignition. Good to know. We did smell gas pretty stong after the 3 mile drive home a year ago. It's probably this and/or the open carbon canister lines. Not sure how much the PO drove it since the changeover. Wonder why they sell a pump making 5psi for Webers when I've never known of a Weber needing that pressure but I could be wrong ? ,maybe the pump isn't making that pressure as the fuel would be overflowing as mentioned . Holley low pressure regulator has been a good unit in my application but you will need a gauge to set the correct psi . |
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