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.