After a year of everything going great, over the last month my '93 Eunos with Reverant's MS2 Basic has started having a high idle (around 1400 rpm), even when warmed up. Logs show that the PWM Idle Duty is stuck at 41.2 when it should be around 32 when warmed up.
Any idea how I can diagnose what has gone wrong? I've tried old maps, closed loop idle control, open loop idle control, etc. The idle valve tester in TunerStudio shows that the idle valve is working ok, it's just that the Megasquirt keeps asking for a value of 41.2 :(
This brings up something I was going to make a thread about.
Has anyone noticed issues with high mileage (150k+) TPS sensors? I soldered in an NB pigtail to Oregonmon's '90 wiring harness, which is PNP into one of Rev's MS3s, so I doubt it's wiring/MS3 related.
But we've not tested 3 sensors that go 5-20% negative when you just barely touch the throttle.
Owner of a local shop that specializes in Miatas says he's only replaced about 3 TPS sensors in the last 7 years. Our only thought is that the stock ECU doesn't really care how precise the TPS is. But when 2% keeps it at 1400rpm and 1% is back in CL idle, it's damn important.
This video is of me slowly moving the throttle wheel by hand, I turned it smoothly and only clockwise.
Although the TPS varies by less than 0.5% when idling, I noticed that it seems to 'drift'. For example, TunerStudio was showing closed throttle at around 0% after re-calibrating, but nearly 2% once I had got back after a drive! After a few minutes it settled down to about 1%.