Official Fuel injection questions thread

[MuzzcoVW]

[plextor]

I just finished replacing all of the fuel lines, tank, etc. on my 1975 SB, and now I’m doing the vacuum lines. It seems as if the state of these lines was non-factory when I got the car, and I’m hoping y’all can help me with a few questions. I’ve got the Bentley manual but it doesn’t seem to have this level of detail (a line diagram would be perfect).

The original state of the engine as when I got the car:

This leaves me with a few questions:
1. The small vacuum line T-connector on driver’s side of engine doesn’t seem to match a OEM photo I found.
2. The EGR valve doesn’t seem to have any vacuum line connected, perhaps related to #1?
3. There seems to be the wrong kind of hose going from the T connector underneath the intake boot to just below the alternator pulley; which hose is this supposed to be?
4. It looks like there is a missing hose from the side of the air cleaner body’s oil gas mechanism back to the air intake; what’s the proper name of this hose?
5. The fuel line in this photo is going up over the coil and over to the cold start valve, but I think the proper routing is supposed to be below it; is that right?

Another view of the driver’s side vacuum lines for more detail (taken today).

[busdaddy]

I can't find the 75/76 diagram right now, here's the later one: https://www.thesamba.com/vw/forum/viewtopic.php?t=282555&highlight=vacuum+diagram , the EGR should have a line on it as well, Teed into constant vacuum somewhere. Make sure the EGR holds vacuum before connecting it.
That hose to the AAR is NLA, Kevin (KKiley) found one that fits from a Dodge or something, there's pics and a link somewhere back earlier in this thread.
That breather hose is NLA right now as well, is that port on the air cleaner actually open?, some aren't and they hook up similarly to what you have going on now.
Yes, that fuel line should be below the coil.

Edit: Here's some discussion on the breather as well as a vacuum diagram: https://www.thesamba.com/vw/forum/viewtopic.php?p=9313072#9313072
And here's a pic of the 75 system with arrows and colored lines and stuff:

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[plextor]

Adding this promotional photo of a 1975's engine bay for reference. Found at https://hips.hearstapps.com/hmg-prod/amv-prod-cad-...Beetle.jpg

[plextor]

[Lost69Convertible]

Plextor - I repaired my ‘79 FI system and brought it back to stock last year. I agree the EGR is low priority as long as the associated seals are good, no leaks.

The PO plugged the tube from the exhaust to the EGR diaphragm. I decided to leave it that way.
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[Maltboy!]

[plextor]

Thought experiment / advice needed.

Today was a start attempt. At this stage, I have replaced the fuel pump, fuel pressure regulator, all the soft lines fuel lines, cleaned the injectors, cleaned out the hard fuel lines (carb cleaner and air pressure), and replaced a variety of vacuum and breather lines to get it ready to go.

Before I hooked the fuel pump's power up to the car, I power cycled it with a bench power supply. It sucked some fuel into the system pretty quickly but after a few seconds it sounded like the system was pressurized, flow stopped, and the fuel pump started to pull more amps.

I didn't expect that to be normal, but I'm honestly not sure how the fuel pressure regulator does its job without engine vacuum (that is, should I expect fuel to freely flow throughout the whole system and back into the tank if the fuel pump only is running?) so I went ahead and hooked everything up for a full start.

As I expected, no dice. Oil pressure, etc. is good but fuel isn't making it where it needs to go.

Frustrated for a bit since I probably screwed up something along the way during this long process.

Thinking what might be wrong, I'm wondering now if I swapped the connections to the two hard lines from the fuel pump (so that I'm pumping into the back of the fuel pressure regulator, rather than the correct side and returning via the regulator). I'm pretty sure I triple checked this when I was cleaning out the hard lines, but you know how that goes.

At this stage, with the car assembled and fuel in the lines, etc. - what's my best course of action to find out why fuel isn't pumping in a loop through the system?

[plextor]

[busdaddy]

You are on the right track, the FPR allows flow regardless of vacuum, it reduces pressure when vacuum rises. Aside from a possible blocked line the swaped hoses is a good place to start, I don't think it'll pass fuel in reverse.

When you reinstalled the tank are you sure you didn't kink a line underneath?, it's easy to do, have a helper pull on them from below as you lower it into place.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[Lost69Convertible]

[plextor]

Good tips... stay tuned (probably next weekend!)

[busdaddy]

[walarson]

Greetings. I'm a rooking rebuilding a 1976 FI sedan. The question of the day is how the auxiliary air valve bracket is attached to the engine.

Does it attach to the engine stud noted in the pic? If so, I clearly have the wrong length stud for that purpose. Thanks in advance.

[busdaddy]

Since that engine has a blocked off fuel pump pad I'm guessing it's not the original case?. You are correct, the stud is where that goes, you'll have to double nut the stud to remove it, then install a longer one.

What's the diameter of that fancy looking pulley?, it may cause some cooling issues if it's smaller than 7.25". It's great for setting up and initial timing, but consider a stock sized one for daily driving once it's dialed in.
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[walarson]

[walarson]

Greetings. Please note the two types of fuel injector collar fittings for a 76 beetle sedan. I had the injectors cleaned and inspected and am now in process of installing them.

Issue: the hose on the injectors was too short (the guy who did the cleaning added the short hose sections) to get enough bend to put the assembly in place. I simply pulled hose off the barb of the left injector and added correct length of hose. My problem is how to get the short piece of hose off the injector on the right? Note it does not have a barb but a metal collar. Do I cut the hose? Dremel off the collar? I cannot pull or twist it off. I could always splice in a short piece of hose but that seems mickey mouse.

Any ideas are appreciated. Merry Christmas.

[busdaddy]

Those pushlok collars are OG equipment, so that makes the hose on that one 44 years old, you'll have to change it.
To remove you have two options, grind or dremel the collar, careful not to nick the injector or melt the plastic if it gets hot grinding. The other way is with a pointy Xacto knife, split the hose, you need the pointy knife to reach in under the collar, the caution with this way is don't slice up the plastic hose barb inside too much, lengthwise cuts make for tough sealing.

Use clamps to install the new hoses, that one on the left looks too long, I'd be concerned it'll kink.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[walarson]

[Bugeye54487]

Are both feed and return lines suppose to flow both ways. Seem one of mine is blocked and does not flow. No one way valve on the tank or anything? Any way to unplug it? 78 super FI convertable.