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GotBugged
Samba Member
Joined: September 26, 2021
Posts: 9
Location: Newburyport, MA
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 Posted: Sun Sep 26, 2021 12:41 pm Post subject: 1978 Super Beetle: Fuel Injection versus Carb |
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My wife and I recently purchased a 1978 Super Beetle Convertible, our first VW Bug, so we are just getting into this.
We are studying “The Compleat Idiot”, websites, The Samba, etc…. and trying to get up to speed.
A couple of notes before I ask my questions. The Beetle came with a Fuel Injected engine, but we decided to have it changed out to a 34 PICT 3 carb.
Question:
Because we changed from Fuel Injection to Carb, do we need to change the fuel pump type, etc...are there different pressure requirements, etc... and does this affect engine performance, or are all of the adjustments made on the carb adjustment screws?
Any thoughts, comments, and help would be greatly appreciated.
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1978 Super Beetle Convertible - September 2021 - Current |
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Michael Ambrozik
Samba Member
Joined: October 17, 2020
Posts: 631
Location: San Jose, CA
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| Posted: Sun Sep 26, 2021 2:49 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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| You have to many open posts. The anwdser is the fuel pump need to be a 2-3 psi pump if not the carb is going to flood. |
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Glenn 
Mr. 010
Joined: December 25, 2001
Posts: 76935
Location: Sneaking up behind you
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| Posted: Sun Sep 26, 2021 2:51 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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| Michael Ambrozik wrote: |
| You have to many open posts. |
Agreed. 6 posts and each was to start a new topic.
It's best to start a single topic and post questions there. That way you have a record and the history of your cars journey.
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
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Rome
Samba Member
Joined: June 02, 2004
Posts: 9651
Location: Pearl River, NY
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| Posted: Sun Sep 26, 2021 6:37 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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| Quote: |
| The anwdser is the fuel pump need to be a 2-3 psi pump if not the carb is going to flood. |
I agree. In the photo of your engine from your "heat riser" post, your engine is still based on a fuel-injected case which did not have the opening nor the 2 studs for a mechanical pump from a carbureted engine. Those would be located to the right of the distributor on the left half of the case. This leaves the only option being a low-pressure electric pump that turns on as long as the ignition is on. Important to mount the pump up near the fuel tank, not back by the engine, because most of the pumps tend to be designed to push the fuel back to the engine. Most pumps use a "pulsing" internal movement which transmits to the pump housing. To mount the low-pressure pump, you'll need to mount it onto rubber buffers so that the pulsing does not transmit to the body. You can carefully remove your high-pressure original pump which put out about 28 psi by comparison. On my '77 Standard Beetle which was also originally FI, the PO removed the factory pump and installed a low-pressure pump onto the same rubber-isolated mounting studs on the passenger side vertical wall of the bulkhead. The pump has only 2 wires, + (for ignition on) and - which is a ground and can be connected to any good metal ground nearby.
Your fuel tank will have a return line from the original FI system which will need to be plugged, since the carburetor has no provision for routing excess fuel back to the tank. |
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Xevin
Samba Member
Joined: January 08, 2014
Posts: 7628
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| Posted: Sun Sep 26, 2021 9:38 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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| Glenn wrote: |
| Michael Ambrozik wrote: |
| You have to many open posts. |
Agreed. 6 posts and each was to start a new topic.
It's best to start a single topic and post questions there. That way you have a record and the history of your cars journey. |
Yes. It’s mind boggling 
Sometimes it does help to start a new thread on something specific to be read. Your threads are rapid fire and now kinda all over the place. I wonder if a moderator could clean all that up in to one thread 
And if a moderator does. Consider kicking in some coin to The Samba. Do it anyway 
https://www.thesamba.com/vw/premium_membership.php
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Keep on Busin'
| 67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
| Clatter wrote: |
| Damn that Xevin... |
| skills@eurocarsplus wrote: |
I respect Xevin and he's a turd  |
| SGKent wrote: |
| My God! Xevin and I 100% agree |
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KKiley
Samba Member
Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Mon Sep 27, 2021 12:41 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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Removing that Fuel Injection was just the work of amateurs, instead of fixing any issues. If they didn't know the difference between a FI pump and a carb version, they should not have tried the conversion.
Good luck sorting it all out.
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1978 Super Beetle convertible
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Lingwendil
Samba Member
Joined: February 25, 2009
Posts: 3988
Location: Antioch, California, a block from the hood
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| Posted: Mon Sep 27, 2021 1:31 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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| GotBugged wrote: |
Because we changed from Fuel Injection to Carb, do we need to change the fuel pump type, etc...are there different pressure requirements, etc... and does this affect engine performance, or are all of the adjustments made on the carb adjustment screws?
Any thoughts, comments, and help would be greatly appreciated. |
Going to a carb from factory fuel injection will perform worse than running properly functioning fuel injection. Not much worse, but it is for sure a noticeable difference. The fuel injection on these cars works pretty darn well, and is as easy to maintain or troubleshoot as a carb in my opinion and experience.
Only way I would consider going to carb from factory EFI is if all the EFI stuff is completely shot, or missing. The 34-3 carb is an inferior system.
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whobba
Samba Member
Joined: March 19, 2002
Posts: 871
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| Posted: Mon Sep 27, 2021 2:49 pm Post subject: Re: 1978 Super Beetle: Fuel Injection versus Carb |
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I've had a few of the late model FI beetles, and the FI systems work great when a person understands how they work. I feel that the mechanic who worked on this VW didn't want to take the time to figure out the L-Jet system, so this poor owner gets stuck with a big bill and a crappy set up. Also, purists would balk at buying a VW that's been converted from FI to a carb, since it's not era appropriate. Now the guy has to figure out the new problems for the inferior carburetor set up. I feel for him.
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