I thought I would open another thread since the MPS was definitely bad. I believe I may have another problem, but had to rectify the MPS first.

Update - June 15th:

The MPS on my car was blown. I replaced it this evening (thanks Ron) with one that tested to spec. The car's performance improved (no backfire!), but it did not cure the hunting at low idle. Adjusting the idle screw did not affect the idle speed.

Next, I hooked up a vacuum gauge to the throttle body (did not tee it - just blocked off the hose going to the diagphram (retard side) of the distributor. I measured 13.5 inches of vacuum - so that is a little low. Need 15 inches - correct?

However, the car now idled and I could adjust the idle screw, which adjusted the speed to 950 without a problem. It stayed rock steady at 950. Connect the vacuum hose from the dizzy to the throttle body - the car low idle hunts/dies again. Removed and blocked off - 950 rpm.

I take the Mighty Vac this morning - start the car and pull 15Hg of vacuum on the diaphram. The car idles at 950rpm, but I notice there is leakdown to about 5 Hg within 60 seconds. Even after leakdown the car idles. Reconnect the vacuum hose from the throttle body to the retard side of the dizzy - car hunts/dies.

So - is the problem the dizzy or just the Vacuum Diagphram? I will recheck the timing to see if I set static timing correctly at TDC or the 7.5 BTDC mark. Timing was dead on - 27 deg BTDC - but I will double check. and Dwell at 48.

Question 1: How to test the diaphram? Pull 15HG and see if it holds it for x minutes?

Question 2: Does this sound more like a timing issuem than a fuel issue?

Looks like I still may have a small vacuum leak somewhere else, unless I am measuring it wrong.

So progress. The MPS needed replacing, but the idle is still the same - although no longer burning rich.

Thanks in advance.

Frank

Set the timing at 27 degrees at 3500rpms hoses off the throttle body after junking the points for a electronic setup.
Drive the car until is really warm, 20 minutes and then adjust the idle speed with a Co meter or the knob on the ECU to the notch. Then set the air bleed screw to adjust the rpms to 950.
Make sure at this time the AAR valve is fully closed!!! If not you are chasing your tail. Lube the AAR valve with PB Blaster by squirting in some after removing a hose. A sticking AAR valve will drive you crazy by being open sometimes and closed other times fouling your idle speed.

I would guess that you have a leak. Check the hose first, they certainly get old and cracked. Then suspect the diapham.

Dave

Success!

I had a partially stuck open AAR valve.

Did not open far enough for idle when cold - stayed open when the engine was warm.

I sprayed PB Blaster in the valve and let it soak for about 15 minutes. After I started the car - I check the AAR hose and the suction was quite strong. So the valve opened fully.

I drove it for 20 minutes - it drove really well. The valve closed fully. I adjusted the throttle to 950 rpms.

The car now idles when cold or warm. No surging - no hunting.

I still want to confirm Fuel pressure and CO, but will have to wait until later this week.

Thanks to everyone for their help - I have learned a tremendous amount about D-Jetronic over the last few weeks - but realize I have plenty more to learn.

Frank

Do I win anything for being right?

Gawd, I am on a roll! I got Blairs car running today!