Greetings,

The following is my log from today.  Suffice it to say that I'm pretty disgusted.  Based on the number on my secondary injectors, it does appear that they should be 50 lb/hr (525 cc/min) injectors.  That should be pretty close to the stock 550's I would think, but they sure don't act like it.  FWIW, they are MSD-2013 injectors, which are actually made by Rochester as a #17104487. 

Rusty (Maybe beer will help <g>)

8-17-03  /  8 hours  /  1336 total

Started the engine with new injectors, and didn’t note any improvement (grumble, grumble).  Here’s the troubleshooting sequence.  All testing today was at low power of 3000 rpm and below, and the backup controller never made any difference.

Original condition: 

Normal – rough  (using primaries)

Primary sw off- smooth (using secondaries)

Secondary sw off- rough (using primaries)

Swapped Primary and Secondary wires in the engine compartment:

Normal- rough (using secondaries)

Primary sw off- rough (using primaries)

Secondary sw off- smooth (using secondaries)

The above test is of course a contradiction, but I tend to believe the individual tests, not the one with both switches on.

Replaced Primary injector connectors (pri and sec wires still reversed):

Things do seem better, but it’s hard to believe, especially since the original plugs looked so much better than the ones that I have installed now.  Still not sure this made a difference.  The engine will now run reasonably well with either primary or secondary switch off, but I noticed that the mixture is way different for each.  Maybe this has been part of the problem all along.

Put the primary and secondary wiring back to normal, but left the replacement primary plugs installed:

I can still make either set of injectors run the engine alone, but turning on the secondaries, when at 12” MAP makes the mixture go crazy, and I can’t seem to find a mixture setting that is smooth.  I can’t see why turning the secondary injectors off and on makes any difference at this power setting, since they aren’t supposed to be on anyway.  Tried manually setting mode 7 at 15” again, and nothing changed (as it shouldn’t).

Did some testing with primary and secondary injectors.  Cleared the settings in the EC-2 to the default MAP.  Ran with primaries only, and the mixture was way rich.  Turned the mixture knob all the way down, and still too rich.  Used mode 1 to lower the mixture until it was about right with the mixture knob at the 9:00 position.  Switched to the secondaries only, and the mixture is way lean.  Had to turn the mixture knob to the 3:00 position to get the right mixture.  With either primary or secondary injectors adjusted for decent mixture, they will idle down to about 1000 rpm fairly smoothly, so there’s no injector problems it would seem.  Once I figured out the sequence, I could quickly turn the mixture where it would need to go, and switch the switches.  Using this method, I could transition between primaries and secondaries.  It sure doesn’t seem like there should be 180 degrees of mixture knob difference between sets of injectors.  I’ll be double-checking the MSD injectors that I got for the secondaries.  They were supposed to be 550’s I thought, so they should match my primaries.  The MSD number on the injectors is “8132 17104487”.

I tried without success to make the engine run right with both sets of injectors enabled.  Just not sure what the problem is.  I couldn’t seem to do much good, other than correcting as needed with the mixture knob. 

Part of the problem now is that the air fuel gauge doesn’t seem to be registering correctly.  I noticed this the other day also.  Now that the sensor is pretty toasty, the meter reads two bars over the middle of the gauge.  Turning the mixture up, or down makes a noticeable change in the engine, but not on the gauge.  This is partly what led me to change the injectors, and now I doubt there was anything wrong with them.    

To make matter even more confusing, at some point, I noticed that turning off and on the secondaries at very low power stopped making a difference in the mixture.  This is how you would expect it to work, but it sure isn’t how it was working a few minutes earlier!!! 

I’m just about ready to send the computer back to Tracy for a checkout.  Very disgusted.  Not sure what else to try.