Adjusting Air / Fuel Mixture Options

[sjhenry1075]

Hey everyone, please excuse my lack of knowledge on this subject, but I have a question regarding air / fuel mixture adjustment on my 71 1.7 with stock D-jet. I posted this question on Facebook but wanted to try here as well.

Back story: my car will only idle and drive when both vacuum lines are disconnected from the distributor. When connected (I used a diagram found on 914world so I know they aren't flipped) the car barely idles when cold or warm, and it is almost undriveable; it surges, bucks, and hesitates. If I remove both vacuum lines from the distributor it idles and runs great.

From what I understand from the replies on FaceBook, this could be an air/fuel mixture issue, but how is that adjusted with for the 71? Is there a certain procedure for this?

Thanks in Advance for any assistance you can provide!

For those going to PA for the Northeast gathering, I'm looking forward to meeting you!

[rjames]

Agree that you should verify fuel pressure, timing and proper valve adjustment and your distributor first.

More info on you car would help. D it run ok at some point? If yes, did you make any changes to anythinl before the issues began?
Do you have the right MPS and ECU for your car? Has anyone tampered with the MPS already (evident by epoxy seal being gone or screws in place of the four rivers holding the two halves together)?

[sjhenry1075]

Agree that you should verify fuel pressure, timing and proper valve adjustment and your distributor first.

More info on you car would help. D it run ok at some point? If yes, did you make any changes to anythinl before the issues began?
Do you have the right MPS and ECU for your car? Has anyone tampered with the MPS already (evident by epoxy seal being gone or screws in place of the four rivers holding the two halves together)?

The car is 100% original. My father is the previous and original owner of the car. I got the car in 2014, and until last year (COVID project), it hadn't been started or driven in a decade or longer.

Since acquiring the car I've done basic maintenance: oil change and filter, SS fuel lines, new fuel hoses throughout, cleaned the fuel tank, had the fuel injectors serviced, adjusted the valves, set the timing and dwell. The ECU is original, as are pretty much all the other parts of the engine.

How do I check and set the fuel pressure?

[rjames]

Agree that you should verify fuel pressure, timing and proper valve adjustment and your distributor first.

More info on you car would help. D it run ok at some point? If yes, did you make any changes to anythinl before the issues began?
Do you have the right MPS and ECU for your car? Has anyone tampered with the MPS already (evident by epoxy seal being gone or screws in place of the four rivers holding the two halves together)?

The car is 100% original. My father is the previous and original owner of the car. I got the car in 2014, and until last year (COVID project), it hadn't been started or driven in a decade or longer.

Since acquiring the car I've done basic maintenance: oil change and filter, SS fuel lines, new fuel hoses throughout, cleaned the fuel tank, had the fuel injectors serviced, adjusted the valves, set the timing and dwell. The ECU is original, as are pretty much all the other parts of the engine.

How do I check and set the fuel pressure?

to check fuel pressure you'll need to buy or rent a fuel pressure tester for FI. Your FLAPS will likely have one you can rent. Adjustment is made at the fuel pressure regulator. in the engine compartment. Since your car is 100% stock and was always in your family, I doubt you'd need to adjust the fuel pressure. More likely that you'r filter is clogged, the filter screen in the tank is clogged, or your fuel pump isn't pumping enough fuel.

How old are the fuel lines? If they haven't been changed in several years, I'd probably start there and replace the fuel filter. That may just solve your issues.