Printable Version of Topic
Click here to view this topic in its original format
914World.com _ 914World Garage _ Fuel Pressure?
Posted by: stoneman30hotmail Aug 29 2023, 06:03 PM
I have a 1.7L. The pump I have looks like this. 
https://www.lceperformance.com/ProductDetails.asp?ProductCode=1035046& amp;gclid=Cj0KCQjwi7GnBhDXARIsAFLvH4lGGW4PFDPEuNsmAsYnKh5UVYNnja3Chwzd4lEz2Zm4Ia
HpCBzu1eUaAvWtEALw_wcB
Where 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?
Posted by: ndfrigi Aug 29 2023, 08:47 PM
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.
Posted by: brant Aug 30 2023, 10:56 AM
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.
Posted by: rjames Aug 30 2023, 12:55 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.
Posted by: VaccaRabite Aug 30 2023, 02:07 PM
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
Posted by: stoneman30hotmail Aug 30 2023, 03:07 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.
Posted by: stoneman30hotmail Aug 30 2023, 03:13 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.
Posted by: porschetub Aug 31 2023, 02:26 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 .
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)