1976 fuel injection questions Options

[Ron914]

Hello ,
I covered the inside idle screw air intake port inside the TB as you advised and my idle is now down to apx 950 . I am taking the cat in Monday to have a smog test down I will post the results afterwards and hopefully more photos . This is my first attempt trying to add a photo.
Thank you for your help
Ron
@Burton73 , @emerygt350

[emerygt350]

Great news. What a nice looking car! Just out of curiosity... how did you end up covering it?

[fiacra]

Good luck on Monday. Fingers crossed. If it doesn't pass post the results so we can see where it fell out of range. The numbers will help dictate what you need to do to get it within passing range. Hope not to hear any bad news!

[Ron914]

Great news. What a nice looking car! Just out of curiosity... how did you end up covering it?

On the inside of the TB with a small piece of aluminun foil air duct tape , its flatter and very sticky but there is no adjustment of the idle screw so I need to figure out where my vacuum leak is coming from . I am going to purchase a smoke machine and see if I can find any leaks but I am thinking the TB may be bad.

[JeffBowlsby]

You might also try a smoke pen/pencil. Lower investment cost for the same result.

[emerygt350]

Is your vacuum retard can on the distributor hooked up correctly?

[Ron914]

Is your vacuum retard can on the distributor hooked up correctly?

Because my car motor was disassembled when I purchased it so I have to assume the parts are original but I really don't know for sure . I have two lines coming off my distributor .I hooked it up per the diagram I found in tech notes from Jeff posted below one side goes to the bottom of the TB (vacuum) the other to the air cleaner. /Users/ron/Desktop/914 World Photos/Screenshot 2025-01-11 at 8.04.01 PM.png
Looks the diagram didn't upload , thought I had the photo posting down .I'll try again.

[Ron914]

Lets try the photo again

[JeffBowlsby]

Hose 10 is not connected to anything on a 1974-76 2.0L car. Its just an open hose terminating under the air plenum as from the factory.

[Ron914]

Hose 10 is not connected to anything on a 1974-76 2.0L car. Its just an open hose terminating under the air plenum as from the factory.

Thanks Jeff ,
I have hose 10 connected to the air cleaner so your saying just unconnected it from the air cleaner and let it lie under the plenum .

[Ron914]

I don't think that this is the source of my vacuum leak

[Ron914]

should the #10 hose be plugged or left open to air ?

[Ron914]

should the #10 hose be plugged or left open to air ?

This is a photo of my butterfly plate with the hole plugged with a screw/nut.

[Ron914]

When I first assembled my motor I followed this diagram .Since I did not disassemble the motor and was a newby I thought this diagram was correct for all cars 74-76 and I bought a anti-flashback valve from Bruce .I later found out from someone that a 76 did not use the anti-flashback ,however my valve covers have 13mm hose connections on them . I was not sure the what the valve covers should be connected to so the valve covers are open to air now . In this diagram they show connection between the anti-flashback and the valve covers . Do I need to remove those covers and purchase ones without holes ?

[Ron914]

When I first assembled my motor I followed this diagram .Since I did not disassemble the motor and was a newby I thought this diagram was correct for all cars 74-76 and I bought a anti-flashback valve from Bruce .I later found out from someone that a 76 did not use the anti-flashback ,however my valve covers have 13mm hose connections on them . I was not sure the what the valve covers should be connected to so the valve covers are open to air now . In this diagram they show connection between the anti-flashback and the valve covers . Do I need to remove those covers and purchase ones without holes ?

I did buy a set of aftermarket valve covers from a members garage sale but they did not come with mounting hardware .I am still trying to locate the proper hardware but maybe I would be better off located the proper stock covers . Forgive all my post post photos as I am practicing adding photos so I can get this memorized .

[rjames]

should the #10 hose be plugged or left open to air ?

This is a photo of my butterfly plate with the hole plugged with a screw/nut.

As I stated previously, that nut in the butterfly was someone’s attempt to bring the idle down because of a vacuum leak.

The number 10 hose should not be connected to the air cleaner. Fully remove it from the car (leaving the port on the diist open to the air) or just leave it disconnected from the air cleaner as Jeff described. Do not plug it.
Look at Jeff’s diagram. What port on the air cleaner was the hose connected to on your car? Determine what should be connected there. (I’m guessing the decel valve as people often connect it incorrectly or remove it altogether.)

