8-18-03  /  5 hours  /  1341 total

Started by taking the top skin off, and swapping the vacuum lines to the controllers.  I now have a line from rotor 1 to the A controller, the fuel regulator, and the boost gauge.  There is another line from rotor 2 to the B controller. 

I checked the boost gauge against my mityvac, and it seemed to be at least in the ballpark.  There was as much as 2-3 in difference in vacuum at around 20 in, but I didn’t really make note of which one was higher.  Since the mityvac has a cheaper gauge than the boost gauge, I wouldn’t know which to believe anyway.  I wish I had made some notes, and also checked my other automotive test gauge.

While I had the top cover off, I checked the cold start wiring for the zillionth time, and also clipped a test lead to it so I could monitor the voltage.  Everything was hooked up correctly, and it did exactly what it was supposed to do during the runs.  Turning on and off the secondary switch while at low power didn’t make any difference, so all that is fine. 

Re-installed the better primary connectors, and found no problems with them during the runs. 

The test Tracy wanted me to perform was to swap the primary and secondary wires again, and make note of which set of injectors is rich or lean.  So, I did this, and got the following results:

Normal- smooth, turning off and on secondary makes no diff at low power.

Primary sw off- (using primaries) smooth with mixture turned down to about 8:00 position.

Secondary sw off- (using secondaries) smooth, with mixture turned up to 2:00 position.

This confirms that the MSD injectors, that are installed in the secondary position are flowing far less fuel than they should be.  Not sure what I’ll do about this now. 

Also, during this run, I had my automotive test gauge hooked up to the B controller, while watching the boost gauge on the A controller.  There was always about a 3 in vacuum difference between the two, and I chalked it up to crappy gauges. 

Tracy mentioned that the preference was to have the smaller injectors as the primaries, so I left the wires swapped, so the MDS injectors would operate as the secondaries.   I proceeded to try to tune the engine with this setup.  With the exception of the transition point, the engine is now running pretty darned well on the A controller.  I then tried to tune the B controller, and found that I couldn’t make it idle, or run at low power, though it’s fine at higher power.  It acts as if it’s in the transition at idle and just above, and I believe that’s the case.  I’m starting to think there really IS a 2-3 in difference in vacuum between the two ports on the TB.  Since I swapped those ports at the beginning of the day, I’m now seeing on the B controller, the unruly behavior that was happening before on the A controller, and A is behaving better.  I’ll T these two ports together next, as Tracy suggested earlier.   

Finally, the Tiny Tach is NOT working properly again.  It’s fine at low rpm, but wanders around at high rpm.  I couldn’t get any stable reading at full power.  Gotta find another tach, preferably one that works with a 5V pulse.

So, to recap.  There is defiantly a huge difference in the flow rate of the primary Mazda 550 injectors, and the MSD-2013 525 injectors.  There’s NO way these are flowing 525 cc/min.   This is causing a big problem at transition.  At that throttle setting, it’s very rough, and I can’t do anything to help with the mixture.  Turning it up is worse, and turning it down is worse.  I don’t see how I can tune this out.  The only option is replacing the injectors, or trying to set the transition below idle, so all 4 injectors are on all the time.  Probably going to try this next.

The other problem is that my transition is falling right around idle and low throttle on the B controller.  T-ing the ports together should at least make both controllers behave the same.