A couple of questions on LM1

[KevinG]

I bought a used LM1 with RPM adaptor, and I have a couple of questions:

1) I programmed my RPM adaptor using my PC for the 3 sparks per crankcase rotation option, and connected it to the trigger wire from my Crane optical ignition module. I am not getting any data logged on my LM1 though. Any ideas where I could have gone wrong?

2) I have been trying to set basic fuel/air running the motor in the garage prior to taking it on the road, but the results from several runs are not what I expected. Generally, the LM1 shows lean at idle progressing to rich at higher rpms. This is just the opposite to what I expected to be the case. More specific details follow the description of my motor, which is a bit unusual.

The motor - Car is a '72 T with a stock 2.4 bottom end and a 2.2S top end. It has 2.2S pistons, cylinders, heads, cams and a 2.2S MFI system in good working order. Exhaust is a 2-in 2-out sport muffler on stock heat exchangers.

Average readings from the LM1 are:
Idle - 900rpm 15.25 AFR
2,000rpm 16.50 AFR
3,000rpm 13.00 AFR
4,000rpm 11.50 AFR
5,000rpm 10.90 AFR
6,000rpm 11.90 AFR

The increase in lean from idle to 2K rpm and the increase in rich at 5K rpm (and back at 6K rpm is consistent over several runs.

Initially, all readings were very rich - at the 10.1 to 10.4 range, and I made progressive leaning adjustments of the main rack to arrive at the above. Further leaning leads to dangerously high lean conditions at 2K (21-25 AFR).

After the initial leaning adjustments, idle RPM progressed to about 2k, so I checked the linkages from the throttle shaft to the throttle bodies and found that they were keeping the butterflys off the stops when the pump linkage was set at the correct length. I reset the throttle linkages (lengthened) to allow the butterflies to just contact the stops at idle, and idle rpm returned to normal. Throttle linkages are now at 149mm center to center. I have not been able to check what allowable lengths are as of yet, but airflow remains synchronized for all cylinders at this setting.

If I lengthen the throttle linkages, I suppose that this would accelerate throttle opening and possibly improve the rich condition at higher rpms. Conversely, this would result in the higher idle speeds that could not be corrected by the idle air screws. So...

I would appreciate any suggestions on how to approach the problem.

Thanks,

Kevin