1993 RX-7 R1... Not stock, carry bail money :-)
7-13-03 / 10 hours
/ 1202 total
Got in two engine runs today. The first one showed
that I had two persistent oil leaks. I now HATE Earl’s
fittings. The engine started fine, then got rougher as it got warm.
Turning off the primary now causes the engine to quit, just as if you turned
off all the fuel. In fact, you can see the AFR go from rich, to nothing
in just a second or so. Turning off the secondary doesn’t do
anything. Even with the mixture full lean, the AFR meter shows very
rich. I tried lowering the Mode 3 injector flow, but that didn’t get
me anything. I ended up setting that back to normal. Also, the tach
still doesn’t work, and neither does my optical tach, or a program on the
Ipaq called RPM from Sound. Maybe I’m just imagining that it’s
running.
After the first run, I took the EC-2 connector apart, and
started ohming every connection to make sure it was right. I found one
wire that I connected to the wrong place. Great connection, but wrong
place, so no points. It was the “mixture control voltage” wire that
goes from the EC-2 pin 26, to the PCM pin 15. I put it on pin 12 of the
PCM originally. Anyway, I got that fixed, tightened the POS Earls
fittings, and tried putting a small cap between the tach signal (Rotor 2
leading ignition trigger) and the tach. As you can tell, I’m
getting desperate.
Run two proved that the mixture knob does do something after
all. Hooking up the wire helped that part of it. There’s no
change in the primary secondary switch behavior though. From looking at Tracy’s
instructions, it appears that he compensates for the loss of a pair of
injectors by turning on the cold start function, which doubles the fuel.
Since the primaries are the only ones working at low power, when you turn them
off, the engine SHOULD quit, no matter how much to try to double the
fuel. Must confirm this, but it seems like it’s normal, though it
sure didn’t work that way Friday. Of course all bets are off when
you have bad connections and a miss-run wire. I checked the timing at
about 2500 rpm, and found it to be around 0 degrees, or TDC. I adjusted
the CAS for about 19 degrees, figuring that it will advance 4 degrees at high
power. The engine is running very well at 2500 rpm and above. I
mean spooky smooth. I’m afraid to run it too high at home, for fear
of it getting away from me, so I’ll wait until I get to the airport, have
the wings attached, and can be at the controls. Even at 3000 rpm (the
optical tach was working some now) it seems VERY strong. I just can’t
believe the power it seems to have.
The engine lopes at lower rpm, below about 2000 rpm, and won’t
run below about 1500 or so. I haven’t tried to do anything with the
air bleeds on the throttle body, so maybe that will help. I’m
pretty sure it’s just a tuning issue though.
The best news of all- no more leaks! If I confirm that
the engine is supposed to quit at low power when you turn off the primary
injectors, I’ll be clear for departure to the airport.