1976 2.0L D-jet, distributor vacuum Options

[Ron914]

@emerygt350
I was asked my a member helping me with my high idle /vacuum leak problem how I currently have it hooked up .This is the diagram I am using .

[emerygt350]

Let me see if I understand what you posted. When you plugged the MPS vacuum at the plenum and gave the MPS 22inhg with a warm engine the idle dropped to where it is supposed to be, and the MPS is leaking down as well?

I would double check your valves because it is relatively easy, but check your vacuum at the plenum first, it would be nice to know where it is at currently. Use the MPS port on the plenum. Just hook your mityvac to it and read the vacuum off of that. Be sure the engine is warmish when you do check or at least that the aar is closed or blocked and the leaking MPS is unplugged. If the vacuum is up around 18-20 inhg I might not bother with the valves just yet.

I would also time your engine for the moment using the vacuum method. This is the way people used to time their engines in the old days. Disconnect the retard. Get the engine warm and idling at that 900 again (disconnect the mps or whatever was necessary). Check the vacuum, turn the distributor either way and watch the vacuum. You want to find the highest vacuum with the engine still running well. Then back it down 1-2inhg. If the vacuum is quite high (over 21inhg) I would just bring it down to 19inhg. If 19 or 20 is as high as it goes, I would maybe bring it back 1 inhg so it's between 18 and 19 just to be safe.

If you don't have much faith in your timing marks or the light this should work fine. You could now check the timing with the light and see where you are at idle and all in at 3.5k rpm.

Since you have a 2056 I don't know what to think about the 'euro spec' MPS. Sounds like the daiphragm is busted anyway so you will probably need one of Chris Foley's rebuild kits and at that point you will be tuning your own MPS anyway. I am not sure if the 2056 sucks enough gas over the stock to require that inline resistor though. Your ECU is already richer than the 73 that required that resistor. Better rich than lean and if you have a hunting idle, I would keep it for the time being. You might try richening the ECU pot to see if that hunting idle goes away.

While you are working on this you may just want to keep that retard disconnected until everything is where it should be, then deal with the retard afterward. The nice thing about the retard is that you can put some extra timing into your engine and still have it start up nice and easy but we are not there yet.