I’d go back to the stock valve covers with cork gaskets. Try installing with the VW logo upside down to avoid leaks.

[emerygt350]

We should walk you through all the vacuum hoses. All ports on the plenum/aircleaner/etc have important things to do and the maps can be confusing (and some of them are wrong).

I believe the one you posted is good, but you misunderstood it (because the fact porsche just left that hose laying open on top of the engine is unanticipated by any sane person). There are also oddities (for example passive PCV) that starts up in 74/75 somewhere and could really throw you off.

But the fact you had it hooked to something else means something else was not hooked up correctly.

I would check your hoses in this order.
decel valve
mps
distributor
aar
pcv system
evap system

They need to go to exactly the ports shown on the diagram. Each of those ports can be a different size.

Check to see if you actually have a pcv valve and see if it is working. The valve disappears when they go passive and the old line that went to the plenum then just goes to the air cleaner instead. A picture of your air cleaner box and that area of the plenum where the pcv enters in the diagram will tell us lots about how things are going.

[emerygt350]

We should walk you through all the vacuum hoses. All ports on the plenum/aircleaner/etc have important things to do and the maps can be confusing (and some of them are wrong).

I believe the one you posted is good, but you misunderstood it (because the fact porsche just left that hose laying open on top of the engine is unanticipated by any sane person). There are also oddities (for example passive PCV) that starts up in 74/75 somewhere and could really throw you off.

But the fact you had it hooked to something else means something else was not hooked up correctly.

I would check your hoses in this order.
decel valve
mps
distributor
aar
pcv system
evap system

They need to go to exactly the ports shown on the diagram. Each of those ports can be a different size.

Check to see if you actually have a pcv valve and see if it is working. The valve disappears when they go passive and the old line that went to the plenum then just goes to the air cleaner instead. A picture of your air cleaner box and that area of the plenum where the pcv enters in the diagram will tell us lots about how things are going.

I would also add that a vacuum leak isn't the end all with d-jet. It won't affect your air fuel ratio or the computer or anything like that, it will just make the idle go up. The fact the hole in the butterfly is filled doesn't mean the car isn't running correctly, it's just the engine is getting that little bit of extra air from somewhere else.

[rjames]

Check to see if you actually have a pcv valve and see if it is working.

‘75/76 2.0 cars did not have the PCV valve.

[Ron914]

We should walk you through all the vacuum hoses. All ports on the plenum/aircleaner/etc have important things to do and the maps can be confusing (and some of them are wrong).

I believe the one you posted is good, but you misunderstood it (because the fact porsche just left that hose laying open on top of the engine is unanticipated by any sane person). There are also oddities (for example passive PCV) that starts up in 74/75 somewhere and could really throw you off.

But the fact you had it hooked to something else means something else was not hooked up correctly.

I would check your hoses in this order.
decel valve
mps
distributor
aar
pcv system
evap system

They need to go to exactly the ports shown on the diagram. Each of those ports can be a different size.

Check to see if you actually have a pcv valve and see if it is working. The valve disappears when they go passive and the old line that went to the plenum then just goes to the air cleaner instead. A picture of your air cleaner box and that area of the plenum where the pcv enters in the diagram will tell us lots about how things are going.

I would also add that a vacuum leak isn't the end all with d-jet. It won't affect your air fuel ratio or the computer or anything like that, it will just make the idle go up. The fact the hole in the butterfly is filled doesn't mean the car isn't running correctly, it's just the engine is getting that little bit of extra air from somewhere else.

I know I don't have a PCV evap/system on the car from what I can figure out at this time. I have the decel disconnected ,the AAR is working as it should. and closes after a warm up. The other hose from the distributor is connected to the air cleaner so I will remove and just let it lie below the plenum and leave open.The distributor vacuum is hooked to the bottom of the TB (vacuum).I believe I have the MPS hooked correctly . I will pull the car out in a bit and attempt to post photos again and identify the hoses.I purchased a stacked vacuum elbow from AA but do not have it installed as I disconnected the decal to see if it was my problem . I just put the engine lid back on so it's hard to get good photos so I will have to remove it .Its definitely a hard car to work on because of the access .Give me some time and I will get back to you with some photos