I have been tryng to find the right combination with my new motor. At times it seems I have it pretty close but there is always some hesitation accelerating through around 2,000 RPM. I can get some serious bucking at times.

Now the Capn tells me my webcam isn't going to make me happy and I am willing to believe that this may have no real solution, but I am puzzled because I had it pretty close, and then during an autocross it got worse.

I am wondering what wants to give up during acceleration. I am specifically worried about:

My pertronix ignition. There have been failures. Are they on then dead failures or is there an intermittent phase?

Coil? Any reason that would care? How about funky coil and obviously weird Optima battery? Reading about 12.5 V (not 13.5) during the events generally.

Fuel pressure stays constant like a rock when I can see the gauge in the engine well.

Wiring is, well old. Maybe I need Jeff's help?

OK, chime in. Please?

what does your engine idle at?

3500 rpm is from general crusing

5500 rpm or so is redline

I don't know that you should expect too much at 2000

jim

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I aim for 950 idle

Can pull hard at 3000

But in cruising I cannot slowly ease up a notch very easily. It seems to require a lot of drama. Yeah the burst of fuel from WOT makes it go.

I have also tried both the rich and lean sides of the MPS curve and cannot quite get smooth. Right now I have even lost cannot quite. Also have tried various approaches to timing from stock to both sides.

Vacuum at idle is even 17 inches, Proper changes on acceleration.

Check the vacuum ignition advance.

Very possible. I was chasing intermittent problems on my 1.7L DJet for months and my engine harness looked OK from the outside.
At some point i decided to take it out and inspect it closer. I found multiple fractures and other problems, all hidden by the heavy insulation.
It took 3 donor harnesses and a full weekend to make one good one (should have just bought one from Jeff!).

After fixing the harness the difference in running was drastic, the engine ran sooooo much smoother, better idle, more power, no more intermittent problems.
There is a thread here somewhere that i posted back in the day.

Well worth the time and money ...

it sounds like timing... so the vacuum advance is a great suggestion

also, are you using a wideband o2 sensor to play with the MPS?
don't adjust an MPS without one.

brant

Wide band. Plus an inductance meter, and finally a cap drilling so I can insert tools to adjust both screws at once without disturbing the stop. I think you need it all in the end, and I am still flailing a bit.

I have a 76 so in theory I can only be retarded, but I retrofitted an older throttle body to try both. It added power to the original engine, but doesn't seem to do as much this time. Both advance and retard move the proper amount at the indicated vacuum values according to the manual.

But your vacuum profile changed with the new cam. More specific, longer duration cam means lower vacuum at low RPM.
Since you say retrofitted: where does the vacuum for the advance come from? Before or after the throttle? It should be before the throttle but later TB have only the retard port after the throttle.

Can you expand on the first part Valy? Like a suggested course of action?

The TB comes from an earlier car with the advance just above the plate so it sucks after take off. I think that is correct - tough I had it backwards for awhile - it helps to actually take the cap off and pull vacuum on each side to see what happens.

I haven't seen your thread in a while . 1st re: Petronix. I think they are good or bad, no in between but you can call them and ask. They're very eager to assist. They list the phone # on their website. I think Brant is on about the timing issue. When timing, does the timing mark make a smooth transition when bringing up the rpm or dance around? Which cam did you end up with? IIRC, you were going with Rabies 9550 or the Web 73. I had the 9550 2.0 and it transitioned very smoothly. Just wanted to idle a bit rich but I knew that trade off was there before hand. BTW I did not have the dizzy re-curved and ran Petronix, also. When I first got the 2.0 running it was "jerky" but that turned out to be the MPS. I had one for a 1.7 that was re-calibrated & tested by Geoff. And I sold that MPS with the engine. I didn't want the next owner to have to chase down that stuff.

First thing I would set the advance higher to see if that helps with the acceleration. This will compensate for the low vacuumatic advance. The drawback is that the max advance will be a bit too high so high rev won't be good. Again, this is just to confirm the problem.
If it helps, you'll need to solve it with a re-profiled di$tributor.
Since I know you're a DIY guy, you just need to figure out how to activate the vacuum actuator on the dizzy at lower vacuum. Maybe a different spring...