Yesterday, I decided to do some tuning after finalizing the intake manifold setup. Tuned it from 2,000 rpm down to idle. Mostly was running rich, especially 1500 and down. Got it running very good, a little on the lean side except at high manifold pressures. Idle was about 800 rpm and Lambda varied from high .9's to 2- something. Throttle tip in was very good, better than it had been in a long time.
This afternoon, I started it up to move it to the basement entrance to trial fit the Parish top I am modifying. Idle was very slow and poor. It would not take fuel. Made a data log, it was running at about 400 rpm (and lower) and Lambda's were .77-.80. I've never see them that rich. So, 3 hours later, after much data logging and adjustments, it was running at 800 rpm. After turning the idle screw in about a half turn (it is now idling at 1% throttle) and leaning out the entire bottom end about 5%. Throttle tip in is okay, but not as good as yesterday. Took it out for a trial run, it seems the 2000 rpm tune is still okay.
Its not like this is anything new. The rule of thumb is, the better it is running after a tuning session, the worse the will run the next day. I was hoping the manifold would cure that.
The bad part is this is exactly what was happening when I was tuning the Weber on the Pinto 2.0. Run fine today, like crap tomorrow. I thought the switch to EFI would put that behind me.
Bill
This afternoon, I started it up to move it to the basement entrance to trial fit the Parish top I am modifying. Idle was very slow and poor. It would not take fuel. Made a data log, it was running at about 400 rpm (and lower) and Lambda's were .77-.80. I've never see them that rich. So, 3 hours later, after much data logging and adjustments, it was running at 800 rpm. After turning the idle screw in about a half turn (it is now idling at 1% throttle) and leaning out the entire bottom end about 5%. Throttle tip in is okay, but not as good as yesterday. Took it out for a trial run, it seems the 2000 rpm tune is still okay.
Its not like this is anything new. The rule of thumb is, the better it is running after a tuning session, the worse the will run the next day. I was hoping the manifold would cure that.
The bad part is this is exactly what was happening when I was tuning the Weber on the Pinto 2.0. Run fine today, like crap tomorrow. I thought the switch to EFI would put that behind me.
Bill