choppy RPM?

[Olds442FI]

So now that i know VEMS can compensate for oversize injectors quite nicely I am having one other small issue. As i run through the RPM ranges it doesnt always seem so smooth. I would expect it to be a little jumpy at idle with the cam and all but i am getting this heart beat looking line on the VE Logger as i try to hold an rpm. It almost seems that it is pulsing to something like a heartbeat. The pulsing seems to be visually clearer in the VE Logger @ about 3000 RPM and up. It shows very slight jumps in the timing and the duty cycle and really slight in the pw and Most noticable in the rpm. These jumps seem to be  timed together exactly and This is making it diffacult to zero in on my lamda because thai jumps .1 as well.  I have checked all of my ignition wires and everything seems ok. Ill have to look at night to see if i can find any ignition leaks.It probably is arcing somewhere because the jumps seem to be about 3 per second @ 3000 RPM. So now that im searching ignition stuff this leads me to a few questions as always .

1. should i be using a falling or rising trigger? originally i was set to rising and later set it to falling. it runs on both with a little twist of the distributor. I know from a previous post that the falling trigger should be for a hall sensor. well this is a hall effect distributor so is there a difference between hall and hall effect? here is a link to the distributor that i have. http://www.summitracing.com/parts/MAA-6148201/.

2.TDC after trigger - In my primary trigger settings this is set to 70 degrees. not quite sure what this is for either.

[rob@vems.co.uk]

A jump in RPM would suggest the trigger as being an issue, you shouldnt be caring about trying to tune fuel if you have a trigger problem. 
Hall and Hall effect are one and the same thing, leading edge means that the ecu triggers as the hall signal rises, trailing as it falls, its simply a case of trying one then the other, and adjusting your TDC after trigger value to set the base timing correctly.
TDC after trigger is there to enable you to calibrate the base timing, you set the cranking advance to 10, disconnect the fuel supply, crank the engine and use your timing light to check that the ignition is firing at 10deg BTDC, you then either adjust the distributor to get the timing correct - or you adjust the TDC after trigger value, you want the TDC to be around 100->60 so you might be best to move the distributor to tune it, then use TDC after to fine tune it.

[mattias]

I would make sure that the rotor is pointing straight at the ignition lead when the cylinder is at 30 degrees before TDC, as that is where you'll spend most of the time with the engine running.
 Calibrate your "TDC after the trigger" after having that fixed, naturally this number syncs the trigger pulse and TDC of the engine.

[Olds442FI]

so until i get a chance to try to change to a rising trigger and see if that helps does anybody have have a good looking data log that i can see just to get an idea of how the lines should look? sometimes just seeing how things a should look can be a huge help, and it would give me a little bit more a focus on the goal. Its kinda like a pineapple, if someone described it but you never seen one, you would simply never get an accurate picture of what it looks like

[Olds442FI]

Problem solved! I re-adjusted from a falling trigger to a rising trigger. This cleared up my logging so that the resolution on the VE logger is sooo much better. Now my RMP reads nice smooth lines and the car runs with lots more power. It seems that all the adjustments i have made so far with the VE table still work out fine, and now i think that i am close to getting a super good fuel table worked out. I guess this means this thread is closed and onto opening a new one in fuel .. Special thanks to Rob and Mattias!